Recent literature - or what is somewhat older but only recently came to my attention - includes the following papers on Neotropical alnd snails. Abstracts are those from the authors.

Arruda, J., Pereira, D., Bergonci, P., Pinheiro dos Santos, C., Mansur, M., 2009. New records of Omalonyx matheroni (Pontiez & Michaud, 1835) (Mollusca, Gastropoda, Succineidae) for the Sao Paulo and Parana States. Novos registros de Omalonyx matheroni (Pontiez & Michaud, 1835) (Mollusca, Gastropoda, Succineidae) para os Estados de Sao Paulo e Parana, Brasil. - Biotemas 22:187-190. Link.
Omalonyx matheroni is a succineid gastropod that lives on aquatic macrophytes and on emergent vegetation in the wetlands of inner deltas, lakes and dikes. Occurrences of this species were recorded in the municipalities of Ibitinga (SP) and Paranagua (PR), broadening its distribution southwards in South America. Until now this species had been recorded in Demerara (Guiana), Zanderij and Belwaarde (Suriname), Guiana Francesa, Peru, Limoncocha (Equador), Amazonas, Para, Pernambuco, Rio de Janeiro and Minas Gerais (Brazil), as well as on the islands of Guadalupe and Trinidade.

de Medeiros Carvalho, C., Pinheiro da Silva, J., Mendonca, C., de Almeida Bessa, E., D'Avila, S., 2009. Life history strategy of Leptinaria unilamellata (d'Orbigny, 1835) (Mollusca, Pulmonata, Subulinidae). - Invertebrate Reproduction and Development 53: 211-222.
Life history theory predicts that the patterns of resource allocation in animals are associated with different strategics, selected in the course of evolution. In the present study, the life history of Leptinaria unilamellata was characterized under laboratory conditions. We determined the growth, reproduction, and longevity patterns of this species and elucidated the strategy related to the development of embryos, through direct observations and examination of the morphology of the gravid uterus. Furthermore, we attempted to analyze the glycogen and galactogen contents of the albumen gland, digestive gland and cephalopedal mass in order to understand energy allocation to life history traits, for three life stages. Leptinaria unilamellata 's life history is characterized by great longevity, a short juvenile phase, early sexual maturity, and repeated reproductive events, with little reproductive effort at each event and some mortality shortly after the first reproduction. In the terraria, we found juveniles but no eggs. However, the results of the anatomical study showed no morphological connection between the embryos and the parental organism. Thus, this species should be described as ovoviviparous rather than viviparous. Egg retention in the parent organism is the primary cause ofthe release of juveniles, instead of eggs, enabling the offspring to withstand environmental stress. The higher quantity of galactogen found in the adults' albumen gland, as compared to juveniles and senescent individuals, as well as the ratio of glycogen to galactogen, reveal the allocation of energy to reproduction rather than to growth. The remaining energy is directed to the maintenance of homeostasis. Such pattern was confirmed by the low levels of glycogen and galactogen observed in the senescent stage, compared to the juvenile and adult stages. In the life strategy of L. unilamellata, the distribution ofthe reproductive effort among many events associated with ovoviviparity indicates a long-term investment in reproductive success.

dos Santos, S., Viana, T., Fonseca, F., 2008. First record of the micro-predator Huttonella bicolor (Hutton, 1834) (Gastropoda, Streptaxidae) on Rio de Janeiro City, Brazil. - Biociencias 16:145-148. Link.

Tags: literature

Back in Leiden, one of the first things I did is to check the new journal arrivals in the library. As long as journals appear on paper, it is a great joy to physically browse through them and to find interesting publications.



One of them is a paper on a new species of Spixia, S. cuezzae, by Eugenia Salas Oroño. It was found in Argentina, Prov. Córdoba, Punilla Dept., road from Capilla del Monte to San Marcos Sierras, 944 m. Holotype IML 15284.



The new species is described in the context of a revision of the genus, for which Eugenia has been doing much work during the past years. One characteristic of this group is the fine micro-sculpture on the whorls.
She will defend her Ph.D. thesis soon I guess.

Reference:
Salas Oroño, E., 2010. A new species of Spixia from Argentina (Gastropoda, Stylommatophora, Odontostominae). - Journal of Conchology 40: 305-313.

Tags: Argentina, Spixia, literature

Recently, a special number appeared of Biology and Philosophy on different views on the Tree of Life (ToL).

A paper by O’Malley at al. introduces the debate.
The ‘Tree of Life’ is intended to represent the pattern of evolutionary processes that result in bifurcating species lineages. Often justified in reference to Darwin’s discussions of trees, the Tree of Life has run up against numerous challenges especially in regard to prokaryote evolution. This special issue examines scientific, historical and philosophical aspects of debates about the Tree of Life, with the aim of turning these criticisms towards a reconstruction of prokaryote phylogeny and even some aspects of the standard evolutionary understanding of eukaryotes. These discussions have arisen out of a multidisciplinary collaboration of people with an interest in the Tree of Life, and we suggest that this sort of focused engagement enables a practical understanding of the relationships between biology, philosophy and history.
Ford Doolittle argues why we need a more realistic public understanding of evolution, stressing the fact that evolutionairy theory is only versatile explanotory toolkit.
The paper by Rieppel explores different, conceptual views and expresses the need to distinguish between different conceptual theorems.
The history of biological systematics documents a continuing tension between classifications in terms of nested hierarchies congruent with branching diagrams (the ‘Tree of Life’) versus reticulated relations. The recognition of conflicting character distribution led to the dissolution of the scala naturae into reticulated systems, which were then transformed into phylogenetic trees by the addition of a vertical axis. The cladistic revolution in systematics resulted in a representation of phylogeny as a strictly bifurcating pattern (cladogram). Due to the ubiquity of character conflict—at the genetic or morphological level, or at any level in between—some characters will necessarily have to be discarded (qua noise) in favor of others in support of a strictly bifurcating phylogenetic tree. Pattern analysts will seek maximal congruence in the distribution of characters (ultimately of any kind) relative to a branching tree-topology; process explainers will call such tree-topologies into question by reference to incompatible evolutionary processes. Pattern analysts will argue that process explanations must not be brought to bear on pattern reconstruction; process explainers will insist that the reconstructed pattern requires a process explanation to become scientifically relevant, i.e., relevant to evolutionary theory. The core question driving the current debate about the adequacy of the ‘Tree of Life’ metaphor seems to be whether the systematic dichotomization of the living world is an adequate representation of the complex evolutionary history of global biodiversity. In ‘Questioning the Tree of Life’, it seems beneficial to draw at least four conceptual distinctions: pattern reconstruction versus process explanation as different epistemological approaches to the study of phylogeny; open versus closed systems as expressions of different kinds of population (species) structures; phylogenetic trees versus cladograms as representations of evolutionary processes versus patterns of relationships; and genes versus species as expressions of different levels of causal integration and evolutionary transformation.
Mallet states that the species concept as currently understood, appears to be returning to more Darwinian views on species, and to a fuller appreciation of what Darwin meant. As O’Malley shows, the dichotomy of life concept held by several biologists from the 20th century, was formulated from a too narrow perspective.
Morgan discusses new concepts of biodiversity and species delimitation, and argues for a phenetic rather than a phylogenetic measure of distance and the use of morphospaces.
With a number of papers focussed on understanding microbial speciation, sometimes a paper on this topic seems to have relevance outside the eukaryotic realm. Belko discusses the balance between vertical descent and phylogenetic networks.
Velasco and Sober give a methodological contribution by discussing model selection and phylogentic inference.
A phylogeny that allows for lateral gene transfer (LGT) can be thought of as a strictly branching tree (all of whose branches are vertical) to which lateral branches have been added. Given that the goal of phylogenetics is to depict evolutionary history, we should look for the best supported phylogenetic network and not restrict ourselves to considering trees. However, the obvious extensions of popular tree-based methods such as maximum parsimony and maximum likelihood face a serious problem—if we judge networks by fit to data alone, networks that have lateral branches will always fit the data at least as well as any network that restricts itself to vertical branches. This is analogous to the well-studied problem of overfitting data in the curve-fitting problem. Analogous problems often have analogous solutions and we propose to treat network inference as a case of model selection and use the Akaike Information Criterion (AIC). Strictly tree-like networks are more parsimonious than those that postulate lateral as well as vertical branches. This leads to the conclusion that we should not always infer LGT events whenever it would improve our fit-to-data, but should do so only when the improved fit is larger than the penalty for adding extra lateral branches.
In Franklin-Hall’s view, the ToL may play an important role in the dynamic modeling of evolution. Finally, Bapteste and Burian make a plea for a more integrative approach.
Recently improved understanding of evolutionary processes suggests that tree-based phylogenetic analyses of evolutionary change cannot adequately explain the divergent evolutionary histories of a great many genes and gene complexes. In particular, genetic diversity in the genomes of prokaryotes, phages, and plasmids cannot be fit into classic tree-like models of evolution. These findings entail the need for fundamental reform of our understanding of molecular evolution and the need to devise alternative apparatus for integrated analysis of these genomes. We advocate the development of integrative phylogenomics for analyzing these genomes and their histories, with tools suited to analyzing the importance of lateral gene transfer (LGT) and of DNA evolution in extra-cellular mobile genetic elements (e.g., viruses, plasmids). These phenomena greatly increase the complexity of relationships among interacting genetic partners, as they exchange functional genetic units. We examine the ontology of functional genetic units, interacting genetic partners, and emergent genetic associations, argue that these three categories of entities are required for a successful integrated phylogenomics. We conclude with arguments to suggest that the proposed new perspective and associated tools are suitable, and perhaps required, as a replacement for the bifurcating trees that have dominated evolutionary thinking for the last 150 years.

These papers are open access and are recommended to those who like to sharpen their thoughts on evolutionary theory, species concepts and methodologies used to investigate them.

Tags: taxonomy, methodology, phylogeny, literature

Having analyzed so far only ITS/28S data, I’m now trying to combine different partitions from both nuclear and mitochondrial DNA. The first step is to concatenate ITS/28S and histone 3. So far, so good (but after getting around some stumble blocks). Some useful literature in this respect is Planet (2006). For recent reviews of general methodologies, see Blair & Murphy (2010) and Pausas & Verdú (2010).



References:
Blair, C. & Murphy, R.W., 2010. Recent trends in molecular phylogenetic analysis: where to next? - Journal of Heridity (in press; doi:10.1093/jhered/esq092).
Pausas, J.G. & Verdú, M., 2010. The jungle of methods for evaluating phenotypic and phylogenetic structure of communities. - BioScience 60: 614-625.
Planet, P.J., 2006. Tree disagreement: measuring and testing incongruence in phylogenies. - Journal of Biomedical Informatics 39: 86-102.

Tags: DNA, literature

Bioinformatics, or more precise, biodiversity informatics, is an emerging field in which much progress already has been made. However, overarching scientific questions seem to be absent and therefore major, guiding goals are missing.
In a recent review, Townsend Peterson et al. (2010) have tried to bridge this gap by posing a number of Big Questions.

According to these authors, “biodiversity science in general can and should evolve from a purely descriptive cataloguing endeavour into a predictive, scientific exploration of space, time and form”. This seems only logical.

This figure presents a framework of biodiversity informatics data realms, showing potential cross-links between some of them that are currently unlinked.



Given this framework the following areas of analysis could become available.
1. Geography and ecology of past life.
This topic is part of global change biology and seems to be very important when we try to anticipate biotic responses to future environmental change and biodiversity loss. The interaction of intrinsic and extrinsic factors on species’ responses remains little known.
2. Biota-wide picture of diversification and interaction
Community ecology currently focuses on closely relatives or known mutualists. However, a broader perspective is needed, leading to a more integrative view of both biotic interactions and biological diversification. Phylogenetic frameworks, geographic distributions and species niche estimates are key elements. This could result in insights incorporating ecological dimensions and likely shifts in distribution during historic times.
3. Future (novel) communities
Palaeontological evidence shows that in the past communities existed differing from extant counterparts. The shifts in novel species assemblages due to changing climates and the introduction of alien species may need further developments in niche modelling, leading to environmental change scenarios and future distribution predictions.
4. Integrating phenotype and genotype
Linking rich biodiversity data sets on phenotypes and genotypes of individuals, populations and species could be integrated over space and visualized in various dimensions. This would provide a view on how phenotype and genotype interact with geography and ecology.
5. Synthetic conservation planning
Only recently, conservation planning involves prioritizing using multi-factor, multi-temporal scenarios, which have the potential of covering more of the true complexity. This could lead to a more synthetic and robust view of conservation and nature resources management.

Some the key next steps involve data integration across disparate databases, data quality assurance, detecting errors and avoiding pseudoreplication, and finally, dealing effectively with scale.

All this - and more details in the paper - provides a challenging outlook. Undoubtedly, biodiversity informatics will become Big in the (near) future. But for me the key question is: what is the taxon involved? Having seen various incidents where people loose sight of the organism at stake, and focus instead on methodological questions and techniques to be used. “It’s the taxon, stupid”; even if this involves a purely descriptive cataloguing endeavour...

Reference:
Townsend Peterson, A., Knapp, S., Guralnick, R., Soberon, J. & Holder, M.T., 2010. The big questions for biodiversity informatics. - Systematics and Biodiversity 8: 159-168.

Tags: bioinformatics , methodology, publishing, literature

Even at high altitudes you may be able to find interesting snail habitats. In the Andes they range from the puno in Bolivia and Peru to the páramo in Ecuador and Colombia.




I like those high altitude habitats, as they offer both plenty of natural conditions (relatively unspoiled by human kind) and interesting ecological niches for snails. In Colombia there are niches in (sub)páramo areas for e.g. Stenostylus and Plekocheilus.


Although there is now a huge amount of scientific literature on páramos - thanks to the work of Thomas van der Hammen, Antoine Cleef, Henry Hooghiemstra and many Colombian co-workers - the more easy-accessible literature is sparse. Last week my attention was drawn to a very good summarizing publication on Colombian páramos. It has also very good maps of the different páramo areas, like e.g. here the map of the Tatamá Natural Park at the border of Chocó, Valle del Cauca and Riseralda.



Thanks Francisco for sharing this useful source of information.

Tags: Colombia, ecology, literature

In the continuous stream of taxonomic revisions and descriptions of new species, e.g. in Zootaxa, it is noteworthy that this journal has introduced a ‘Correspondence’ section besides the more lengthy ‘Article’. In a recent number, there was such a correspondence about the rediscovery of a tiny charopid, Zilchogyra franzi Weyrauch, 1965, from the Sierra de la Ventana in eastern Argentina (Delhey et al., 2010).

Zilchogyra franzi was described from a single specimen, collected amoung ferns in “a humid hollow lined with dark soil” in the Sierra de la Ventana. Three biologists from the University in Bahia Blanca tried to hunt this species for several years. And although they were successful in obtaining both living specimens and a number of shells, it is clear from their limited findings that this is a relatively rare species which occurs in low numbers.



The authors provide a redescription and give additional features based on SEM research.
As micromolluscs usually get much less attention, this paper is a welcome contribution to our knowledge on Neotropical land snails.

Reference:
Delhey, V.K., Pizá, J. & Burela, S., 2010. Zilchogyra franzi Weyrauch, 1965 (Gastropoda: Charopidae), a minute landshells rediscovered in Sierra de la Ventana (Southern Pampas, Argentina). - Zootaxa 2450: 61-64.

Tags: Charopidae, Argentina, literature

A website where (very irregularly) two journals appear that might be interesting for those interested in Neotropical biology, is the website of the Caribbean Natural History Group.

The first journal is Cocuyo. This journal started in 1994 and is presented as a Newsletter of the Invertebrate Zoologists of the Antilles. The content is mainly centered on Cuba. Several malacological papers have appear in the 17 issues to date. All issues can be downloaded as PDFs.

The other journal is Solenodon, Antillean journal of zoological taxonomy. In the eight issues that appeared since the start in 2001, no malacological papers have been published.

Tags: West Indies, literature

As a sequel to his previous paper on fossil Cerion from the Bahamas, Paul Hearty (2010) has published a new paper on this topic.

His abstract is as follows:
Despite the nearly 600 named species of the land snail Cerion, studies of the geological and paleonto- logical framework of modern species are few. To address this deficiency, the biostratigraphic succession of Cerion was investigated at several areas on Long Island, Bahamas. A chronostratigraphic framework was developed through whole-rock and Cerion land snail aminostratigraphies. About 175 individual Cerion shells from last interglacial and Holocene deposits were age-ranked using stratigraphic position and amino acid racemization (AAR) geochronology. AAR ages were generated using an existing AAR-14C age model for Cerion from the central Bahamas. The age structure of Cerion fossils in sediments was determined with AAR ages, and the magnitude of ‘‘dead carbon’’ anomalies was evaluated using this chronological approach.
Temporal changes in gross shell morphology were examined from four study areas. The last inter-glacial, marine isotope stage/substage (MIS) 5e (Aminozone E) is characterized by generally large shells and in some cases, bimodal sets of very small (a shells) and very large forms (b shells) coexisting in the same stratigraphic levels (primarily soils), which may encompass the transition from between MIS 5e and 5d/c. Similar bimodality of nearly identical a and b shell forms and sizes is observed at other late MIS 5e sites from the furthest reaches of Great Bahama Bank (including Long, Exumas, Eleuthera, and New Providence Islands). The widespread distribution of a and b forms in soils capping MIS 5e marine and eolian deposits implies that there may have been a synchronous, regional morphological convergence on Great Bahama Bank. None of these forms are observed in Holocene deposits of Aminozone A.



The earliest MIS 1 Cerion appear in a oolite deposited 6500 a BP, and are of intermediate size compared to the Pleistocene a and b forms. As MIS 1 progressed, the diversity of shell sizes and shapes increased into modern times. The greater variety of shell forms over the past 1000–2000 a suggests that humans may have played a role in the introduction and redistribution of Cerion across the region. The potential for frequent and widespread human introductions, combined with the propensity of Cerion to hybridise freely may explain the farrago of shell sizes and shapes in the recent snail faunas of Long Island and other Bahama islands.

Reference:
Hearty, P.J., 2010. Chronostratigraphy and morphological changes in Cerion land snail shells over the past 130 ka on Long Island, Bahamas. - Quarternary Geochronology 5: 50-64.

Tags: Bahamas, Cerion, literature

A new list on the non-marine molluscs found in Santa Catarina State in southern Brazil has been published (Agudo, 2010). The list totals 160 taxa (species and subspecies) and is available here.

Reference:
Agudo-Padrón, A.I., 2008 [2010]. Listagem sistemática dos moluscos continentais ocorrentes no Estado de Santa Catarina, Brasil. - Comunicaciones de la Sociedad Malacológica del Uruguay 9: 147-179.

Tags: Brazil, literature

In the most recent number of the American Malacological Bulletin a series of papers was published as a result of the AMS 2008 Leslie Hubricht symnposium on land snails. One of these papers is by Naranjo-García & Fehy (2010).

In this paper they discuss the distribution of the lesser represented land snail families in Mexico, based on literature and unpublished data. This concerns only families represented with less than 30 species in the country; in total 34 families.



For a number of families they give distribution maps of species or compiled data at generic level. The current status is discussed of each family. In the discussion distribution patterns are discussed. In the conclusions several states within Mexico are mentioned which are under-sampled.

Despite a vast base of records, lots of work remains to be done by those Neotropical snail lovers residing or visiting Mexico.

Reference:
Naranjo-García, E. & Fehy, N.E., 2010. The lesser families of Mexican terrestrial mollusks. - American Malacological Bulletin 28: 59-80.

Tags: Mexico, literature

Three new books have been published or announced, that might be interesting for those interested in the Cuban malacofauna and the geology and biogeography of Amazonia.




The first is a book by Espinosa & Ortea, published by Spartacus Foundation and the Cuban Zoological Society. I haven’t seen it myself yet, but I found the following announcement of a book dealer:
This is a gorgeous book and I think that the photography here is possibly the best live animal photography that I have seen in all of my other titles. It is simply amazing and the book is also an amazing work. Its focus is to introduce us to the numerous families of terrestrial mollusks that live in Cuba.  Most of the shells are show alive in their natural habitat in extreme close up. The text (in Spanish) gives us an overview of the shell family, its habitat , the characteristic of these shells and a lot of background information. My Spanish is not good enough to understand the more technical details that the authors have written but from what I can understand it is a carefully written and thoroughly researched book. The authors and the photographer are prominent workers in the scientific field and it is a shame that their names and their works are not well know in the USA. The last section of their book is a check list of 1393 species of land-shells found in Cuba.

From what I saw of the pictures in the announcement, some will be the same as those used in the book of González. They partly share the same photographer. Hopefully, they have corrected all the errors they made in the previous version of their checklist (Espinosa & Ortega, 1999). But a judgement should be postponed till I have actually seen the book.



The second book on Cuban terrestrial snails is, if possible, even more obscure and curious. It is a publication based on an unfinished manuscript of Torre & Bartsch. There is a quite complication story to this book (which is beyond the scope of this blog), that has been published as a tribute to Carlos de la Torre y Huerta (1858-1950) in 2008. From what I know, several new species are described in this book, casting an interesting question on the rules of nomenclature. Are they to be credited to the original authors (as posthume work) or to the editor of this book?
Again, let’s first see this book before making a judgement.

Finally, an impressive book will be published on February 16, entitled “Amazonia: landscape and species evolution. A look into the past”. I had the privilege to have a sneak preview and I can assure you this will be a reference work for those working on the biogeography of northern South America.



This book focuses on geological history as the critical factor in determining the present biodiversity and landscapes of Amazonia. We explore the different driving mechanisms for landscape evolution by reviewing the history of the Amazon Craton, the associated sedimentary basins, and the role of mountain uplift and climate change. Throughout the book we provide an insight into the Meso- and Cenozoic record of Amazonia that was characterized by fluvial and long-lived lake systems and a highly diverse flora and fauna. This fauna includes giants such as the ca. 12 m long caiman Purussaurus, but also a varied fish fauna and fragile molluscs, whilst fossil pollen and spores form relics of ancestral swamps and rainforests.

Finally, we review the molecular datasets of the modern Amazonian rainforest and aquatic ecosystem, and discuss the possible relations between the origin of Amazonian species diversity and the palaeogeographic, palaeoclimatic and palaeoenvironmental evolution of northern South America. The multidisciplinary approach in evaluating the history of Amazonia has resulted in a comprehensive volume that provides novel insights into the evolution of this region and can serve as reference for a variety of scientists working in Amazonia.

The book is written by leading scientists of the Amazonian research community and should be of interest to all students and researchers concerned with the natural history of Amazonia. Potential readers will include geologists, geographers and biologists who wish to understand the evolution of landscapes and biota of this unique region.

I hope to briefly review this book after its publication.

References:
Espinosa, J. & Ortega, J., 2009. Moluscos terrestres de Cuba: 1-191. Spartacus Foundation/Sociedad Cubana de Zoología.
Hoorn C. & Wesselingh, F. (eds.), 2010. Amazonia: landscape and species evolution. A look into the past: 1-447. Wiley-Blackwell.
Torre, C. de la & Bartsch, P., 2008. Los moluscos terrestres Cubanos de la familia Urocoptidae: 1-730 + 1-23. Editoria Científico-Técnica, La Habana/Ruth Casa, Panama.

Tags: literature, varia, Cuba, geology, Brazil, Peru, Ecuador, Colombia, Venezuela

The yearly newsletter Tentacle has been published, now for the first time on internet only. Another e-journal to mark the transition to the paperless world.



The new issue 18 has several articles that are interesting to Neotropical snail lovers.
Ignacio Agudo has an interesting wrap-up of 13 years inventory work in Brazil, Santa Catarina state. He has an impressive list of freshwater and terrestrial molluscs needing conservation attention. In total, 37 taxa out of the 116 recorded for this state are considered either vulnerable, endangered or critically endangered according to IUCN Red List criteria. Amoung the latter category are Drymaeus papyrifactus, Anthinus turnix, and Bahiensis punctatissimus.

Agudo & Lenhard give a concise overview of the introduced molluscs in Brazil. Their list has 28 terrestrial gastropods, 12 freshwater and 5 marine taxa. They also discuss seven species of which the introduction is unresolved (some authors consider them native) and 16 taxa that have potential to invade Brazil.

Conservation issues in eastern Cuba are the subject of two other papers.
Maceira & Batista discuss the problems in El Gigante Ecological Reserve. An inventory of this 10.5 km2 large reserve lists 10 species (80% endemism) of land snails. Human activities resulting in destruction and fragmentation of the habitats and introduction of wide-spread species, like Deroceras reticulatum and Succinea angustior, threatens the malacofauna.
In a second paper Maceira, Pascual & Reyes report on the species found in a second reserve, Silla de Romano. In this 2141 ha area, 25 species (76% endemic) were found during an inventory in October 2008. Here too, destruction of habitats and fragmention threatens the snail population. Wild pigs are predating on some species as food.

Clavijo et al. describe the conservation priorities for Uruguayan land and freshwater molluscs. However, land snails are only briefly mentioned in a Table and the emphasis in this paper is totally on freshwater snails. According to these authors, 46 species of terrestrial Gastropoda (63% of total) are in need of conservation action.

Finally, Régnier shows that records of extinct molluscs in the Red List are biased. A critical revision of the list revealed that the 279 species already listed, 288 species must be added. Of this new total of 566 taxa, 422 are terrestrial.

References:
Agudo-Padrón, A.I., 2010. The mollusc fauna of Santa Catarina State, southern Brasil: knowledge gained from 13 years of research. - Tentacle 18: 32-37.
Agudo-Padrón, A.I. & Lenhard, P., 2010. Introduced and invasive molluscs in Brasil: a brief overview. - Tentacle 18: 37-41.
Clavijo, C., Carranza, A., Scarabino, F. & Soutullo, A., 2010. Conservation priorities for Uruguayan land and freshwater molluscs. - Tentacle 18: 14-16.
Maceira Filgueira, D. & Batista, Y., 2010. Land molluscs conservation problems in El Gigante Ecological Reserve, eastern Cuba. - Tentacle 18: 20-22.
Maceira Filgueira, D., Pascual Pérez, R. & Reyes Brea, J., 2010. Land molluscs of the Silla de Romano Protected Area, north coast of Cuba, and their conservation problems. - Tentacle 18: 22-25.
Régnier, C., 2010. Many unnoticed extinctions: do molluscs really account for half the toll? - Tentacle 18: 2-3.

Tags: conservation, Brazil, Cuba, Uruguay, literature

Lissachatina fulica is a well-known pest now in South America (Borrero et al., 2009). Studies on its biology, however, are relatively scarce and especially the influence of climatic variables and human density on growth and condition of this species.

Albuquerque et al. (2009) studied populations in Brazil, Bahia, Lauro de Freitas. They collected samples of the snails and took measurements of shell height and total weight as proxy for condition. Five environmental variables were considered: temperature range, mean temperature, humidity, precipitation and human population density.

The results show that humidity had a significant influence on length and weight, and temperature was the only significant factor that influenced condition. Partial regression showed that the influence of human population density partially overlapped the climatic factors.

References:
Albuquerque, F.S., Peso-Aguiar, M.C., Assuncao-Albuquerque, M.J.T. & Galvez, L., 2009. Do climate variables and human density affect Achatina fulica (Bowditch) (Gastropoda: Pulmonata) shell length, total weight and condition factor? - Brazilian Journal of Biology 69: 879-885.
Borrero, F.J., Breure, A.S.H., Christensen, C., Correoso, M. & Mogollón Avila, V., 2009. Into the Andes: three new introductions of Lissachatina fulica (Gastropoda, Achatinidae) and its potential distribution in South America. - Tentacle 17: 6-8.

Tags: Brazil, Achatina, literature

Alien slugs can develop easily in pest species and the increase of global horticultural trade is facilitate the entrance of new invaders (Cowie et al, 2008). This seems to apply also for Milax gagates (Draparnaud, 1801). The occurrence of this species has now been confirmed for the southern state Santa Catarina in Brazil (Agudo-Padrón, 2009).



Reference:
Agudo-Padrón, I., 2009. First confirmed record of the exotic slug Milax gagates (Draparnaud, 1801) in the Southernmost Brazil region. - Ellipsaria 11(3): 15-16.
Cowie, R.H., Hayes, K.A., Tran, C.T. & Meyer, W.M. III, 2008. Horticultural industry as a vector of alien snails and slugs: widespread invasions in Hawaii. - International Journal of Pest Management 54: 267-276.

Tags: Brazil, Milacidae, literature

Books dealing exclusively with Neotropical snails are rare. And even though the book ‘Coquillages et escargots de Guyane’ (Massemin et al., 2009) predominantly deals with seashells, it has a good section on land snails.

The subtitle reads ‘Seashells and snails from French Guiana’, indicating that it is bilingual. Basically, this is a French book with the larger part of the text translated into English (including identification keys). However, the first part of the book is in French only; it deals with an introduction to molluscs, geography of French Guiana and habitats of snails.


Simpulopsis corrugatus Guppy, 1866

The second part is an illustrated guide to all the species known from this country and adjacent areas. Of the nearly 400 pages, 60 are devoted to land snails. An illustrated key is given to families and species, followed by a characterization of each family and treatment of each species. Ecological data are provided, as well as distribution maps of the occurrence within French Guiana. Each species is beautifully photographed. Of many species, also pictures of living specimens are given.
An index to scientific names, a glossary and a short bibliography make this book a complete reference guide.

Going through the book, I noticed only one apparent mistake, Nesopupa maasseni being misspelled most of the times the species was cited. But such an error is easily forgiven in the context of this beautiful publication.
Already three years ago, during WCM, there were rumours about this book. The authors and editors surely have taken their time. But it was really well worth waiting for. I would like to congratulate Olivier Gargominy, author of the chapter on terrestrial snails, for delivering such a nice piece of work.

Reference:
Massemin, D., Lamy, D., Pointier, J.-P. & Gargominy, O., 2009. Coquillages et escargots de Guyane. Seashells and snails from French Guiana: 1-456. Mèze, Biotope / Paris, Muséum national d’Histoire naturelle.
Price € 70,00.

Tags: French Guiana, publication, literature

Alien snails can also come in handy. Helix aspersa is an introduced species in the Neotropics. Ianistcki et al. (2009) have used this species to monitor the air quality in a Brazilian city.


The purpose of this study was to biomonitor metropolitan areas of Porto Alegre (Brazil) for PAHs associated with atmospheric particles and check their effects on the DNA of the land mollusk Helix aspersa. The sampling sites are located in an urban area with heavy traffic: (i) Canoas, (ii) Sapucaia do Sul, and (iii) FIERGS/Porto Alegre. The samples were collected during a continuous period of 24 hours during 15 days using Stacked Filter Units (SFU) on polycarbonate filters (two separated size fractions: PM10-2.5 and PM<2.5). The concentrations of 16 major PAHs were determined according to EPA. Comet assay on H. aspersa hemolymph cells was chosen for genotoxicity evaluation. This evaluation shows that, in general, the smaller PM-size fractions (PM<2.5) have the highest genotoxicity and contain higher concentrations of extractable organic matter. In addition, associations between chemical characteristics and PM carcinogenicity tend to be stronger for the smaller PM-size fractions. DNA damage in H. aspersa exposed to atmospheric particulate in Metropolitan Area of Porto Alegre demonstrated association with PAHs in the fine filter (PM<2.5).

Reference:
Ianistcki, M., Dallarosa, J., Sauer, C., Teixeira, C.E. & da Silva, J., 2009. Genotoxic effect of polycyclic aromatic hydrocarbons in the metropolitan area of Porto Alegre, Brazil, evaluated by Helix aspersa (Müller, 1774). - Environmental Pollution 157: 2037-2042.

Tags: literature, varia

In another recent publication, Christine Parent and Guy Coppois tell the story of their fascination with Galápagos land snails and their concerns about conservation issues with these animals.


Coppois has a long experience with field work on these islands, visiting the archipelago for the first time in 1973 and continuing during 30 years. He succeeded to collect more than 80 taxa of bulimulids. One of his most remarkable finds was the discovery of living specimens of Naesiotus achatinellus (Forbes, 1850). This only one of the species with a very restricted distribution range and which probably has vanished into extinction. Several species are on the Red List of endangered species.
Habitat destruction and the negative impact of introduced predators and competition of alien pest species, like veronicellid slugs, may be considered the main causes of the decline of land snails on these islands.

The personal stories of both authors reveal their fascination with this group, which is a thankful subject for studies in evolutionary biology.


Reference:
Parent, C.E. & Coppois, G., 2009. On the snails’ trail: evolution and speciation among a vanishing tribe. In: De Roy, T. (ed.), Galápagos: preserving Darwin’s legacy: 74-81. Firefly Books, Richmond Hill, Ontario.

Tags: Ecuador, Naesiotus, conservation, literature

The land snails of the Galápagos archipelago are amoung the best studied Neotropical snails. Thanks to Christine Parent and co-workers, much progress has been made on our understanding of the ecology and phylogenetic relationships of this group (Parent & Crespi, 2006; Parent et al., 2008).

Recently, a new paper was published with details on the ecology of these species (Parent & Crespi, 2009). Although Galápagos bulimulids are not host-plant specific, they are distributed in space according to different local microhabitats, with differences in substrates, plant species, vegetation types and resting places. The authors also notice an elevational variation in shell shape associated with moisture levels, with more slender shells at lower elevations and more conical shells at higher.
In this study a three-level zonation is followed (coastal, dry lowland, humid highland). Endemic plant species are used as a proxy for resource and habitat complexity. The effect of ecological opportunity and intraspecific phenotypic variation is also quantified by the number of congeners. The results show that the number of congeners inhabiting the same vegetation zone is negatively correlated with the degree of intraspecific variation in shell shape and resource heterogeneity was positively correlated. Ecological opportunity is greatest on younger islands, where relatively high resource heterogeneity combines with low interspecific competition.

The main conclusion of this study is that competition and resource heterogeneity are significant determinants of interspecific phenotypic variation in the context of adaptive radiation.

It should be noted (again) that the taxonomic treatment of this group in this paper is misleading. Galápagos bulimulids are not Bulimulus but should be placed - for now - in Naesiotus. Their proper relationships and taxonomic placement will be treated in one of my upcoming papers. Nevertheless, the authors have done an insightful study into the ecological relationships, which stimulates further research.


Reference:
Parent, C.E. Caccone, A. & Petren, K., 2008. Colonization and diversification of Galápagos terrestrial fauna: a phylogenetic and biographical synthesis. - Phliosopical Transactions of the Royal Society, B 363: 3347-3361.
Parent, C.E. & Crespi, B.J., 2006. Sequrntial colonization and diversification of Galápagos endemic land snail genus Bulimulus (Gastropoda, Stylommatophora). - Evolution 60: 2311-2328.
Parent, C.E. & Crespi, B.J., 2009. Ecological opportunity in adaptive radiation of Galápagos endemic land snails. - American Naturalist 174: 898-905.

Tags: Ecuador, Naesiotus, ecology, literature

The Biodiversity Heritage Library is constantly improving. Not only the amount of works increases (now 838 titles tagged with “Mollusks”) and important recent works have been added (e.g., Bouchet & Rocroi’s publication), also their services have substantially improved.
A few weeks ago I discovered that they offered the service of downloading selected pages from a work as PDF. Until then, the only way was to consult the work either online or download it as a whole. Especially when you have low bandwidth, this can be a very time-consuming action, as most titles comprise many Megabytes. Therefore this service seemed very useful. When I first tested it, however, no results could be obtained. It appeared that the service was still under development and somehow I had entered their beta-website.

When I retried yesterday, the service worked flawlessly despite being announced as BETA.


When you know the pages on which the paper of your choice appeared, you can directly go to the dropdown menu and ‘Select pages to download’. An overview of the content appears, in which you can tick the pages you want.
Click on next and you will be prompted to enter the email address(es) where you want the PDF delivered.


Then you may lean back and wait. First a confirmation will arrive in your mailbox. After a short while (yesterday on average 10-15 minutes later) a message with the link to the PDF will follow.


Great service!

Tags: literature

Sometimes I’m wondering about the great variation in shell shapes and colour patterns observed within my group. They range from turrited to discoidal and everything in between. Many are unicoloured, but some are outrageous in their patterns.



Recently, a group of biophysics and mathematicians has published a paper about shell structure and patterns. Although it is focussed on aquatic snails, I think it is equally relevant for those interested in land molluscs.



Can you see which of the two is the real shell and which the simulated one?

With only a few parameters defining the morphospace, the authors were able to simulate a wide variety of shell shapes and colour patterns.

In this work, we have shown that a single neurosecretory model can replicate both the growth of mollusk shells and the enormous diversity of pigment patterns they exhibit. The model is built around the general property of local excitation coupled with lateral inhi- bition common to most neural networks. A noteworthy feature in this model is that the same network architecture operates in both the spatial and time directions because the pigment patterns develop sequentially as the mantle lays down periodic increments of shell and pigment. Thus, the shell pattern records the complete time history of its neurosecretory activity. One might think of the pattern as an electroencephalogram, or the history of the thoughts of a mollusk! In general, waves propagating through a 3-dimensional neural network (e.g., a cortical column) have this same property: Local excitation/lateral inhibition extends laterally, as well as back- wards in space from where the excitation came, which is essentially backwards in time.

We now start to understand how mollusks may arrive at the bewildering variety of shapes and how variation within a taxon may occur. It opens up exciting new venues for further, evolutionary research.

Thanks to Nicole Webster, who mentioned this work during her talk at our internal Molecular Meeting and sent me the paper.

Reference:
Boettiger, A., Ermentrout, B. & Oster, G., 2009. The neural origins of shell structure and pattern in aquatic mollusks. - Proceedings of the National Academy of Sciences 106: 6837-6842.

Tags: literature, varia

The family Acavidae is a rare find in the Neotropics. This family may be found in the ‘Old World’ in Australia, Seychelles, Sri Lanka and Madagascar. And in Chile, where the genus Macrocyclis occurs with its sole species M. peruvianus (Lamarck, 1822).

This large species is up to 60 mm diameter. Although it is commonly known as the largest snail in the Chilean land snail fauna, its anatomy was hitherto unknown. Recently, da Silva & Thomé (2009) unveiled more details on the ecology and anatomy.


It was founds after a hard day of searching, under fallen logs near the vicinity of Lago Azul.



This is another case of Gondwanan distribution at the family level. It would be interesting to see if the affinities are confirmed by molecular evidence.

Reference:
da Silva, L.F. & Thomé, J.W., 2009. Macrocyclis peruvianus (Gastropoda, Acavidae), an endemic land snail from Chile. - Iheringa, Zoologia 99(2): 125-128.

Tags: Acavidae, Chile, Gondwana, literature

Tree snails in the Florida Keys have been studied for about a century now. They are a good subject to follow the fate of the different populations on different ‘hammocks’. Exactly what Fadely (2009) has done.

The study examined the past and present spatial distribution of the Florida tree snail, L. fasciatus solidus, in the Long Pine Key area of the Everglades National Park. Remote sensing and mobile GIS were used to create a GIS database of the field research results. Collection and survey-based data were used to create a current spatial distribution map of L. fasciatus solidus throughout the Long Pine Key area. The data collected during the 2006 survey were compared to a 1931 survey of the same study area conducted by Dr. William Clench of the Museum of Comparative Zoology (MCZ) of Harvard University. The data was used to determine the success of L. fasciatus solidus from 1931 to 2006, to evaluate a correlation between hammock size and the number of color forms, and to detect migration patterns of L. fasciatus solidus within the Long Pine Key area of Everglades National Park. Based on the average success rate for the seven color forms and the hammocks, the L. fasciatus solidus population in the Long Pine Key area
exemplifies one of a stable community. Each color form used for the analysis had a success rate between 67% and 100%. These percentages can only be the worst case scenario based on the fact that many Liguus were not observed, and any others that would have been observed, would only increase the success rate.



An interesting hypothesis is about the relation between the number of colour forms and the size of the hammock. The author supposed that there would be a linear relationship. However, as the figures show, this is clearly not the case. It is not evident from the data presented in his report to what extent re-introductions, migration and differences in data collection between the 1931 and 2006 surveys affect these results.

Reference:
Fadely, J.R., 2009. Population distribution of Liguus fasciatus solidus in Long Pine Key of Everglades National Park: i-xvi, 1-62. Thesis (M.Sc.), Florida Atlantic University, Boca Raton, Florida.

Tags: USA, Liguus, literature

In the context of the recent post on climate and snails, I received a copy of a very rare paper, although the author sounded familiar: the geographer and archeologist Alan Craig. The paper appeared in the journal "Andean Past" and was published in 1992.

Dealing with land snails in archaeological sites, my interest was raised by the paragraph on thanacocoenosis, or the massive accumulation of shells in certain areas. Referring to the case of Bostryx near Antofagasta, Chile (described here), Craig also mentions the massive occurrence of dead snails on the summit of Cerro Reque near Chiclayo, Peru. This is ascribed as the result of parasitation by a fly.
The observation is made that the cacti of the 'lomas' in Chile are replaced by bromeliads (Tillandsia) more northward in Peru. Craig suggests that aestivating snails on Tillandsia are carried from one 'lomas' area to another when the plants are "tangled in the fleece of guanacos". Interesting suggestion, but pure speculation...

The author clearly has a very limited oversight on the malacological literature, neglecting totally the work of e.g. Haas and Weyrauch on Peruvian snails. His figure 2 pictures "Strophocheilid tree snails" from Río La Leche, Lambayeque; these are probably a Thaumastus species. Also his other identifications are possibly erroneous, his Scutalus looks too small to be correct.

I would say: cobbler, stick to your last.

Reference
Craig, A., 1992. Archaeological occurrences of Andean land snails. - Andean Past 3: 127-135.

Tags: Chile, Peru, literature

Earlier on, I reported on a dispute in literature about snails in the desert near Antofagasta, Chile. Essentially, it was about the influence of the climate on shell shape. Hyperarid areas like the Atacama desert are a special habitat for snails and if unusual shell shapes are found it is very interesting.

Also in southern Peru snails may be found in the very arid coastal area.



This is a picture taken by Ralf Hesse near Nazca. A detailed shot reveals that here there are two forms present. The slender form resembles Bostryx hennahi (Gray, 1830), the stouter shells B. styliger (Beck, 1832).



It became interesting when I saw different photographs taken by him in the same area. These show that the latter species exhibits a transition to carinate forms; the latter resembles Bostryx reentsi (Philippi, 1851) known to occur slightly more southward near Chala.




This carination is hypothesized to be the result of ‘ecological stress’, in the case of the Chilean species by displacement through flooding or mud streams beyond the limits of their normal habitat. Indeed, there is reference in literature about climatic variability along the Chilean and southern Peruvian coast (Garreaud & Battisti, 1999; Vargas et al., 2006), due to the El Niño phenomenon.
Recently, studies have suggested that this mechanism also extended to the Nazca region during Pleistocene times (Eitel et al., 2005; Mächtle et al, in press). They hypothesize that a much more humid climate existed during the Pleistocene, with an increased aridification during the Holocene. Between 1000-1400 a semi-arid period would have occurred. The presence of loess in parts of the area on the flank of the Andes is an important argument in their papers. Radiocarbon dating of shells found amidst the loess dates this layer at ca. 10.000 yr BP. They postulate that the formation of the loess was influenced by monsoons crossing the Andes from Amazonia and leading to a higher precipitation.


Figure 3 from Mächtle et al. (in press), with the erroneous classification as Scutalus chiletensis granulatus Weyrauch; this is a species from N-Peru.

Hesse & Baade (2007) pointed out that an alternative explanation for the loess formation could be the fog vegetation occurring in coastal Peru and Chile (Garreaud et al., 2008). The occurrences of floods and debris flows has been recorded for the Ilo region in southern Peru (Keefer et al., 2003), but it may have also occurred in the Nazca region.

In conclusion, the occurrence of carinate shells with a transition to normal shell forms near Nazca is an interesting find. And although the evidence provided in literature points to floods and debris flows as a possible factor, more detailed research is needed to understand the mechanism of carination at play here.

References:
Eitel, B., Hecht, S., Mächtle, B., Schukraft, G., Kadereit, A., Wagner, G.A., Kromer, B., Unkel, I. & Rendel, M., 2005. Geoarchaeological evidence from desert loess in the Nazca-Palpa region, southern Peru: palaeoenvironmental changes and their impact on pre-Columbian cultures. - Archaeometry 47: 137-158.
Garreaud, R. & Battisti, D., 1999. Interannual (ENSO) and interdecadal (ENSO-like) variability in the Southern Hemisphere tropospheric circulation. - Journal of Climate 12: 2113-2123.
Garreaud, R., Barichivich, J, Christie, D.A. & Maldonado, A., 2008. Interannual variability of the coastal fog at Fray Jorge relict forests in semiarid Chile. - Journal of Geophysical Research 113: G04011.
Hesse, R. & Baade, J., 2007. Palaeoenvironmental changes in the Nazca-Palpa region, southern Peru--alternative interpretations of geoarchaeological evidence. - Archaeometry 49: 595-602.
Keefer, D.K., Moseley, M.E. & deFrance, S.D., 2003. A 38000-year record of floods and debris flows in the Ilo region of southern Peru and its relation to El Niño events and great earthquakes. - Palaeogeography, Palaeoclimatology, Palaeoecology 194: 41-77.
Mächtle, B., Unkel, I., Eitel, B., Kromer, B. & Schiegl, S., in press. Molluscs as evidence for a late Pleistocene and early Holocene humid period in the southern coastal desert of Peru (14.5⁰S) - Quartenary Research.
Vargas, G., Rutllant, J. & Ortlieb, L., 2006. ENSO tropical-extratropical climate teleconnections and mechanisms for Holocene debris flows along the hyperarid coast of western South America (17⁰-24⁰S). - Earth and Planetary Science Letters 249: 467-483.

Tags: climate, literature, varia, Peru

Some papers are very rare and hard to find. One of these is a publication on Hispaniola by Wetherbee & Clench (1987).

This paper was published a few years after the death of William J. Clench, as explained in the introduction. As it was privately published, it is very hard to find and seldom referred to. During the preparation of an upcoming paper on Hispaniola, I found it listed but failed to be able to locate it in any library.
As a last resource I wrote to Adam Baldinger (MCZ, Boston). He said it was present in their library and Samatha Edelheit, librarian, was so kind to send it by snailmail.

In 1891, Crosse published a catalogue of non-marine species of Hispaniola in the Journal de Conchyliologie. He listed 277 taxa, which are treated by Wetherbee & Clench in the Appendix to present-day species. A bibliography of malacological literature referring to the island completes the first part of this publication.
The second part is a brief biohistorical outline on the terrestrial Hispaniolan malacofauna. Starting in 1840 with a paper of Grateloup, a number of descriptors and collectors are mentioned.

Since the paper is so hard to get, I publish it here as a service. There are four parts: 1. Introduction, catalogue; 2. Appendix; 3. Bibliography; 4. History of early Hispaniolan malacology.

Reference:
Wetherbee, D.K. & Clench, W.J., 1987. Catalog of the terrestrial and fluviatile mollusk fauna of Hispaniola, and an history of early Hispaniolan malacology: i-iv, 1-89. Shelburne, Mass.

Tags: literature, West Indies

Are all changes a contribution to the advancement of science?

Today two messages from different sources interlocked in the end.
First, I read on the Taxacom discussion list an advertisement for a PhD-student. “Student should be curious, driven and excited enough about science that it is what they might choose to do were they to [do] win the lottery”. Lottery?? I was puzzled to see scientific work being compared to winning a lottery. Yes, I know that it is hard for scientists to find a proper job and, yes, it is sometimes a matter of good luck to have an application being granted. But is this so structural that you can speak of a lottery?
An hour later I incidentally found the paper of Lawrence (2009) and then I realized: it is becoming more and more a lottery! What started out many years ago as a way to stir up competition between scientists, has become a rather perverted system. Read Lawrence’s paper!

Science is like society in general: not every change is a good change. For sure, this one is not.

Reference:
Lawrence, P.A., 2009. Real lives and white lies in the funding of scientific research. - PLoS Biology 7(9): e1000197.

Tags: literature, varia

DNA barcoding is thought to be a method to ease species identification. Some even think that this method may make conventional taxonomy obsolete once techniques like Lab-on-a-chip are commonly used. Funding of barcoding projects is usually aimed at building a reference library. Any taxonomic problem-solving is seen as a useful by-product at most (Rougerie, Taxacom Discussion List).

With the above in mind, it was interesting to see a recent publication by Davison et al. (2009) on DNA barcoding in land snails. In this paper they report on a study to test the accuracy of barcoding on stylommatophoran species. As basis of the study the CO1 sequences deposited in GenBank were used; this test set represented 129 species, including a number of Neotropical species (Orthalicidae, Polygyridae). Stylommatophorans frequently show extreme divergence of mitonchondrial DNA.
The following results are noteworthy:
- barcoding correctly identified species in 92% of cases.
- optimum threshold value is 4%, but with an error rate of more than 30%; it is therefore recommended that barcoding is backed-up by phylogenetic methods and conventional taxonomy.


- intra-specific variation in stylommatophorans is genrally much higher than in other organisms.
- relatively many (> 25) samples of each species are needed if barcoding is to be effective, due to the rather extreme divergence of CO1 in land snails.

The results point to the conclusion that plenty specimens should be sampled to study the occurrence of different haplotypes in a species. When the species occurs in a broad geographical area, care should be taken to cover this area as much as possible. This may be an important point to have in the back of your mind when doing fieldwork. At the same time it may prove to be difficult to realize when sampling range-restricted or rare species. In those cases one is often glad enough to find just one or a few specimens. Any resulting barcoding should thus carefully evaluated.
Another important conclusion of this study is the recommendation that barcoding should be part of a suit of methods, including traditional morphological taxonomy, to study the intra- and interspecific variation in land snail species.


Reference:
Davison, A., Blackie, R.L.E. & Scothern, G.P., 2009. DNA barcoding of stylommatophoran land snails: a test of existing sequences. - Molecular Ecology Resources 9: 1092-1101.

Tags: methodology, literature, DNA

Brazilian non-marine snails are relatively well-known after the publication of Simone (2006). Still, it is interesting to see more detailed studies of parts of this vast country.

In the beginning of the year a paper appeared in Tentacle about Santa Catarina state by Agudo & Bleicker. Recently, Ignacio Agudo published several additional papers on land snails of States in southern Brazil. Several of these appeared in Ellipsaria, the newsletter of the Freshwater Mollusk Conservation Society in Illinois, USA. This newsletter, which is issued a few times per year, is a not-so-apparent journal for information on Neotropical land snails.
Although it may be useful to have records for species per state, it would even be more useful if precisely localities would be published. In that case the data could be used by later authors to build distribution maps or analyze the data. After all, a state may seem a small area when you map it on the scale of a big country like Brazil, from a snail’s perspective it’s still a huge area.



References:
Agudo-Padrón, A.I., 2009a. New malacological records from Paraná State, Southern Brazil region, with a general synthesys of current knowledge - Ellipsaria 11 (1): 11-13.
Agudo-Padrón, A.I., 2009b. New malacological records from Paraná State, Southern Brazil Region. II. Supplementary Annex. - Ellipsaria 11 (2): 6-7.
Agudo-Padrón, A.I., 2009c. Endangered continental mollusks of Santa Catarina State, Southern Brazil: An Overview. - Ellipsaria 11 (2): 7-8.   
Agudo-Padrón, A.I., 2009d. General mollusk fauna of Rio Grande do Sul State, Southernmost Brazil Region: a Preliminary Revision Rehearsal. II. New Bibliographical Records. - Ellipsaria 11 (2): 9-10.
Simone, L.R.L., 2006. Land and freshwater molluscs of Brazil. Sao Paulo: EGB, Fapesp.

Tags: Brazil, literature

Invasive snail and slug species are becoming more and more common in many countries. Although most may be introduced accidentally (Cowie & Robinson, 2003), if they are introduced these species can become problematic for e.g. agriculture, human health, the environment but may also endanger native species.

Cowie et al. (2009) just published a risk assessment for alien non-marine mollusc species that are of importance to the USA. There procedure might be applicable in other countries and their results lists many species that are generally considered as pests. In their procedure a ranking was made, using scores on biological and human-interaction attributes. The biological attributes include e.g. natural climatic range, phylogenetic relationships, adult size, egg/juvenile size, reproductive potential and breeding system. Human-interaction attributes are e.g. introduction pressure, invasion history, major pest elsewhere and economic potential. By summing up the scores a simple measure (S) of pest potential was attained. Dividing each S value by the number of attributes scores resulted in P values. The result is a ranking of all 46 species(-groups) considered, from high to low pest potential.



The results show a mixture of land and freshwater families, the latter often important because they are vectors for parasites. The ranking of the Succineidae is remarkable as they are generally not considered as significant pests, but they are now frequently found with horticultural imports (Cowie et al., 2008).
The number of Neotropical groups is rather limited; most groups have a wide-spread distribution. Orthalicids are not listed in this survey, possibly they are not (yet) a major quarantine issue in the USA.
The biology of invasive species still needs further research and also the interaction with plant ecosystems is virtually unknown. Despite the many efforts by Cowie and others, there remains more than enough to do for curious minds...


References:
Cowie, R.H. & Robinson, D.G., 2003. Pathways of introduction of nonindigenous land and freshwater snails and slugs. - In: G. Ruiz & J.T. Carlton (eds.) Invasive species: vectors and management strtategies: 93-122. Island Press, Washington DC.
Cowie, R.H., Hayes, K.A., Tran, C.T. & Meyer III, W.M., 2008. The horticultural industry as a vector of alien snails and slugs: widespread invasions in Hawaii. - International Journal of Pest Management 54: 267-276.
Cowie, R.H., Dillon jr, R.T., Robinson, D.G. & Smith, J.W., 2009. Alien non-marine snails and slugs of priority quarantine importance in the United States: a preliminary risk assessment. - American Malacological Bulletin 27: 113-132.

Tags: literature, varia

A few more papers appeared in print yesterday, all in Dutch this time. They are published in Spirula, a periodical of the Dutch Malacological Society. However, two have English summaries and those of you who regularly follow this blog will recognize the topics.

The first paper is my laudatio for Dolf van Bruggen during the celebration of his 80th birthday. I take the opportunity to put up a picture here that was taken during that ceremony.

Dr. Dolf van Bruggen during his closing word. On the right-hand side Dr. Hans Kuiper, one of the other Honorary Members of the Dutch Malacological Society (Photo: Ton de Winter).

The second paper is on the putty eating snails that I mentioned in this post. And finally, there is a paper on my Suriname project.

Tags: publishing, literature

My recent publications in the Festschrift for Dolf van Bruggen are now available online at the journal’s website.

Tags: publishing, literature

It has been a while ago that I wrote on the Biodiversity Heritage Library and how it can change the access to literature.



When I looked it up earlier this week, I was positively surprised to see the change the site has made. Not only their holdings on molluscan literature has grown to 605 titles (some of them multi-volumes ones), the quality of the text has also been greatly improved.
The is also a large number of periodicals available, some of them rarely found, even in the a good museum library.

If you are looking for some of the major works of the Giants, you should certainly consult this site.

Tags: literature

Conservation issues are gaining more and more attention. But it always the question if the academia are researching subjects that matter to practitioners and policy-makers. Sutherland et al. (2009) have addressed this gap and set up a process to identify scientific questions that, if answered, would have the greatest impact on conservation practice and policy.

Through a Delphi-approach they boiled down the initial list of 2291 questions to 1655, which were prioritized at a 2-day workshop of the participants. The resulting 100 questions are divided into 12 sections: ecosystem functions and services, climate change, technological change, protected areas, ecosystem management, organizational systems and processes, societal context and change, and impacts of conservation interventions.

Looking at this list from the viewpoint of a natural history museum researcher (not pretending an university), the first theme appeals. “Key research areas include investigating which components of biological diversity are essential for providing ecosystem services, ...”. The first question certainly seems relevant to me: “Do critical tresholds exist at which the loss of species diversity, or the loss of particular species, disrupts ecosystems functions and services, and how can these tresholds be predicted?”.
The last part of the question reminds me of a recent book published by Marten Scheffer, Critical transitions in nature and society. If you have time to look at the video of his lecture at the Stockholm Resilience Center in 2007 (54’, also available as audio file), you certainly should do. Very interesting...

Another interesting questions is in the theme Climatic change: “Which elements of biodiversity in which locations are most vulnerable to climatic change, including extreme events?”. I think a interesting potential example is the topic that I posted yesterday.

If you would like to see the remaining 98 questions, you can consult the paper here. But be warned, it is at a relatively high abstraction level compared to the usual topic of this blog.

Reference:
Sutherland et al., 2009. One hundred questions of importance to the conservation of global biological diversity. - Conservation Biology 25: 557-567.

Tags: conservation, literature

Conservationists may be alarmed (again), although it doesn’t concern a charismatic or a flagship species. It’s about the ecosystem of the tepuis. And, although the threat is not immediate, it is a serious one.

Valentí Rull has written, alone or together with members of his research group, many papers of interest about the Guayana Shield (Pantepui). Recently, one more appeared dealing with the potential effects of climate change on the tepui ecosystem. By modeling the shift of the biotas due to temperature rises of 2 and 4 degrees, they calculated the effects on the vascular plants. Evidence is provided that up to 45% of Pantepui species may be endangered with extinction due to habitat loss before the end of the century, if the temperature rises with 4 degrees.



The bromeliads in which snails have been found are on the list of species involved. The ecological ties between plants and snails may turn out unfavorable for the snails, given the fact that they are only occurring on the upper part of the tepuis and these communities are bound to be affected. Due to the flatness of these mountaintops there will be no escape...

Reference:
Nogué, S., Rull, V. & Vegas-Vilarrúbia, T., 2009. Modeling biodiversity loss by global warming on Pantepui, northern South America: projecting upward migration and potential habitat loss. - Climatic Change 94: 77-85.

Tags: Venezuela, tepui, climate, literature

A colleague from our library sent notice about a new bibliographic tool. It is called Mendeley and it allows you not only to organize your literature, but also find new publications, share them with others who have the same interest and see trends based on statistics. Besides a desktop client, it is also a tool that allows you to have your own library anywhere on the world at the click of your mouse. Provided that you are in a place with access to the internet, of course.

The software is currently version 0.6.5.1 and is far from perfect. When I tried it, importing over 1600 PDFs, more than 25% had errors in the metadata. Therefore, it might be preferable to import via EndNote or BibTex, if you have one of these (I haven’t). It seems advisable to correct all the errors before one starts to share references with peers. Otherwise it will be a large hump of junk.
As with many new tools you have a considerable learning curve before it is really beneficial and enhances your productivity. However, it is an interesting tool and surely woth closely following its development.

The trend is clear....online, online, online whatever can be done that way. Some interesting news ahead...

Tags: literature, methodology

The first comprehensive scientific overview of the non-marine molluscs of continental Ecuador was published at the end of the 19th century (Cousin, 1887). More than a century later this introductory book to land and freshwater snails from this country appears. As the author writes, it is “an integral study on the biodiversity ..., and includes a characterization of the principal families and genera”.

After the introduction there are eight chapters. The first chapter gives a historical overview on malacology in Ecuador. The description of the current situation reveals that there is hardly malacological work being done at the moment, and the collection in the natural history museum in Quito is under revision. The second chapter lists the families (32) of land and freshwater molluscs, including bivalves. A key to families is included. Chapter 3 provides a short introduction to terrestrial snails. The following chapter presents a more elaborate characterization of the families of land snails, their habitat, ecological importance, experiences with rearing under laboratory conditions, geographical distribution and occurrence in Ecuador. There are many pictures of shells and living animals. Chapter 5 and 6 repeats the same scheme for freshwater molluscs. The final two chapters give an analysis of the biogeography, dividing the country into seven regions. In the Annexes, several maps are added.



This book is clearly aimed at a rather broad public of people with an interest in molluscs. As stated before, no introductory text to this group was available for Ecuador and the book clearly serves this aim. From a scientific point of view, there are several points which could be improved; e.g. not all literature mentioned in the text is included in the list of references and there are several typos. Hopefully there will be enough demand to make a second, revised edition possible.
The author has spent many years to gather all the data and made field observations that are worth to be included in a book like the ones for Cuba or Brazil (see literature). Despite lack of funds and difficult conditions (the production of the book took several years!), it is thanks to the perseverance of the author that this book has finally resulted.


References:
Correoso Rodríguez, M., 2008 [2009]. Los moluscos terrestres y fluviales del Ecuador continental. La biodiversidad desconocida: 1-179. - SIMBIOE, Quito. ISBN 978-9978-9959-1-4.
Cousin, A., 1887. Faune malacologique de la république de l’Equateur. - Bulletin Société Zoologique de France 12: 187-287.

Tags: literature, Ecuador

Today a paper was published which may possibly be seen as a milestone in online publishing of taxonomic works (Miller et al., 2009a). It is not about Neotropical snails; it is not even about snails. It is about Chinese spiders. Why then bother in this blog?
While the future of taxonomy seems with online publication, there is much debate about it and more and more taxonomists have a preference for journals that are freely accessible (Penev et al., 2008). Until now, however, an example was lacking following a clear framework and tackling some of the remaininbg stumble-blocks (e.g. the poor quality of GBIF data). Penev et al. (2009) now propose the following scheme, which is used in the open access journal of ZooKeys.


Jeremy Miller, first author of the underlying taxonomic work, showed me last week already the datasets (Miller et al., 2009b, c) and how they worked. Especially the link with Google Earth is very nice, with data on the species showing up when the locality pin is clicked upon. A link to MorphBank is included, in which pictures of the species are stored.



This model provides a good methodology for online publication, while assuring at the same time that the data are of high quality and freely accessible.

References:
Miller J.A., Griswold C.E., Yin C.M. 2009a. The symphytognathoid spiders of the Gaoligongshan, Yunnan,
China (Araneae, Araneoidea): Systematics and diversity of micro-orbweavers. - ZooKeys 11: 9-195. doi: 10.3897/zoo-
keys.11.160
Miller J.A., Griswold C.E., Yin C.M. 2009b. Appendix B. Locality data (XLS format) for all specimens of the
spider families Th eridiosomatidae, Mysmenidae, Anapidae, and Symphytognathidae collected during an inventory of
the Gaoligongshan, Yunnan, China, 1998-2007. DATASET. File format: Microsoft Excel (1997-2003). doi: 10.3897/
zookeys.11.160-app.B.dt. - ZooKeys 11: 9-195. doi: 10.3897/zookeys.11.160
Miller J.A., Griswold C.E., Yin C.M., 2009c. Appendix C. Locality data (KML format) for all specimens of the
spider families Th eridiosomatidae, Mysmenidae, Anapidae, and Symphytognathidae collected during an inventory of
the Gaoligongshan, Yunnan, China, 1998-2007. DATASET. File format: KML (Keyhole Markup Language) version
2.1 for GoogleEarth. doi: 10.3897/zookeys.11.160-app.C.dt. - ZooKeys 11: 9-195. doi: 10.3897/zookeys.11.160
Penev L., Erwin T., Thompson F.C., Sues H-D., Engel M.S., Agosti D., Pyle R., Ivie M., Assmann
T., Henry T., Miller J., Ananjeva N.B., Casale A., Lourenco W., Golovatch S., Fagerholm H-P.,
Taiti S., Alonso-Zarazaga M., 2008. ZooKeys, unlocking Earth’s incredible biodiversity and
building a sustainable bridge into the public domain: From “print-based” to “web-based”
taxonomy, systematics, and natural history. ZooKeys Editorial Opening Paper. - ZooKeys 1:
1-7. doi: 10.3897/zookeys.1.11
Penev L., Erwin T., Miller J., Chavan V., Moritz T., Griswold C., 2009. Publication and dissemination of data-
sets in taxonomy: ZooKeys working example. ZooKeys 11: 1-8. doi: 10.3897/zookeys.11.210

Tags: publishing, literature, methodology

There is some debate now on the TaxCom mailing list about the recent publication of Costello (2009). His paper argues that biodiversity data should be published online, but that “scientists’ concerns about these efforts have not been answered and initiatives to motivate scientists to comply have been inadequate”.

It cannot be denied that online publication can be a powerful tool and there are several nice examples that could be mentioned. To name just a few that I have recently accessed: Gary Rosenberg’s site on Jamaican molluscs and the World Spiders Catalog, maintained by Norman Platnick. [No, I’m not switching from malacology to arachnology...]. These are sites made and maintained by individual specialists; besides these selective exemples, many more could be cited. My impression is that quality is excellent to good and possibly the main caveat is that, after a while and for whatever reason, the site is no longer updated.
The other extreme are sites (or rather portals) than host a huge amount of data and make these available for further use. A well-known example is the Global Biodiversity Information Facility (GBIF). Unfortunately, it is also this example that shows the pitfalls of these data centers. As far as my specialism is concerned, the data is notoriously unreliable. It is also outrageously incomplete. And that’s one of the main points of Costello’s critique: many primary data, which were gathered using public funds, are not available through data centers for further research and several other benefits that are listed in his paper.


His proposal is to drastically alter the way scientists publish their data, moving them from print to online data centers.


There are several useful suggestions made in his paper to motivate people for online publication, e.g. to stimulate the use of giving credit to authors who upload data, to facilitate the use of tools (such as Scratchpads) and requirements by funding agencies.
The advantages of online publication are clear. However, I feel that we still have a long way to go. To name a few of the remaining stumble blocks: quality checking, involvement of scientific amateurs (who also generate primary data) and to re-think the business model that sustains now many societies that issue scientific journals. Not all publications are commercial and hence publishing data as such can have adverse effects which have not been mentioned so far.

I know, there is much more that can be said about this topic...

Reference:
Costello, M., 2009. Motivating online publication of data. BioScience 59: 418-427.

Tags: publishing, literature

Yesterday in Naturalis museum we had a special meeting to honour two colleagues who got their Ph.D. a few months ago. I will mention briefly here the work of Frank Wesselingh, as his thesis* is related to the Neotropics.



His research centered on the Pebas formation in eastern Peru and northwestern Brazil and relates to the freshwater molluscs found as fossils.
When he started his research, only pollen data were known that spanned a couple of million years. Studying the snails, he found many new species and some new genera (see references in Wesselingh, 2008; or his personal page at Naturalis). All but one species are now extinct.



As the above pictures shows, his results allowed him to study the landscape evolution of western Amazonia. This is highly relevant, also to land-snails, as it may provide evidence about e.g. the connections between the Andes and the Guayana Shield.

Later this year a book will be published in which this topic will be elaborated.

Reference:
Wesseling, F.P., 2008. Molluscan radiations and landscape evolution in Miocene Amazonia. - Annales Universitates Turkuensis, 232: 1-41. Thesis defended 21 February 2009.

Tags: Peru, Brazil, geology, literature

During a literature survey on Liguus, I came across a report (Diaz et al., 2006) that was published some years ago. It is the result of a joint Cuban-American assessment of the biodiversity in part of the province Camagüey in east Cuba, the Sierra de Cubitas.
Malacology is but a small part of the results, for which field observations were made during four days in September 2002. The only picture of snails is, however, from Liguus fasciatus.



It is a new record for the Sierra de Cubitas and together with another new record for Steatocoptis bioscati, the total number of molluscs for the area is 50.
When I glanced through the report, my eyes caught some interesting sentences related to Opisthosiphon (Annulariidae). Four species of this genus occur in the Sierra de Cubitos: O. banoense, O. evanidum, O. greenfieldi, and O. obturatum. “Individuals of the four species were seen copulating with one another and I was able to determine that females always have a pattern of dark stripes on their shells, while the males have pale or dark shells without those stripes.” The authors add that this observation should serve as a starting point for a taxonomic review of the genus.
It is precisely observations like this which can only be made in the field and which make these reports special. A little gem found, that I wanted to pass on to you.

More reports from the same series, covering also other Neotropical countires, can be found here. However, not all contain data on molluscs. Actually, only a few others related to Cuba...


Reference:
Díaz, L.M., Alverson, W.S., Barreto, A. & Wachter,T., 2006. Cuba: Camagüey, Sierra de Cubitas: 1-180. Rapid Biological Inventories Report 08. The Field Museum, Chicago.

Tags: Cuba, Liguus, literature, biodiversity

What can we learn from traditions? Today I may have learned a tool that has proven to be useful and passed from one generation to the following. In a sense, survival of the fittest.

My colleague Menno Schilthuizen draw my attention to a useful technique for preserving live collected animals (see also my previous post on a similar, but possibly less effective technique). It was presented during a symposium on micro-molluscs at the WCM in Antwerp. I admit, I skipped this subject at that time, but this particular topic seems very useful. Fortunately, the papers from this symposium have already been published and the methodology is one of them. It is called niku-nuki. The essence is to quickly kill the animal and preserve the shell.



While normally it can be difficult to preserve the animal without tissue degradation, this method promises soft tissue preservation both for DNA and anatomical research, plus an undamaged shell. It consists of four relatively simple steps: 1. Put the animals in a vial and when they actively move around on the bottom kill them by pouring boiling hot water over them (A). 2. Separate the columellar muscle from the shell by pinching the animal and gently pulling it (B). 3. Unscrew the body from the shell (C). 4. Wash and dry the shell and fixate and preserve the soft parts (D).

Fukuda et al. (2008) describe the method in any detail for different groups. Although their method is especially geared to smaller species, it should be worthwhile to try also on larger ones.


Reference
Fukuda, H., Haga, T. & Tatara, Y., 2008. Niku-nuki: a useful method for anatomical and DNA studies on shell-bearing molluscs. - Zoosymposia 1: 15-38.

Tags: methodology, literature

Central American land snails are not frequently the subject of a publication. But in the latest issue of Iberus, the journal of the Spanish malacologists, there is a paper by Pérez and others on Euglandina obtusa (Pfeiffer, 1844). The species is hitherto only known from the type locality in Nicaragua.



The authors redescribe the shell of this poorly known species and add 15 new localities, all in the south-western part of Nicaragua.
As some localities are at the border of Honduras, I wonder how the authors can be sure that this species is a truly endemic of Nicaragua? Snails don’t mind administrative borders...


Reference
Pérez, M.A., Altonaga, K. & López, A., 2008. New data on the morphology and distribution of Euglandina obtusa (Pfeiffer, 1844) (Gastropoda: Spiraxidae) a Nicaraguan endemism. - Iberus 26: 127-131.

Tags: Spiraxidae, literature

The Neotropical succineid systematics “is permeated with misconceptions and contradictions” (Arruda & Thomé, 2008)*. It is one of those groups which are often identified on the basis of their anatomy; the Veronicellidae - specialism of the second author - is one of the others.

In their paper two species of Omalonyx, occurring partially sympatrical, are untangled using both morphological and anatomical characters.

This paper is an example how laborious it can be to know with which species you may be dealing. There are many similar problems to be solved within this family, which has a broad Neotropical distribution.


Reference:
Arruda, J.O. & Thomé, J.W., 2008. Revalidation of Omalonyx convexus (Heynemann 1868) and emendation of the type locality of Omalonyx unguis (Orbigny 1837) - Archiv für Molluskenkunde 137: 159-166.

Tags: literature, Succineidae

Today the new number of Tentacle appeared, the once-a-year newsletter of the IUCN/SSC Mollusc Specialist Group. As I like their old logo better than their new one, I will use it here again.


In issue 17 several interesting papers appear:
- Malacological research in the Serra do Tabuleiro Ecological Park, Santa Catarina, Brazil: Ignacio Agudo and Mario Bleicker report on the malacofauna of this - also geologically - interesting area. There are 44 land and freswater species known, of which 7 invasive pest species; of the native tree snails three are Orthalicoidea.



- Land snails as indicator species: Timothy Pearce reports on disturbances of complex ecosystems and the usefulness of molluscs to signal these disturbances by their presence.
- Assisted colonization to save terrestrial gastropods threatened by climatic change: Aydin Örstan elaborate on recent proposals to move species threatened by extinction in their native habitat. This is like opening up a big Box of Pandora, with lots of philosophical questions too. Which species to select and why? How far should they be moved? How dissimilar may their new habitat be? What if there is no comparable habitat available? Think of the tepui land snails... The whole idea sounds a bit like Noach’s Ark to me. But who will be Noach and who will be God?
- Conservation status of an endemic Cuban land snail: Cuba has a high number of endemic snails, of which many are endangered. David Maceira et al. report on a species from the eastern side of the island that is seriously threatened by habitat fragmentation.



- Conservation status update on Society Island Partulidae: this is an interesting paper because it shows how foresight may pay off several decades later. John B. Burch collected back in the ’70s at the Society Islands, sent animals live to the USA where they were freeze-dried long before DNA sequencing had become to mind. Thanks to this effort it is now possible to have molecular studies of populations that have become extinct since that time.
- Finally, there is a paper by Francisco Borrero, Carl Christensen, Modest Correoso, Valentín Mogollón and myself on the further spread of Lissachatina fulica in South America. It seems a matter of time only before this species is reported from the next new occurrence.

In all, an interesting new issue and glad to see that several Latin American authors have found this medium as a way to raise attention to Neotropical snails.

Tags: literature

Very recently the long-awaited, second paper of Dai Herbert on Prestonella was published. It provides molecular evidence of the bulimulid relationships of the genus.



The most surprising aspect is the close relation between Prestonella and the Australasian members: the clade of Prestonella, Bothriembryon and Placostylus appears to be monophyletic and well supported (BP=100%).

Also the morphological data support a strong affinity between Prestonella and the other members of the Orthalicoidea: the genitalia, the palleal organs, the holopodous foot and the shape and sculpture of the protoconch.



This paper is the first confirmation of the classical, tri-continental distribution of the Orthalicidae.

Interestingly enough, another paper appeared recently that also sheds some light on the relationships of the Orthalicidae. Uit de Weerd (2008) primarily studied the relationships of the Urocoptidae, but from his molecular analysis it is clear that Coelocion from Australia is also related, as is shown in this part of his figure 4.



The unknown unknowns shift constantly and each study turns part of them into known unknowns. We are making progress, slowly but very steadily...

References:
Herbert, D.G. & Mitchell, A., 2009. Phylogenetic relationships of the enigmatic land snail genus Prestonella: the missing African element in the Gondwanan superfamily Orthalicoidea (Mollusca: Stylommatophora). - Biological Journal Linnean Society 96: 203-221.
Uit de Weerd, D.R., 2008. Delimitation and phylogenetics of the diverse land-snail family Urocoptidae (Gastropoda: Pulmonata) based on 28S rRNA sequnece data: a reunion with Cerion. - Journal Molluscan Studies 74: 317-329.

Tags: literature, South Africa, Prestonella

Decline of malacological populations is not limited to the Neotropics. It is part of a global pattern and, although we may have to accept it, it has not to go unnoticed.

Christine Parent has written a small paper earlier this year about this topic. She explains in clear writing what role molluscs play in ecosystems and why it is important to stop their decline.

No doubt that many of my readers may be aware of the existence and the urgency of this problem. But it cannot be stressed enough, so I pass on the reference.

Reference
Parent, C.E., 2008. The global decline of mollsuks. ActionBioscience.org

Tags: conservation, literature

While searching some literature on Chile for a friend, I found an interesting paper on the ecology of a Bostryx species from the desert in the northern part of the country. It also sheds some new light on the phenomenon of carianation (subject of an upcoming paper) and relates to the specialization / speciation discussion briefly summarized here and here.

In 1970, the paleontologist Herm described a new species, Bostryx variabilis, from Pleistocene marine sediments near Antofagasta.


Map showing the area just north of Antafagasta (from Herm, 1970)

To explain the occurrence of this terrestrial species amidst marine facies, he postulated a sea level regression-transgression. The species is carinated (keeled) and partially uncoiled.



In 1981, Alan Craig -a geographer- did field work in the same region and made some observations which questioned Herm’s hypothesis. He found many specimens of B. variabilis in nearby localitions, but they were restricted to places where also fossilized lichens occurred. Moreover he found transitions to a Recent species, B. mejillonensis (Pfeiffer, 1857).

Isotopic dating yielded an age of 2180 +/- 50 yr B.P., making the Pleistocene sea level change as postulated by Herm unnecessary for the type locality.
But how to explain the occurrence of B. mejillonensis-variabilis at this place? Eventually it appeared that Bostryx mejillonensis was only found in localities where meteorological circumstances sustained epiphytic colonies of lichens on cacti at the top of a hill nearby the type locality of Herm. At the slopes below the elevation where the seasonal fog banks have influence, the hyperarid desert constitutes a barrier for the dispersal of snails. The hill top thus forms an ecological island. This finally led Craig to hypothesize that B. mejillonensis had been forced outside their habitat into the surrounding desert from where they were unable to escape. Rapid changing environmental conditions would have ‘stress-induced’ a speciation process which led to the aberrant form of B. variabilis. Support for this hypothesis were field observations by Craig of runnels, caused by occasional winter rains, leading to downslope transportation of snails.


Area just north of Antafagasta with the localities mentioned by Herm (1970) and Craig (1985) indicated. The distribution area of lichens indicated by Craig marked on Morro Moreno in white (source: Google Earth).

Given the hypothesis briefly outlined above, my question is: is carination as observed in other places (e.g., here and here) also best explained as a ‘stress-induced speciation process’? If so, are there analogous ecological circumstances that force snails to transform into aberrant, carinated and -sometimes even - uncoiled shells?

References:
Craig, A.K., 1985. Speciation and age revision of the Atacaman snail Bostryx variabilis Herm. - Quarternary Research 23: 382-387.
Herm, D., 1970. Bostryx variabilis n.sp., eine Landschnecke aus dem Altpleistozän von Mejillones, Nordchile. - Mittheilungen Bayerischen Staatssammlung Paläontologie und historische Geologie 10: 189-198.

Tags: literature, Bostryx, speciation, Chile

This qualification is given to Easter Island, an island that politically speaking belongs to the Neotropics (it is part of Chile). Jared Diamond used Easter Island as one of the cases in his book Collapse (2004), in which he illustrated how ancient cultures vanished and how modern cultures are vulnerable for it. (I propose you look at this review, written in 2005, to read some context for the current situation).


There is a comprehensive review of the terrestrial mollusks by Boyko & Cordeiro (2001), who list six species. Most of them are more or less cosmopolitan species and introduced by human activities. Only Pacificella variabilis Odhner, 1922 is confined to the Pacific.
Now there is a new paper by Kirch et al.* on the malacofauna of this island, for which malacological reports are scarce. The authors not only report three additional introduced species, but also describe a subfossil new endemic one: Hotumatua anakenana gen.nov, spec.nov.



Although Easter Island has now only a very impoverished land snail fauna, Kirch et al. suspect that the island once had a much richer terrestrial fauna. This paper is evidence of that fact.

References:
Boyko, C.B. & Cordeiro, J.R., 2001. The terrestrial Mollusca of Easter Island (Gastropoda, Pulmonata). - Basteria 65: 17-25.
Diamond, J., 2004. Collapse. North Point Press, New York.
Kirch, P.V., Christensen, C.C. & Steadman, D.W., 2009. Subfossil land snails from Easter Island, including Hotumatua anakenana, new genus and species (Pulmonata: Achatinellidae). - Pacific Science 63: 105-122.

Tags: taxonomy, literature

Continuing the series on new species, I realized it be better called new taxa in order to include also supraspecific new introduced names.

Today a number of such names, introduced by Thomas Watters for the Annulariidae. This family of land snails is huge, with about 1400 nominal taxa described of which Watters retains ca. 700 as valid species. The distribution is focussed on the Caribbean, with some groups occurring in Florida, Central American and northern South America.




From top to bottom: Blaesiospira echinus (Pfeiffer, 1864), Chrodropomartes irradians (Pfeiffer, 1852), Xenopoma hystris (Pfeiffer, 1862).

New taxa:
Tudorinae subfamily nov.
Chittypoma gen.nov. Type species: Adamsiella jarvisi Henderson, 1901
Goulidipoma gen.nov. Type species: Chondropoma callipeplum Solem, 1961
Halotudora gen.nov. Type species: Cyclostoma radiosum Morelet, 1849
Megannularia gen.nov. Type species: Turbo pulcher Wood, 1828
Samanicola gen.nov. Type species: Incertipoma nesiotes Bartsch, 1946
Saulaepoma gen.nov. Type species: Cyclostoma sauliae Sowerby, 1843

His work is a milestone for this - often considered as difficult - family, giving a new scheme for the higher taxa and references to taxa on the species level. For the latter the following data are provided: depository of types, type locality, if the type has been figured, current taxonomy, remarks, synonymy, distributional range and etymology.
The only thing I was missing is an index.

Reference:
Watters, G.T., 2006. The Caribbean land snail family Annulariidae: a revision of the higher taxa and a catalog of the species. Leiden: Backhuys Publishers, 557 + 9 unnumbered pages + appendix (3 pp.).

Tags: taxonomy, literature

The Streptaxidae are a family known from various tropical regions and Barbosa et al. (2008) have now re-evaluated a Brazilian group, the genus Hypselartemon Wenz, 1947.


It is a nice paper, dealing with the morphology and anatomy of the few taxa placed in this genus. Formerly ascribed to Brazil and Colombia, these taxa are now wholly restricted to the former country and occur in the eastern part only.

Reference:
Barbosa, A.F., Salgado, N.C. & Santos Coelho, A.C. dos, 2008. Taxonomy, comparative morphology, and geographical distribution of the Neotropical genus Hypselartemon Wenz, 1947 (Gastropoda: Pulmonata: Streptaxidae) - Malacologia 50: 1-12.

Tags: Brazil, literature

Darwin’s legacy is still very vivid and doubtless will continue to be. A recent paper by Parent et al. (2008) reviews the colonization and diversification of the Galápagos terrestrial fauna. Snails are one of the groups that have diversified on this archipelago. Of the 10 land snail genera present on the islands, only the bulimulids show a huge radiation. Much is, however, still unknown - not only of snails but also of other groups - and e.g. even the sister group of the Galápagos bulimulids has not been ascertained till now. One of the reasons is that no reliable molecular clock for the group is known. As a non-vagile group, land snails are among the animals for which many single island endemics are to be expected. Parent & Crispi (2006) found a combination of both within-island and between-island speciation and the relative importance of genetic drift and selection in within-island diversifications of this group is not known.
While the speciation processes are affected by colonization and extinction, the geographical dynamics of the whole archipelago has to be taken into account, where change of sea levels undoubtedly created or ceased possibilities for gene flow.
The analogy with the tepui ‘islands’ in Guayana are strikingly. Perhaps I will come back at this issue later, when hopefully more phylogenetic data are known.






Incidentally I came across another paper on the Galápagos earlier this week (Estes et al., 2000). It is a detailed reconstruction of the journey of Darwin within the archipelago. Where was Darwin in the Galápagos and what did he see? Based both on bibliographic sources and revisiting the islands in the same period of the year, the authors were still able to see the geological features noted by Darwin. However, in contrast, the flora and fauna has changed considerably since the Beagle landed on the islands.
The reconstruction was possible thanks to the detailed field notes taken during that expedition and the fact that they have been preserved. Again and again, I cannot help to stress the importance of taking field notes and storing them at a place where they will be available for future scientists.

References:
Estes, G., Grant, K.T. & Grant, P.R., 2000. Darwin in Galápagos: his footsteps through the archipelago. - Notes and Records of the Royal Society London 54: 343-368.
Parent, C.E. Caccone, A. & Petren, K., 2008. Colonization and diversification of Galápagos terrestrial fauna: a phylogenetic and biographical synthesis. - Phliosopical Transactions of the Royal Society, B 363: 3347-3361.
Parent, C.E. & Crespi, B.J., 2006. Sequrntial colonization and diversification of Galápagos endemic land snail genus Bulimulus (Gastropoda, Stylommatophora). - Evolution 60: 2311-2328.

Tags: Ecuador, literature, speciation , biohistory

As always, it is a very good idea to publish a catalogue of type material in a museum. The initiative of three ladies to list the types from the Zoology Museum of the University of Costa Rica deserves special attention, as it is still one of the few examples of publications on type depositories from Latin American museums.

The publication mainly lists marine taxa and land snails are represented by type material of Helicina species described by Ira Richling. The accompanying photographs are of good quality, but for a colourful impression of the helicinids one should consult Richling’s papers.
Unlike many major museums in the USA en Europe, the majority of the collection in this museum is preserved in ethanol.

Reference:
Villalobos-Rojas, F., Guzmán-Mora, A.G. & Camacho-García, Y.E., 2008. Catalogue of the type material of mollusks deposited at the Zoology Museum, University of Costa Rica. - Nautilus 122: 155-165.

Tags: types, literature

In a thorough paper, Hearty & Schellenberg present the results of their chronostratigraphic work on Cerions from the Bahamas. With their study object they follow in the footsteps of Goodfriend and Gould, to name just a few well known. As such that is no story for success. I recall a co-student to do morphometric studies on Cerion uva from the collections of P. Wagenaar Hummelinck, only to conclude after measuring thousands of specimens that the uniformity of the populations on Aruba, Curacao and Bonaire is most strikingly.

With modern techniques Hearty and Schellenberg were able to resolve stratigraphic subunits with the Holocene and late Pleistocene of fossil and living Cerion from San Salvador Island. Morphometric studies on samples spanning a 140 kyr time period revealed interglacial sequences with a trend to increasing shell size.


Their detailed study is not only a nice contribution from a geological viewpoint, it also shows that a fossil record might be necessary to reach the conclusions they were able to draw. Their time-succession shows a continuous and directional morphological change on island-wide scale. The period of greatest rate of change coincides with the onset of interglacials, which hints to the availability of a richer diet, resulting in faster growing, more globose shells. One of their working hypothesis for future studies is that ecophenotypy as an evolutionary mechanism may explain the temporal changes in shell shape.

A second study on fossils, this time from the Mediterranean, is the paper by Altaba on Balearena from Mallorca. There are some similarities: it also considers an island fauna, and also applies morphometrics. Yet there is an interesting difference in methodology. Altaba uses geometric morphometrics applying landmarks and a principal component analysis. I find his analysis more appealing.

For the analysis he uses the program PAST, which is probably better known amoung paleontologists than amoung taxonomists working on recent specimens. I found it an interesting freeware program, albeit working only under Windows. The cross-platform alternative is MorphoJ and the acquiring of landmarks can be done use ImageJ, either from photos or drawings. As usual, my preference is platform independent software.

References:
Altaba, C.R., 2007. A new genus and species of Enidae (Gastropoda: Pulmonata) from the Quartenary of the Balearctic Islands (Western Mediterranean). - Zootaxa 1595: 43-52.
Hearty, P.J. & Schellenberg, S.A., 2008. Integrated Late Quartenary chronostratigraphy for San Salvador Island, Bahamas: patterns and trends of morphological change in the land snail Cerion. Palaeo3 267: 41-58.

Tags: Cerion, Bahamas, literature, methodology

Science journalists usually have a good sense of appealing news. This week a brief article in my newspaper draw my attention to an upcoming paper by Devictor et al. in the Proceedings of the Royal Society B, december 2008. The caption is: French birds breed more northerly but the climate [change] is faster.
We have read more often about the changes in the fauna and flora due to the warming of the climate of course. Some are good and (most) others are bad. So far I haven’t read much about snails; most is about plants, insects and birds. Anyone busy sorting out the effects on snails?

A quick search in Scholar shows that Devictor has a track record on the subject. Incidentally a precursor to the same paper can be found under the title “French birds lag behind climate warming”, already posted on 29 October 2007 in Nature Precedings. The basis of the paper is the Community Temperature Index, a measure calculated as the average of individual species temperature index (STI) per assemblage on a site. CTIs are then determined by the long term average temperature experienced by breeding birds over their (European) range. These can be calculated from the Worldclim database, taking the average temperature during the breeding season and coupling these data to spatial distribution data.

The effect of climate change on shifts in flora and fauna in the Neotropic/Nearctic region is not readily in the news here. But my guess would be that a similar phenomenon occurs in Mexico and the USA. Is this effect also noticeable in the ranges of land snails? Could it perhaps be measured analogous to the way briefly summarized for birds above?
Not sure if there any data exist on the occurrences of species assemblages of land snails in southern USA. I remember to have seen a map with grids somewhere, but don’t recall where. Anyway, if the snails go North they will surely lag behind the climate warming. At a snail’s pace...

Tags: climate, literature

An extension of my post from yesterday.

There are three hypotheses formulated by Harrison et al. which I will repeat here for the sake of clarity. The question is how ‘naturally rare species’ () have persisted through evolutionary time, and whether particular characteristics have enabled them to avoid extinction in spite of their small ranges, low abundances and narrow habitat requirements.
The first hypothesis, called favorable-environment hypothesis, states that naturally species live in benign environments, e.g. less-extreme climates or in largeer or less-fragmented habitats. In the (Neo)tropics the climate may be more stable indeed, although some situations come to mind where naturally rare species live under extreme conditions, e.g. high in the páramos in the eastern Cordillera of Colombia. But perhaps it are these exceptions which confirm the rule...!?

Stenostylus nigrolimbatus (Pfeiffer), at 4300 m in Páramo de Almorzadero, Colombia. Photo courtesy of Antoine M. Cleef.

The second, intrinsic-trait, hypothesis is that naturally rare species tend to have life history traits that confer extinction resistance. When I think of snails, it doesn’t instantly ring a bell with me...
The third, rapid-speciation, hypothesis supposes that naturally rare species do go extinct more frequently over evolutionary time than non rare species. This would imply that they should be younger on average and more likely to belong to rapidly speciating lineages.
Especially the first and third hypothesis seem to me to be testable with snails.

Tags: literature

In a new journal, I found a paper (Harrison et al., 2008) on rare species and favourable environments. The paper deals with plants but highlights some interesting topics which might be applicable for snails too.
Understanding the association of rare species with their habitats (flora, fauna and climatic requirements) is important for regions with a high biodiversity and endemism, especially if these are vulnerable for climatic change and other, more direct, human impacts. Rare species are then defined as range-restricted, habitat specialists which have a low local abundance. Although these three aspects may vary independently, depending on the biota, available studies have found that often a high proportion of species in rare in all aspects. However, data is scarce and either regional (McCoy & Mushinsky, 1992) or for mammals only (Yu & Dobson, 2000).

Two aspects need more consideration when it comes to land snails, viz. habitats specialism and local abundance. The former may be expressed both in biotic and abiotic terms, e.g. the availability of associated plant species and climatic variables. According to Pfenninger (2004) the most relevant variables for the climatic tolerance of land snails are: minimum avaerage monthly precipitation, maximum annual temperature range between hottest and coldest month; minimum number of months with average daily temperatures above 10 degrees, maximum monthly average daily temperature and minimum monthly average daily temperature. His data were derived from a study on Western Palaearctic land molluscs and I currently don’t know of any comparable data for tropical snails. Local abundancy may be influenced primarily by substrate, viz. the presence or absence of calcareous soils. A quote from my upcoming paper on the Guayana Highlands as illustration:
It has been observed elsewhere in the tropics that in lowlands often snails occur in low abundance, due to nutrient(Calcium)-poor and acidic soils. The malacofauna that can survive under such conditions consists often of (larger) snails living on (tree-like) vegetation off the ground (J.J. Vermeulen, personal communication). In uplands the weathering of rocks may leach more minerals and thus explain the relatively higher—but in absolute terms still low—numbers of specimens found.

Is the frequency of rarity also (relatively) high in landsnails as was found in other studies, especially in tropical regions (Yu & Dobson, 2000)? If so, it would be interesting to know their distribution characteristics in the (Neo)tropics. The results could be important for conservation policies and management, especially in biodiversity hotspots, although there is a vast literature base and the biodiversity field has received much attention.

References:
Harrison, S., Viers, J.H., Thorne, J.H. & Grace, J.B., 2008. Favorable environments and the persistance of naturally rare species. -- Conservation Letters 1: 65-74.
McCoy, E.D. & Mushinsky, H.R., 1992. Rarity of organisms in the sand pine shrub habitat of Florida. -- Conservation Biology 6: 537-548.
Pfenninger, M., 2004. Comparative analysis of range sizes in Helicidae s.l. (Pulmonata, Gastropoda). -- Evolutionary Ecology Research 6: 359-376.
Yu, J. & Dobson, F.S., 2000. Seven forms of rarity in mammals. -- Journal of Biogeography 27: 131-139.

Tags: literature, conservation

Taxonomy is an old science, but seemingly still expanding: recently a new journal was announced, ZooKeys.


ZooKeys is an open-access journal, which so far didn’t exist entirely focussed on systematic zoology. They do charge a little page charge (smaller than competitors), which however may be discounted or waived.
Discounts and waivers will be offered to private and retired zoologists, as well as to scientists from low- and middle-level income developing countries (according to the World Bank classification).
Papers containing identification keys will be published with priority (the names says it all). So far I see only papers on insects, which leaves ample room for malacologists. But unlike some other journals ZooKeys is not yet indexed due to its infancy (3 issues have been published till now), so if you need an impact factor to accelerate your career you have to look somewhere else until the journal have reached maturity. Private and retired zoologists have thus a double bonus here :-)

Tags: literature

Cuba is known for its diversity in land snails, but until now no comprehensive book was available. This seems to have changed recently, since I received notice of the new publication by Alejandro G. Guillén, Cuba - the landshells paradise, 305 pp., 25 colour plates. It is published by Conchbooks.
Just a few pictures of Liguus from the brochure that was sent out today.




More on it later, when I’ve seen the actual book.

Tags: literature, Liguus

Those bromeliads put me on track of this great website: Mongabay. Devoted to rain-forests throughout the world, I found it highly informative and worthwhile. Besides some general sections, e.g. on indigenous people and biodiversity, there is a wealth of information on deforestation and data per country. Data sources are e.g. FAO, UNEP and WorldWatch Institute, but there is a detailed list of references for each section. And, of course, also a section on the canopy...including bromeliads.



It provides also a wealth of pictures, both from undisturbed forests and from deforestation. Biodiversity pictures are from plants, birds and insects. Snails are missing, but I have to admit, you must be keen on them to spot them and the conditions have to be right :-)



And finally the links section is an endless resource for other rainforest topics, blogs and news.
Knowing that this is one-person endeavour, Mr. Butler... chapeau!

Tags: conservation, ecology, literature

Bromeliads belong to a diverse group of flowering plants, which in part are epiphytic. There are around 3000 species known from the Neotropics. Growth forms vary with environmental conditions, but typically there are a collection of wide, linear, straplike leaves with inflated bases that overlap to construct a tight rosette. These rosettes often form watertight tanks that can hold rainwater for many days.



Many of these tank bromeliads live in montane (cloud) forest where they can usually be found in the canopy. Out of reach of the "normal" biologist, as you need to climb high if you want to make observations. Yet they are known habitats for insects, frogs, epigeic earthworms, ostracods and also are a foraging site for birds.



Snails have also been associated with bromeliads. Basically there are two groups: one on Tillandsia sp. and one on (probably) other tank bromeliad genera. The first groups concerns Bostryx species from Peru, e.g. B. bromeliarum (Pilsbry, 1930) and the B. spiculatus-group.



The second group comprises Simpulopsis species, and although most have been described without mentioning of their habitat, given their locations and the association with bromeliads of some of them, I have a strong suspicion that several species might be associated with tank bromeliads. We know at least that S. simulus (Morelet, 1851) and S. magnus Thompson, 1957 have been found in bromeliads. The same might be true for S. corrugatus Guppy, 1866 from Trinidad and several species reported from the east coast of Brazil (Atlantic Forest, or what is left of it).

Enough of this rambling on bromeliads and snails... What about the beetles?
Merely by chance I stumbled upon the recent paper by Balke et al.* on the association between aquatic beetles and tank bromeliads. They studied a group of beetles that occurs in small water bodies in tropical forests, but a small subset of them is specialized to the water reservoirs of tank bromeliads. Extensive phylogenetic work revealed that the origin of one of the lineages was estimated to be comparable to that of the tank bromeliads. The other two lineages that are associated with these plants are thought to be more recent expansions into the tank water habitat.



The evolution of these canopy communities is far from being understood and leaves several areas open for further research. Snails being but one of them.

Reference:
Balke, M., Gómez-Zurita, J., Ribera, I., Vilora, A., Zillikens, A., Steiner, J., García, M, Hendrich, L. & Vogler, A.P. (2008). Ancient associations of aquatic beeles and tank bromeliads in the Neotropical forest canopy. Proceedings of the National Academy of Sciences of the United States of America, 105, 6356-6361.

Tags: literature, Simpulopsis, Bostryx, ecology, Peru

The third in a suite on habitat destruction and its possible impact on snails. This time Mexico, where I remember to have travelled through vast forests in 1974. If I see the map below, I can only be horrified on what must have been gone.



Almost 50% of the native montane forests existing in 1975 was cleared 25 years later (Cayela et al. 2006). Although deforestation rates are said to be relatively low compared to those in South-East Asia (Mayaux et al. 2005), it is apparent from remote sensing data that large areas of deforestation are to be found in the foothills of the Andes. Agricultural expansion and new settlements are the main drivers.



While some have questioned the deforestation rates, also non-forest habitats are converted at a large extent. Thus, the 1222 species of terrestrial snails on the Red List (Lydeard et al. 2004) seem to me a gross underestimation.

The effects on the snail fauna in the Pacific is well documented (partly invasive species demanded their toll too), but the effect of large-scale deforestation in Latin America seem to have passed unnoticed. To what extent did it affect the land snail fauna? Are some groups more affected than others? Are there examples of 'niche flexibility' that favours survivors?

References:
Cayuela, L., Rey Benayas, J.M. & Echeverria, C. (2006). Clearance and fragmentation of tropical montane forests in the Highlands of Chiapas, Mexico (1975-2000). Forest Ecology and Management, 226, 208-218.
Lydeard, C. et al. (2004). The global decline of nonmarine mollusks. BioScience, 54, 321-330.
Mayaux, P. et al. (2005). Tropical forest cover change in the 1990s and options for future monitoring. Philosophical Transactions of the Royal Society London B, 360, 373-384.

Tags: Mexico, conservation, literature

It is pure speculation, but just as with Ecuador, I suspect a correlation between deforestation and the "missing re-occurrences" of many once described snail species in Colombia. One would expect that human impact on the land cover change must have its toll also in the malacofauna. Again, I don't know for sure, but it could be an area for further research.
Here are some data that I found in Etter et al (2006):



With modelling the likelihood of deforestation was predicted and compared with observations using remote sensing techniques. The above map give the results in combination with areas of high biodiversity. But what is also clear from the figure, is the large area of cleared forests (gray). Of course it will depend to some extent in what the new land use is, but arboreal species will prove to be vulnerable (to say the least). It is exactly what I observe in my species list. But no hard data. Yet...

Reference:
Etter, A., McAlpine, C., Wilson, K., Phinn, S. & Possingham, H. (2006). Regional patterns of agricultural land use and deforestation in Colombia. Agriculture, Ecosystems and Environment, 114, 369-386.

Tags: Colombia, conservation, literature

In the last issue of Systematic Biology there is a paper of Dos Santos et al.*, describing a new methodology to find patterns of sympatry with the use of a network model analysis. Patterns of sympatry are important in biogeography, to find areas of endemism. The paper proposes some new definitions (sympatry, intermediate species) and offers a new tool, Network Analysis Method (NAM), as an add-on to the statistical package R (freeware, open source).

The NAM is a method that follows a strict algorithm:

The paper gives three examples applied to empirical data: land snails from northwestern Argentina, Neotropical fishes and South African weevils. When applied to land snails, Epiphragmophora, I find the results convincing, despite the fact that occurrence records from single localities (qu, es, vi, pl in figure a below) are not taken into account. These 'singletons' are often a signal of range-stricted endemic species.

The new methodology may be compared to other methods, of which the parsimony analysis of endemicity (PAE) is probably most used.

In total I think that this is a promising methodology and I look forward to see new applications of it to Neotropical land snails.


Reference
Dos Santos, D. A., H.R. Fernández, M.G. Cuezzo & E. Domínguez. (2008). Sympatry inference and network analysis in biogeography. Systematic Biology, 57, 432-448.

Tags: literature, methodology

This week Fred Thompson published his Checklist and bibliography of the land and freshwater snails of Mexico and Central America. It is a very impressive work, bringing together all information on taxa from this vast and interesting area. All together it list 1491 species, 278 subspecies, all native, and 20 introduced species. Of these, terrestrial species number 1139 (130 operculates, 1109 pulmonates).
The importance of this work, even without any revisionary work or photographs, is large. And it will be an invaluable source of reference and future research, both in the short and long term.
By making the publication free online at the website of the Florida Museum of Natural History, it will undoubtedly stimulate the interest of malacologists in Mexico and Central America.
Chapeau Fred!

Tags: literature, Mexico, Central America

Recently I came across the PhD-thesis of Kathleen Beese* on the evolution of reproductive traits in gastropods. In one of her papers she analyses the complexity of the carrefour, based on a comparative study in 47 snail species, two of which are Orthalicids. The data used for this part of her study were sequence data. These were taken from literature (Wade et al., 2006), but I was surprised that the source of these data seemed completely inadequately quoted:

It not only seemed a simple misidentification, but also a faunal confusion. Bulimulus semicinctus [= B. lherminieri] occurs on Guadeloupe, West Indies; B. sporadicus is a species from southern Brazil, Uruguay, Paraguay, Bolivia and northern Argentina. The same with Drymaeus: D. papyraceus lives in eastern Brazil, D. discrepans in Central America. For a taxonomical thesis this would be a severe lapsus, but luckily the thesis is about morphology...
Now on this subject it is quite interesting as she distinguishes four types of carrefour qua complexity and links that to shell size, longevity, reproductive strategy and habitat preference. The Orthalicidae are among the groups that have the most complex type of carrefour, but the evolutionary analyses suggest that this evolved independently. Thus convergence.
Upon searching for the source of confusion, it appeared that the data on the anatomy of the carrefour (derived from Van Mol, 1971) have been mingled with data on sequences (as used by Wade et al., 2006). That is a nice combination of morphology and genetics, leaving the taxonomist sandwiched in between and puzzled.

References:
Beese, K. (2007). The evolution of male and female reproductive traits in simultaneously hermaphroditic terrestrial gastropods. Universität Basel, Basel.
Van Mol, J.J. (1971) Notes anatomiques sur les Bulimulidae (Mollusques, Gastropodes, Pulmones). Annales Soc. Royale Zoologique Belgique, 101, 183-226.
Wade, C. M., P.B. Mordan & F. Naggs. (2006). Evolutionary relationships among the Pulmonate land snails and slugs (Pulmonata, Stylommatophora). Biol. J. Linnean Soc, 87, 593-610.

Tags: literature

Biomapper is another software program for species distribution modeling. Personally I have run it only once (on my old Windows machine, but I prefer cross-platform solutions). Their discussion forum, however, is very informative, issuing regularly an update on recent literature dealing with ENFA or Biomapper. I wished some other groups also delivered this service... Below are the 6 most recent publications, all available as PDFs on the Biomapper site.

References:
* Calenge, C., Darmon, G., Basille, M., Loison, A. & Jullien, J.M. (2008) The factorial decomposition of the Mahalanobis distances in habitat selection studies. Ecology, 89(2), 555-566.
* Strubbe, D. & Matthysen, E. (2008) Predicting the potential distribution of invasive ring-necked parakeets Psittacula krameri in northern Belgium using an ecological niche modelling approach. Biol Invasions, on-line.
* Allouche, O., Steinitz, O., Rotem, D., Rosenfeld, A. & Kadmon, R. (2008) Incorporating distance constraints into species distribution models. Journal of Applied Ecology, 45(2), 599-609.
* Long, P.R., Zefania, S., Ffrench-Constant, R.H. & Szekely, T. (2008) Estimating the population size of an endangered shorebird, the Madagascar plover, using a habitat suitability model. Animal Conservation, 11(2), 118-127.
* Praca, E. & Gannier, A. (2008) Ecological niches of three teuthophageous odontocetes in the northwestern Mediterranean Sea. Ocean Science, 4(1), 49-59.
* Skov, H., Humphreys, E., Garthe, S., Geitner, K., Gremillet, D., Hamer, K.C., Hennicke, J., Parner, H. & Wanless, S. (2008) Application
of habitat suitability modelling to tracking data of marine animals as a means of analyzing their feeding habitats. Ecological Modelling, 212(3-4), 504-512.

Tags: literature, software

Undoubtedly a great help and I wished there were even more of them, but at the same time it has to be recognized that the content cannot always be trusted. It is the same old story: GIGO, garbage in, garbage out.

The most logical start would be GBIF. I have seen some quite good results when I consulted their Australian data on Bulimulidae, but when I searched for data on South American species the results were poor. So far, databases from individual museums are for me a better choice. Here is a list of the databases that I have consulted quite frequently during my current research.

EU. There are several databases, of which the Senckenberg, Berlin and Brussels museums are the most promising. Yet they all ask me to come over to study their collection and and to look for what I need. To travel or to loan, that's an other interesting topic...

USA. For me the most informative database is those of the Florida Museum (chapeau Fred and John!). Also very useful are the Field Museum and Philadelphia museum databases. Furthermore I have consulted the Smithsonian and Harvard museum databases. It is always a good start, but don't forget to contact the curator to get the full details

Brazil. The list of institutions that participate in the speciesLink project is impressive. However, there are currently only three malacological collections accessible (although I regularly encountered server errors): INPA-Mollusca (Manáus, Amazonas), UFES-Malacologia (Vitória, Espírito Santo) and ZUEC-GAS (Unversidade de UNICAMP, Campinas, São Paulo). After several trials I ended up with a partial list of results only. UFES was the only database to respond, which may be due to the distributed set up of the project. Still a start that can only improve over time.

Finally, I like to mention here a recent paper by Neale et al.* on some principles for usability. They highlight the need for end-user involvement in the development of online databases. I cannot stress the importance of this point enough!

Reference:
Neale, S. H., M.R. Pullan & M.F. Watson. (2007). Online biodiversity resources - principles for usability. Biodiversity Informatics, 4, 27-36.

Tags: bioinformatics, literature, museums

The title refers to an interesting recently commentary in the Journal of Biogeography*, where Michael Patten argues that speciation and specialization are the same phenomenon. I'm not going to repeat his arguments here, but some of his conclusions are mind-provocative.
The first is that a simple geographic barrier becomes inadequate to 'explain' divergence between populations. If subtle differences in climate lead to subtle difference in vegetation, which in turn leads to different behaviour. In most cases one have to think in geological timescales to imagine how these subtle differences lead to larger differences and effective speciation comes into play.
I always wonder how these general theories work out in malacology. Just an example that puzzles me, possibly speciation still at work.

Imagine you see the shells above. The only thing you know is that they all occur in the same region, more or less at the same altitude, but at two sides of a river. I have plotted the (approximate) localities (taken from labels and collected some 40 years ago) on this map:

Now the question is, what would you call it? One species? Four subspecies? Two subspecies? I'm inclined to say the latter, but this case clearly needs further investigation. It would be nice to study these populations genetically to see to what extent the morphological differences can be explained. The only problem is: these animals occur high up in the Andes, Río Rimac valley, 3300-3400m. Any volunteers for collecting?

Reference:
Patten, M. A. (2008). The intersection of specialization and speciation. J. Biogeogr, 35, 193-194.

Tags: speciation, Peru, Bostryx, literature

Much has been said already (and undoubtedly more will still be said) about the biogeography of the southern hemisphere. In a recent review, Paul Upchurch summarizes hypotheses about Gondwanan biogeography into four models [here a broad summary of a summary]:

a) A 'Samafrica model' where Gondwana was divided into South America and Africa on one hand and East Gondwana (Antarctica, India, Madagascar and Australia) on the other hand.
b) The 'Africa-first' model' assumes that Africa was separated in an early stage, while South America remained longer in contact with East Gondwana until they finally broke up.
c) The 'Pan-Gondwana model' suggesting that all areas remained connected and then separated almost simultaneously.
d) 'Trans-oceanic dispersal model' following investigations of divergence times for species living on different continents and comparing them with the ages of the oceanic barriers between them.

From a theoretical point of view two phenomena have largely been ignored in biogeographical analyses: distributional noise (created by sampling errors) and the effect of geodispersal producing multiple signals. Geodispersal is the expansion of the ranges of species in response to the removal of a geographical barrier (e.g. erosion of a mountain range). Recent insights are that vicariance and geodispersal are alternating by the creation (upheaval) and destruction (erosion) of geographical barriers. The result is a network of interactions between biotas, rather than a simple branching pattern produced by vicariance alone (also called 'reticulate model'). This pattern may be group specific, depending on their specific reactions to physical events and their ecological requirements. Thus multiple biogeographical patterns may occur and recently some patterns-spotting techniques have been developed to untangle reticulate histories.

Upchurch continues by giving some implications for palaeobiogeography and molecular biology. E.g. he criticizes the lack of uncertainty in calibration of ages of fossil taxa (divergence times should be given with a confidence interval) and the calibration of molecular clocks using the age of geographical barriers. Different groups produce different patterns because of genuine biological processes (e.g. their difference in dispersal mechanism), but it is likely that partly the debate is flawed by ambiguities caused by distributional noise and multiple signals. His conclusion is that Gondwanan biogeographical history is proving to be even more complex than previously realized. He strongly advocates the use of pattern-spotting methods to distinguish between genuine patterns and artefacts produced by sampling and other errors.

I think that Upchurch has a point in arguing that the biogeographical history of Gondwana is even more complex than realized so far. Ranges in time expressing uncertainty and different scenarios could be more explicit, especially when dealing with older geological times. Possibly too often nuances are lost (or condensed) in the editing process, given the maximum number of pages a paper is allowed in many journals. And I wonder if the dispersal mechanism of the particular group under consideration is always given sufficient weight. It may be a dilemma to balance between generalizations and the specifics of the group.
There are several points in this useful review that are worthwhile to consider when we look into the relationships of the Orthalicidae (sensu lato). I will undoubtedly come back to this issue later.

Reference:
Upchurch, P. (2008). Gondwanan break-up: legacies of a lost world? Trends in Ecology & Evolution, 23, 229-236.

Tags: literature, Gondwana

Taxonomy is a field where many papers and books remain of value, even many decades after their publication. Systematic biology depends to a large extend on historic literature, and the 'half life' or 'decay time' is substantially longer than in other fields of science.
At the same time it is obvious that many old books and journals are difficult to consult, as they are often confined to the larger libraries in de developed world. The Biodiversity Heritage Library is likely to change this drastically. It aims to make major literature available through open access.
Currently one of the interesting titles is the Manual of Conchology, *the* landmark publication for me in malacology. Vols. 1-26 are now available, although all text is in uncorrected OCR. And text only! Still this is a major breakthrough in making taxonomy literature available 'for the masses'.

Tags: literature

For one of my papers in preparation I was looking to solve the publication dates of Hidalgo's contribution to the results of the 'Viajes al Pacifico'. This well-known Spanish expedition into the Neotropics is now extensively documented and accessible through the internet. It's context is described by López-Ocón and Badia (2003):

This article describes from a constructivist perspective a Natural History expedition put together by the Spanish government and navy to visit territories in the Pacific in the 1860s. Right from the start the expedition ran into problems and barely made it back. However, it managed to compile an admiringly large assortment of specimens: extensive collections of shells, mammals, skulls, and photographs. The expedition was rooted in colonialism. Patrons and organizers of the expedition sought to recreate in Spain discourses and practices then dominant in France, particularly the colonial agenda of the Société Impériale Zoologique d'Acclimatation. The collection assembled by the Comisión Científica del Pacífico had a life of its own. Years after the expedition folded, the collection kept on circulating and inspiring local and foreign scientists to identify new species and draw lessons from anthropology to history. The study of this collection was always discontinuous, a fact that proves the guadianización of science in Spain. The collection has been revived after a number of serendipitous discoveries in various Spanish archives, particularly caches of old photographs. Presently, the website www.pacifico.csic.es is expected to contribute to the circulation of the inscriptions generated by this scientific expedition.

On the website I found the plates, of which I copy two here. Plates 1 and 6 seem to be missing.


References:
Hidalgo, G. (1869) [1872]. Moluscos del Viaje al Pacifico. Parte primera: Univalvos terrestres. Madrid: Miguel Ginesta.
López-Ocón, L. & S. Badía (2003). Overcoming obstacles: The triple mobilization of the Comisión Científica del Pacífico. Science in Context, 16, 505-534.

Tags: literature, biohistory

This week arrived the long-expected paper by Dai Herbert on Prestonella. Or rather I should say, the first paper, as a second one dealing with the phylogeny is still on its way.
Since the first reference to Prestonella as a member of the Bulimulidae (Herbert & Mitchell, 2004), I have been very curious to know more about its relationships to other subfamilies or genera. Still, we have to hold our breath as this paper deals primarily with the taxonomy and presents an in-depth revision of the three taxa. The only 'sneak preview' is a statement that "Prestonella [is] in a well supported, monophyletic, orthalicoid clade structured in the following manner: Amphibulimidae + (Bulimulinae + (Prestonella + (Bothriembryon + Placostylus)))".

Herbert was able to recollect two of the species near their type localities and gives useful data on their ecology as well. The genus is endemic to South Africa and its distribution is very relictual.

It's a pity that the figures in the paper are not in colour, as these snails are very pretty (for land snails :-). This photo, by courtesy of Dai, shows Prestonella bowkeri (Sowerby, 1890).



References:
Herbert, D. G. & Mitchell, A. (2004). Prestonella, the missing African element in the Gondwanan family Bulimulidae (Mollusca, Pulmonata). Paper presented at the IV Southern Connections Conference, Cape Town, 19-23.1.2004.
Herbert, D. G. (2007). Revision of the genus Prestonella (Mollusca: Gastropoda: Orthalicoidea: Bulimulidae s.l.), a distinctive component of the African land snail fauna. African Invertebrates, 48, 1-19.

Tags: literature, South Africa, Prestonella

During scanning of literature I found a paper* dealing with entomology but containing nevertheless information that could be handy in other fields as well. One of the references was to site that I found already some years ago, but lost afterwards. It contains a useful survey of programs for interactive identification and information retrieval. As usual there is a distinction between free and commercial respectively between Windows and other platforms (notably Java). It will be clear why my preference will be.
The Delta program is now called Intkey, but essentially is the same and might be useful for building keys or to allow identification of species through a webinterface. Useful but cumbersome to compile, unless you make it a hebit right from the start.

Reference:
Johnson, N. F. (2007). Biodiversity informatics. Annual Review Entomology, 52, 421-438.

Tags: literature

In the last number of Systematic Biology a number of papers are devoted to species delimitation. They are resulting from a symposium that was held in 2006 in Stony Brooks by the Society of Systematic Biologists and chaired by John Wiens.
Two papers are especially noteworthy, dealing with lizards (Rissler & Apodaca, 2007) and geckos (Raxworthy et al., 2007), both exploring the use of ecological niche modelling (ENM).

While delimitation of species and species concepts are theoretically debated for some time (e.g., de Queiros, 2007; Sites & Marshall, 2003, 2004; Wiens, 2004, 2007), it is interesting to see how ENM is used to shed light from a more practical point of view. In the paper of Rissler & Apocada the distribution of different 'lineages' of a lizard is analyzed, using phylogenetic methods and bioclimate data. It includes a figure with spatial representation of the several lineages, using GeoPhyloBuilder (unfortunately only working with ArcGIS; why not cross-platform and for general GIS software??). With ENM the contact zones between the different lineages are visualized and they argue that genetic and ecological data prove to be more convincing than morphological differences between lineages. They suggest that future phylogeographic and biogeographic analyses will be more explicitly concerned with spatial and geographic components of genetic variation and speciation than is currently evident. This is certainly a challenge for Neotropical malacology.

I was even more charmed by the paper of Raxworthy et al., who deal with geckos from Madagascar. They use ENM (Maxent; review here) to identify erroneous localities (which could also be the consequence of misidentifications in collections or literature) and develop a method for comparing niche models based on split and lumped taxonomic groupings. In this study they use this method for species delimitation and unveil a cryptic species. Morphological or molecular data were used to guide for partitioning localities between suspected species. Subsequently, using both the lumped and split taxonomic groupings, niche models were compared for predictive performance. They conclude that ENM is especially useful for species delimitation in groups that show high levels of local endemism or include cryptic species which show little morphological and molecular divergence.
Their phylogenetic analyses were done using ethanol 70% and formalin-fixed specimens from museum collections. I wonder if this method would work also in snails...


References:
Raxworthy, C. J., C.M. Ingram, N. Rabibisoa & R.G. Pearson. (2007). Applications of ecological niche modeling for species delimitation: a review and empirical evalutation using day geckos (Phelsuma) from Madagascar. Systematic Biology, 56, 907-923.
Rissler, L. J. & J. J. Apodaca (2007). Adding more ecology into species delimitation: ecological niche models and phylogeography help define cryptic species in the Black Salamander (Aneides flavipunctatus). Systematic Biology, 56, 924-942.

Further references:
de Queiroz, K. (2007). Species concepts and species delimitation. Systematic Biology, 56, 879-886.
Sites, J. W. & J. C. Marshall (2003). Delimiting species: a Renaissance issue in systematic biology. Trends in Ecology and Evolution, 18, 462-470.
Sites, J. W. & J. C. Marshall (2004). Operational criteria for delimiting species. Annual Review Ecology Evolution Systematics, 35, 199-227.
Wiens, J. J. (2004). Speciation and ecology revisited: phylogenetic niche conservatism and the origin of species. Evolution, 58, 193-197.
Wiens, J.J. (2007). Species delimitation: new approaches for discovering diversity. Systematic Biology, 56, 875-878.

Tags: literature

A bit sluggish, I must admit, but the yearly newsletter of the IUCN/Species Survival Commission - Mollusc Specialist Group (wow, could it be lengthier?) is out since a few weeks.

Number 16 has some interesting stuff:
- Land snail diversity and centres of botanical endemism: Dai Herbert and Adnan Moussalli make the interesting observation that areas recognized by botanists as rich in endemics, also harbour a rich diversity of land snails. They write: "From a biogeographical perspective it is easy to appreciate that the historical environmental processes that have created these local foci of plant endemism could likewise underpin similar foci of land snail endemism". I completely agree, but this line of thought also reminds me on the reviled works of Croizat*.
- Tracking land snail extinctions from space: Menno Schilthuizen and Reuben Clements argue on the basis of observations of snails from Malaysia, that it would be worthwhile to use remote sensing to monitor extinction processes by biotope destruction. While their paper focusses on limestone outcrops and karst snails, I immediately had to think about what Eugenia Salas told me about Argentina. During her fieldwork she discovered that several localities where Spixia had been reported from literature, had been destroyed due to the conversion to agricultural use. Threats to land snails are manifold as part of the biodiversity crisis that we face.
- Non-marine mollusc diversity in Paraná State, southern Brazil: Ignacio Agudo discusses the number of land and freshwater snails and bivalves. He mentions only families, treating Bulimulidae, Amphibulimidae and Odontostomidae as distinct. In Paraná, with 9000 km2 a relatively small state, 17, 1 and 5 species are recognized respectively. Simone** lists for the Bulimulidae 176, Amphibulimidae 20 and Odontostomidae 88 species for Brazil.
- From malacological data to analysis: Péter Sólymos has written an extension for the statiscal R-package, called "mefa" (metafaunistics). It could be a nice supplement to StatCrunch, and as it is freeware it is defenitely worth a try. To be continued in a later post.

References
* L. Croizat (1958) Panbiogeography, I, IIa, IIb. Caracas: published by author; L. Croizat (1962 [1964]) Space, time, form: the biological synthesis. Caracas: published by author.
** Simone, L.R.L. (2006) Land and freshwater molluscs of Brazil. Sao Paulo: EGB, Fapesp.

Tags: literature