nov 2009
Through the looking glass
30-11-2009 19:25
Today we had a one-day
symposium at Naturalis, „Through the looking glass”,
about asymmetry, handedness, and mirror images in
nature.
Richard Palmer (University of Alberta), who is a visiting professor at the moment, did the key-note lecture on „Learning, developmental plasticity and evolution”.
Evolution by natural selection requires three steps. New variants of organisms: must arise, must have an impact on fitness (survival or fecundity), and must (ultimately) be heritable. The first step - how new variants arise - remains controversial. Traditionally, new phenotypes are attributed to novel genotypes (mutants or recombinants). But developmental plasticity may be a more important source of new variants than generally recognized.
The absence of heritable variation for direction of asymmetry in species that show a random mixture of asymmetric forms (i.e., equal numbers of right- and left-handed forms), identifies a unique phenotype - "direction of asymmetry" - for which there is no genotype. A wide-ranging survey of asymmetry variation within and among species of animals and plants offers some of the strongest evidence to date for a 'phenotype-precedes-genotype' mode of evolution. In addition, the tendency of many animals to learn (e.g., handed behavior) may facilitate both the origin and the amplification of right-left morphological differences via developmental plasticity. Such an interplay between learning and developmental plasticity might greatly enhance the rate of morphological evolution.
There were also lectures by Menno Schilthuizen and Edi Gittenberger on malacological subjects.
Menno talked about „A negative spiral: sex and body shape in tropical tree snails”, in which he showcased the work being doing on Amphidromus. The Malaysian species with which he is working, shows dimorphism and he concluded that probably aspects of the reproduction can explain why dimorphism does occur in this taxon. The coiled spermatophore plays an important role.
Edi Gittenberger eloborated „A very unlikely event”, in which he showed that although e.g. sinistrality is not rare in Japanese land snails, this can be traced back to three evolutionary events. And, as such, these may be considered rare events in evolutionary timeframe.
Richard Palmer (University of Alberta), who is a visiting professor at the moment, did the key-note lecture on „Learning, developmental plasticity and evolution”.
Evolution by natural selection requires three steps. New variants of organisms: must arise, must have an impact on fitness (survival or fecundity), and must (ultimately) be heritable. The first step - how new variants arise - remains controversial. Traditionally, new phenotypes are attributed to novel genotypes (mutants or recombinants). But developmental plasticity may be a more important source of new variants than generally recognized.
The absence of heritable variation for direction of asymmetry in species that show a random mixture of asymmetric forms (i.e., equal numbers of right- and left-handed forms), identifies a unique phenotype - "direction of asymmetry" - for which there is no genotype. A wide-ranging survey of asymmetry variation within and among species of animals and plants offers some of the strongest evidence to date for a 'phenotype-precedes-genotype' mode of evolution. In addition, the tendency of many animals to learn (e.g., handed behavior) may facilitate both the origin and the amplification of right-left morphological differences via developmental plasticity. Such an interplay between learning and developmental plasticity might greatly enhance the rate of morphological evolution.
There were also lectures by Menno Schilthuizen and Edi Gittenberger on malacological subjects.
Menno talked about „A negative spiral: sex and body shape in tropical tree snails”, in which he showcased the work being doing on Amphidromus. The Malaysian species with which he is working, shows dimorphism and he concluded that probably aspects of the reproduction can explain why dimorphism does occur in this taxon. The coiled spermatophore plays an important role.
Edi Gittenberger eloborated „A very unlikely event”, in which he showed that although e.g. sinistrality is not rare in Japanese land snails, this can be traced back to three evolutionary events. And, as such, these may be considered rare events in evolutionary timeframe.
New blog
27-11-2009 17:11
Modest Correoso,
malacologist in Quito, has started his own
blog on Ecuadorian land snails. As he
is a Cuban by origin, he is posting from time to
time also on the Cuban malacofauna.
Welcome to the malacoblogosphere!
Welcome to the malacoblogosphere!
Naming and other things
26-11-2009 19:44
Earlier this week a
special number of Spirula appeared, in which three
interesting papers appeared. Some of them are mainly
of interest to the Dutch readership.
The first paper by Van Gemert & Van Leeuwen describes the jubilees of the Netherlands Malacological Society during the past 75 years and the way some of its members have been honoured.
In another paper, Van Gemert gives a survey of the members of the Board and of the editors of the NMV journals.
In the third paper, Kronenberg gives a list of all eponyms of NMV members or persons related to them. As he correctly says, the easy way of placing -i, -ae, -orum or -arum behind the person(s) name is too often followed. He concludes „Come on, dear malacologists, use your imagination”.
As far as applicable, I promise to better my life in this respect.
The first paper by Van Gemert & Van Leeuwen describes the jubilees of the Netherlands Malacological Society during the past 75 years and the way some of its members have been honoured.
In another paper, Van Gemert gives a survey of the members of the Board and of the editors of the NMV journals.
In the third paper, Kronenberg gives a list of all eponyms of NMV members or persons related to them. As he correctly says, the easy way of placing -i, -ae, -orum or -arum behind the person(s) name is too often followed. He concludes „Come on, dear malacologists, use your imagination”.
As far as applicable, I promise to better my life in this respect.
Orthalicid radulae (2): Discoleus
25-11-2009 09:34
In my series Lost and
found, today the hitherto unfigured radula of
Discoleus
ventanensis (Pilsbry, 1896). As the name says,
it originates from Argentina, Sierra de la Ventana.
From left to right, top to bottom: interaction, detail of central, central + laterals 1-5, detail of L2, L6-10, L10-18, L19-30 and L30-33.
All pictures, also in the rest of this series, have originally been made by Simon Ploeger.
From left to right, top to bottom: interaction, detail of central, central + laterals 1-5, detail of L2, L6-10, L10-18, L19-30 and L30-33.
All pictures, also in the rest of this series, have originally been made by Simon Ploeger.
Snails and snakes
24-11-2009 08:14
In the last newsletter
of Unitas Malacologica (available from their
new address), a brief report is presented
by Ignacio Agudo on snail-eating snakes in
southern Brazil. It is based on a survey in
literature, museum collections and additional
observations in the field.
There are five species mentioned as prey for these reptiles: several veronicellid slugs - Belocaulus angustipes (Heynemann, 1885), Phyllocaulis soleiformis (d’Orbigny, 1835) and Sarasinula linguaeformis (Semper, 1885) -, an orthalicid tree snail - Mesembrinus interpunctus (Martens, 1887) and the invasive Bradybaena similaris (Férussac, 1821).
One of the reported snail species is Dipsas indica Laurenti, 1768, the common name of which is Neotropical snail-eater. This is probably based on Sazima (1989), who reported it from southern Brazil. According to the reptile database, this species is only found in Brazil in Bahia and Goias. However, it is also known to occur in Brazil and Paraguay.
References:
Agudo-Padrón, I., 2009. Snail-eating snakes of southern Brazil region and their alimentary preferences. - Unitas Malacologica Newsletter 28: 11-12.
Sazima, I., 1989. Feeding behavior of the snail-eating snake, Dipsas indica. - Journal of Herpetology 23: 464-468.
There are five species mentioned as prey for these reptiles: several veronicellid slugs - Belocaulus angustipes (Heynemann, 1885), Phyllocaulis soleiformis (d’Orbigny, 1835) and Sarasinula linguaeformis (Semper, 1885) -, an orthalicid tree snail - Mesembrinus interpunctus (Martens, 1887) and the invasive Bradybaena similaris (Férussac, 1821).
One of the reported snail species is Dipsas indica Laurenti, 1768, the common name of which is Neotropical snail-eater. This is probably based on Sazima (1989), who reported it from southern Brazil. According to the reptile database, this species is only found in Brazil in Bahia and Goias. However, it is also known to occur in Brazil and Paraguay.
References:
Agudo-Padrón, I., 2009. Snail-eating snakes of southern Brazil region and their alimentary preferences. - Unitas Malacologica Newsletter 28: 11-12.
Sazima, I., 1989. Feeding behavior of the snail-eating snake, Dipsas indica. - Journal of Herpetology 23: 464-468.
IUCN Red List
23-11-2009 14:26
This years update of
the Red List brought very little news for
invertebrates. When I searched for Neotropical
land molluscs, only 44 taxa showed up. The same as
last year...
Comparing the total number of molluscs in any of the IUCN categories with the data from last year, showed that there is an increase of five taxa in the Bivalvia and 89 in Gastropoda. Hence, a stunning 94 in total. The - new - factsheet on molluscs highlights a few selected species.
94 more species added to bring the total of assessed species up to 2306. Is this really stunning? Or just still a gross underestimation of the reality? And if so, why is so little progress obtained?
When I recently spoke to an insider, he said „the IUCN isn’t interested in invertebrates at all. And who cares about molluscs anyhow? The Red List is simply politics”.
That is a provocative conclusion. If true - and I have little reasons to doubt that my spokesperson was wrong - it is the death-blow to mollusc conservation efforts. Despite anything else that may be written in Tentacle, etc.etc.
Do we simply waste our time?
Comparing the total number of molluscs in any of the IUCN categories with the data from last year, showed that there is an increase of five taxa in the Bivalvia and 89 in Gastropoda. Hence, a stunning 94 in total. The - new - factsheet on molluscs highlights a few selected species.
94 more species added to bring the total of assessed species up to 2306. Is this really stunning? Or just still a gross underestimation of the reality? And if so, why is so little progress obtained?
When I recently spoke to an insider, he said „the IUCN isn’t interested in invertebrates at all. And who cares about molluscs anyhow? The Red List is simply politics”.
That is a provocative conclusion. If true - and I have little reasons to doubt that my spokesperson was wrong - it is the death-blow to mollusc conservation efforts. Despite anything else that may be written in Tentacle, etc.etc.
Do we simply waste our time?
NMV75
22-11-2009 21:30
Yesterday the Netherlands Malacological Society had its third meeting to celebrate its 75 years of existence. We have a tradition of making group photographs of these meetings. Here is the one taken yesterday in Naturalis, thanks to our Board member Jan Johan ter Poorten. He counted 108 members present.
Tools for cybertaxonomy
20-11-2009 16:27
Web-based taxonomy is
the way forward. Said it before, will say it more.
However, tools and the right choice of them is
utterly important to have good results and easy
interchange of compatible data.
EDIT has a special programme (WP5) that is devoted to cybertaxonomy and a special page that presents an overview of tools: Biodiversity Service & Application Tracker.
Software is divided both in type (applications, data) and in categories (from bibliography to taxonomy). In several categories there are recent additions, but an option is present to receive RSS feeds.
EDIT has a special programme (WP5) that is devoted to cybertaxonomy and a special page that presents an overview of tools: Biodiversity Service & Application Tracker.
Software is divided both in type (applications, data) and in categories (from bibliography to taxonomy). In several categories there are recent additions, but an option is present to receive RSS feeds.
Cuban limestone mogotes
19-11-2009 20:45
Cuban limestone hills
('mogotes') are famous for their rich malacofauna.
Recently a faunal list was published (Oliva-Olivera
& Real, 2009) for those of the Parque Nacional
Viñales, in the western province of Pinar del Río.
From the ca. 1300 species known from the island, the authors list 136 species for this national park occurring at 12 limestone hills. Twenty-one species are recorded for the first time from this region.
Although currently there is only a printed version available, the paper will also appear online at the site of the journal.
Reference:
Oliva-Olivera, W. & Real, R., 2009. Moluscos terrestres de las elevaciones cársticas de Viñales, Pinar del Río, Cuba. - Revista Biologia Tropical 57: 589-604.
From the ca. 1300 species known from the island, the authors list 136 species for this national park occurring at 12 limestone hills. Twenty-one species are recorded for the first time from this region.
Although currently there is only a printed version available, the paper will also appear online at the site of the journal.
Reference:
Oliva-Olivera, W. & Real, R., 2009. Moluscos terrestres de las elevaciones cársticas de Viñales, Pinar del Río, Cuba. - Revista Biologia Tropical 57: 589-604.
Orthalicid radulae (1): Bothriembryon
17-11-2009 19:27
This is strictly not
about Neotropical snails. But still about
orthalicids. And as the relationships between the
different group within the (super)family is one of my
research topics, I think it is still "on topic" for
this blog.
Sometimes you have data that you considered lost. I thought that all data used for my papers in the 70s and 80s had gone. This weekend I cleaned up a bit in my house and found a tray with several hundreds of SEM photographs of radulae, arranged according to different species.
Since only a small part has actually been published in the past (viz. my Zoologische Verhandelingen 164 [1978] and 168 [1979]), I think it is worthwile to grab from time to time some from this tray and put them up here.
It is astonishing to see that the quality of those old machines and analog photographs still is very comparable to those from modern equipment and which are digitally processed. The biggest difference is that modern machines are easily operated (I recently did myself, but that is something for a future post) and results can be swiftly processed.
The 'grab of the day' is Bothriembryon gunnii (Sowerby, 1845). This is an orthalicid occurring in Tasmania. The specimen shown here is from Coles Bay and kept in the Leiden museum (ZV 164: 209).
Upper figures: interaction between the teeth. Lower left: central; lower right: lateral 7-9.
Update: Now I realize that B. gunni is the name of the fossil species that occurs on Tasmania. The Recent species should be called B. tasmanicus (Pfeiffer, 1853).
Sometimes you have data that you considered lost. I thought that all data used for my papers in the 70s and 80s had gone. This weekend I cleaned up a bit in my house and found a tray with several hundreds of SEM photographs of radulae, arranged according to different species.
Since only a small part has actually been published in the past (viz. my Zoologische Verhandelingen 164 [1978] and 168 [1979]), I think it is worthwile to grab from time to time some from this tray and put them up here.
It is astonishing to see that the quality of those old machines and analog photographs still is very comparable to those from modern equipment and which are digitally processed. The biggest difference is that modern machines are easily operated (I recently did myself, but that is something for a future post) and results can be swiftly processed.
The 'grab of the day' is Bothriembryon gunnii (Sowerby, 1845). This is an orthalicid occurring in Tasmania. The specimen shown here is from Coles Bay and kept in the Leiden museum (ZV 164: 209).
Upper figures: interaction between the teeth. Lower left: central; lower right: lateral 7-9.
Update: Now I realize that B. gunni is the name of the fossil species that occurs on Tasmania. The Recent species should be called B. tasmanicus (Pfeiffer, 1853).
Another rare paper
13-11-2009 20:29
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.
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.
Photo of the day (76): Drymaeus
09-11-2009 18:46
Coloniconcha
06-11-2009 19:19
In an
earlier
post I
mentioned a remarkable species from
Hispaniola, Coloniconcha
prima Pilsbry, 1933. At that time I
didn't know exactly to which family it belonged.
Pilsbry originally had assumed that this species
was close to Polydontes,
which is placed in
the Pleurodontidae by Schileyko (2006).
Upon dissection, I can now confirm the classification by Pilsbry. Whether the family has to be called Pleurodontidae sensu Schileyko or Camaenidae sensu Cuezzo (2003) remains a matter of debate.
The paper giving all the details is close to completion.
References:
Cuezzo, M.G., 2003. Phylogenetic analysis of the Camaenidae (Mollusca: Stylommatophora) with special emphasis on the American taxa. - Zoological Journal of the Linnean Society 138: 449-476.
Schileyko, A.A., 2006. Treatise on Recent terrestrial pulmonate molluscs, 13. Helicidae, Pleurodontidae, Polygyridae, Ammonitellidae, Oreohelicidae, Thysanophoridae. - Ruthenica, Supplement 2: 1795-1906.
Upon dissection, I can now confirm the classification by Pilsbry. Whether the family has to be called Pleurodontidae sensu Schileyko or Camaenidae sensu Cuezzo (2003) remains a matter of debate.
The paper giving all the details is close to completion.
References:
Cuezzo, M.G., 2003. Phylogenetic analysis of the Camaenidae (Mollusca: Stylommatophora) with special emphasis on the American taxa. - Zoological Journal of the Linnean Society 138: 449-476.
Schileyko, A.A., 2006. Treatise on Recent terrestrial pulmonate molluscs, 13. Helicidae, Pleurodontidae, Polygyridae, Ammonitellidae, Oreohelicidae, Thysanophoridae. - Ruthenica, Supplement 2: 1795-1906.
Migration problems
05-11-2009 13:37
Due to technical problems my blog hasn't been updated for a few days. I apologize to those of you who regularly check the updates. Also I noticed that some posts have been mixed up. Working on the fixes, stay tuned...
New Taxa (19): Araucocharopa
02-11-2009 19:44
Recently, several new
taxa have been described from Chile.
Another one is now added by Sergio Miquel and
Francisco Cádiz Lorca. It is a small species
belonging to the Charopidae.
After a careful comparison with other genera from the same family occurring in Chile, Argentina and Brazil, the authors have come to the conclusion that this novelty belongs to a new genus. The name is derived from the area where the species is found.
The new species is named in honour of Carlos Gallardo. Type locality: Chile, XIV Región, Prov. Valdivia, Reserva Costera Valdiviana. Holotype: MNHNCL 6610.
Reference:
Miquel, S.E. & Cádiz Lorca, F.J., 2008. Araucocharopa gallardoi gen. et sp.n. de Charopidae (Mollusca: Gastropoda: Stylommatophora) del sur de Chile. - Revista Museo Argentino Ciencias Naturales, n.s. 10: 329-340.
After a careful comparison with other genera from the same family occurring in Chile, Argentina and Brazil, the authors have come to the conclusion that this novelty belongs to a new genus. The name is derived from the area where the species is found.
The new species is named in honour of Carlos Gallardo. Type locality: Chile, XIV Región, Prov. Valdivia, Reserva Costera Valdiviana. Holotype: MNHNCL 6610.
Reference:
Miquel, S.E. & Cádiz Lorca, F.J., 2008. Araucocharopa gallardoi gen. et sp.n. de Charopidae (Mollusca: Gastropoda: Stylommatophora) del sur de Chile. - Revista Museo Argentino Ciencias Naturales, n.s. 10: 329-340.