dec 2006
Food for thought
31-12-2006 17:09
Earlier this week I was
reading some reprints I recently came across. One of
the papers was about combining phylogenetics and
bioclimatic modeling*). This is a new line of
research and very interesting given the results of my
experiments with DIVA-GIS**). Although the main part
of the paper was on plants, it opens up a wide scope
of literature.
One of the interesting topics touched upon in the introduction is the suggestion that "bioclimatic enveloppes are statistically more similar among sister species and that they are conserved across evolutionary time". That is some food for thought...
It is supported by two examples from birds resp. plants, where one established first the relationships and then analysed the bioclimatic enveloppes. How were the sister relationships established? Is it only relevant to sister groups at the species level? What bioclimatic variables were included in the enveloppes? Have palaeoclimates been included in the analysis to verify that the relationship between phylogeny and bioclimatic enveloppes is constant? Has the phylogeny been calibrated by the inclusion of fossil data?
Sometimes a few words initiate more questions in a few minutes than one can answer in the time available.
*) Yesson, C. & A. Culham (2006). Syst. Biol. 55: 785-802.
**) www.diva-gis.org (unfortunately only available for Windows platforms)
One of the interesting topics touched upon in the introduction is the suggestion that "bioclimatic enveloppes are statistically more similar among sister species and that they are conserved across evolutionary time". That is some food for thought...
It is supported by two examples from birds resp. plants, where one established first the relationships and then analysed the bioclimatic enveloppes. How were the sister relationships established? Is it only relevant to sister groups at the species level? What bioclimatic variables were included in the enveloppes? Have palaeoclimates been included in the analysis to verify that the relationship between phylogeny and bioclimatic enveloppes is constant? Has the phylogeny been calibrated by the inclusion of fossil data?
Sometimes a few words initiate more questions in a few minutes than one can answer in the time available.
*) Yesson, C. & A. Culham (2006). Syst. Biol. 55: 785-802.
**) www.diva-gis.org (unfortunately only available for Windows platforms)
A mystery to be solved
27-12-2006 12:05
The genus
Simpulopsis
Beck 1837 is disjunctly
distributed in the Neotropics, ranging from southern
Brazil to southern Mexico and Guatemala in the north.
It is also reported from northern Argentine,
Paraguay, Peru, Ecuador, Colombia, Venezuela,
Trinidad and St. Vincent. The species seem to be
restricted to tropical and subtropical rain and cloud
forests, where they generally live in low density.
There is, however, one more locality reported:
Simpulopsis
dominicensis from Hispaniola. A hardly known
species which is doubtfully referred to the
Bulimulidae.
Recently Jozef Grego and Jozef Steffek made a trip to that island, hunting for a Clausiliid, Nenisca franzi, reported from Haiti. They were kind enough to send me the Bulimulids they found during this trip. One specimen was the mysterious Simpulopsis ....
Recently Jozef Grego and Jozef Steffek made a trip to that island, hunting for a Clausiliid, Nenisca franzi, reported from Haiti. They were kind enough to send me the Bulimulids they found during this trip. One specimen was the mysterious Simpulopsis ....
"Bulimulidae" or the confusion of progress
26-12-2006 21:16
Taxonomy is an odd
science and too often considered as old-fashioned and
out-dated. Especially now with the molecular genetic
studies, I hear often complaints from fellow
researchers at Naturalis (Leiden) that they
unsuccesfully applied for funding of projects. The
"modern" genomics-related proposals won....
However, what people tend to forget is that you can't be sure of the organism you study untill you are able to identify it properly. And that is what taxonomists are for.
When I concluded my revision of the Bulimulidae in 1979 life was fairly simple. Although the data did not allow to pinpoint the relationships between the several groups in detail, I was convinced at that time that the Bulimulidae as a whole were a solid group. In my view it consisted of 5 subfamilies: Bulimulinae, Amphibuliminae, Odontostominae, Orthalicinae and Placostylinae. Now, more than 25 years later, progress has been achieved and things are quite different.
First of all there is a nomenclatural issue. Bulimulidae as a family name appears to be pre-occupied by the Orthalicidae. And as some subfamilies have been raised to family rank, the group is now referred to as Orthalicoidea.
Furthermore the "Bulimulids" now also have an African offspring. Dai Herbert (Natal Museum) told me last year that he concluded that the genus Prestonella belongs to this group, as he will show by DNA-studies (still to be published).
Although over the years some people have worked on the group, relationships are still rather unclear. My suspicion is that a re-evaluation of the relationships at generic level, on the basis of DNA research, will reveal some truely surprising results. Sort of confusion for people interested in "Bulimulidae".... the few who are.
However, what people tend to forget is that you can't be sure of the organism you study untill you are able to identify it properly. And that is what taxonomists are for.
When I concluded my revision of the Bulimulidae in 1979 life was fairly simple. Although the data did not allow to pinpoint the relationships between the several groups in detail, I was convinced at that time that the Bulimulidae as a whole were a solid group. In my view it consisted of 5 subfamilies: Bulimulinae, Amphibuliminae, Odontostominae, Orthalicinae and Placostylinae. Now, more than 25 years later, progress has been achieved and things are quite different.
First of all there is a nomenclatural issue. Bulimulidae as a family name appears to be pre-occupied by the Orthalicidae. And as some subfamilies have been raised to family rank, the group is now referred to as Orthalicoidea.
Furthermore the "Bulimulids" now also have an African offspring. Dai Herbert (Natal Museum) told me last year that he concluded that the genus Prestonella belongs to this group, as he will show by DNA-studies (still to be published).
Although over the years some people have worked on the group, relationships are still rather unclear. My suspicion is that a re-evaluation of the relationships at generic level, on the basis of DNA research, will reveal some truely surprising results. Sort of confusion for people interested in "Bulimulidae".... the few who are.
Introduction
24-12-2006 17:48
Always wondered how it
is to be a malacologist? Read my blog and you might
get an idea. However, I must explain upfront that I'm
only doing malacological work part-time. Keep that in
mind when reading.
The main work that I did on Neotropical snails was done during the 1970's. After receiving my Ph.D. in 1979 I switched career and worked for the government and as a private management consultant. For many years I was an officer of the Dutch Malacological Society (Nerderlandse Malacologische Vereniging) and tried to keep an eye on relevant literature as good as possible. But I always kept my interest in Neotropical snails, especially the family Bulimulidae.
The main work that I did on Neotropical snails was done during the 1970's. After receiving my Ph.D. in 1979 I switched career and worked for the government and as a private management consultant. For many years I was an officer of the Dutch Malacological Society (Nerderlandse Malacologische Vereniging) and tried to keep an eye on relevant literature as good as possible. But I always kept my interest in Neotropical snails, especially the family Bulimulidae.