At the moment I'm a free-time researcher and as a
consequence I have to make the most of my limited time.
Nevertheless, there are several topics that interest me
very much and keep me busy. Most of these are done in
co-operation with other biologists.
in the Guayana Highlands
This work is being done in co-operation with Valentí Rull
(Universidad de Barcelona) and Mónica Vera (Instituto de
Ciencias Naturales, Bogotá). The basis is a hypothesis
formulated by Rull and the model species are Plekocheilus
species from northern Peru
Interesting material has been collected recently by Jens
Hemmen and may clarify some issues on several genera, like
the relations between Neopetraeus, Llaucanianus and
Drymaeus. There is co-operation with Bernhard Hausdorf
of the phylogeny of the Orthalicoidea
Since 1979, when I published a revision of the group, no
comprehensive re-evaluation has been made. Modern
techniques, like DNA sequencing, greatly enhace our insight
in the phylogenetic relationships, which at that time could
only be hypothesized. Several interesting topics have
occurred, like the placement of Prestonella from South
Africa in the group, that justify to take a fresh view
using up-to-date methods.
For this I also co-operate with Bernhard Hausdorf.
Mollusca from northern South America
This is a co-operative project with Francisco Borrero
(Cincinatti Museum of Natural History) to make a catalogue
of non-marine Mollusca, starting with an initial list of
species from Colombia made by him, which we use as a
starting point for further improvement and expansion to
other countries in northern South America. The old name for
this area is ‘New Grenada’ (hence the tab name), comprising
Colombia, Ecuador, and parts of Venezuela and
of the Orthalicoidea
Types are the fundament of the classification building and
it is important to know where type material is being kept
and to have accurate data of these types. This project aims
to revise museum collections and to (re-)publish types of
Orthalicoidea, both from described and undescribed taxa.
This is a project in co-operation with Eike Neubert
(Senckenberg Natur-Museum) and others.
My current interests may be summarized by this figure: