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Research topics

 

My research focuses on fossil and Recent gastropods. I am especially interested in the evolution, phylogeny, systematics, palaeo-diversity, and palaeoecology of the Gastropoda. My main focus is on Late Palaeozoic, Triassic, and Jurassic gastropods but I worked also on Recent gastropods (Nützel 1998). Gastropods are one of the most diverse metazoan groups. They have a good fossil record and therefore are very important for Palaeontology.

 

Permian / Triassic gastropod species data base

 

I have compiled a world-wide data base of probably more than 95% of all described Triassic gastropod species. It contains more than 2000 nominate gastropod species and information about their geographic distribution. The Scythian diversity crisis is followed by a rapid, steady increase with a peek in the Carnian. The diversity drops in the Norian and remains low in the Rhaetian. The evolution of gastropod palaeo-diversity and the role of mass extinctions for the evolution of the Gastropoda are subjects of this project. The database for the Permian is under construction. My co-worker is Doug Erwin from the Smithsonian Institution

 

Evolution of the Late Palaeozoic Caenogastropoda

 

The subclass Caenogastropoda is the most diverse group of the Recent Gastropoda. The first undoubted caenogastropods are from the Late Palaeozoic. Caenogastropods can have planktotrophic larval development and larval shells are commonly ornamented in a characteristic way. Therefore, protoconch morphology can be very informative in terms of systematics and larval ecology. Protoconch preservation is very rare in the Palaeozoic. However, in some faunas of the U.S.A. and Australia such well-preserved material is available. This increases the number of shell characters and therefore the significance of phylogenetic analyses.

 

Pseudozygopleurid gastropod
Imogloba sp. sideview
Imogloba sp. apical view

The Mistelgau Project

 

In a clay pit near the small village of Mistelgau (Upper Franconia, Germany) a unique section from the Pliensbachian to the Early Aalenian is exposed. The ammonite stratigraphy was studied by Chris Schulbert. The section also contained a rich microgastropod assemblage, especially in the Late Toarcian to Early Aalenian period. During that period the assemblages changed considerabely in composition and diversity. This has major implications for the knowledge of the Pliensbachian/Toarcian extinction event in this region.

 

Jurassic (Pliensbachian, Toarcian, Aalenian) gastropod faunas from Franconia (Southern Germany)

 

Gastropods are commonly the most abundant and diverse group in early Mesozoic fine-grained dark shales. Nevertheless, gastropods are largely neglected in palaeoecological studies of this facies. Ongoing collections in the Jurassic of Franconia have resulted in rich well-preserved material and abundance data. My co-workers are Chris Schulbert (Universität Erlangen) and Joachim Gründel (Freie Universität Berlin).

 

Revision of the Early Triassic gastropod fauna of the Moenkopi Formation (Utah, USA) ? recovery of gastropod faunas after the Permian/Triassic Mass Extinction Event

 

The monograph on the Moenkopi snails of Batten & Stokes (1986) is one of the most important publications on Early Triassic gastropods. The Moenkopi fauna (Locality) represents the most diverse gastropod fauna from the P/T-post extinction interval. Since the monograph of Batten and Stokes, more information about several Triassic gastropod genera has become known. This allows a more substantial placement of the Moenkopi snails and sheds light on the gastropod recovery in the aftermath of the end-Permian mass extinxtion event. In April 2003 my colleague Chris Schulbert, Roger Batten and I went to the Moenkopi Formation in order to resample the site. We have recovered abundant and well-preserved gastropods such as Cylindrobullina convexa, the oldest opisthobranch, Battenizyga eotriassica, numerous naticopsids representing several species as well as a variety of other gastropods.  The gastropods occur in shallow water, sub- to intertidal calcareous deposits e.g., in oolithes and tempestites. Bivalves are also abundant and relatively well-preserved. Occasionally, stromatolithes grow on gastropod shells. According to Schubert and Bottjer, larger stromatolithes in normal marine environments (more or less normal salinity) represent a disaster phenomenon in the aftermath of mass extinctions.

 

Planorbid evolution in the Miocene fresh water Lake of Steinheim (Germany)

 

The amazing endemic radiation of planorbids in the palaeo-ancient lake of Steinheim am Albuch has puzzled scientists for about 150 years. Lake Steinheim was an isolated meteor-crater lake that existed for some hundred thousand years. A highly endemic, diverse planorbid fauna evolved. The fossil record is very complete throughout the lake´s sediments. Speciation processes can be studied in detail. Ecophenotypy vs. true speciation and sympatric speciation are the main problems in the discussions. Coworker: Klaus Bandel (Universität Hamburg).

 

Phylogeny of the Ptenoglossa

 

This was my dissertation project. The Ptenoglossa are a highly diverse order of the Caenogastropoda. I studied Recent representatives of the ptenoglossan superfamilies Janthinoidea, Cerithiopsoidea, and Triphoroidea and reported the shell and radula morphology of numerous species. I traced back important phylogenetic lineages through time and found closely related species in the Palaeogene, Late Cretaceous, Late Triassic (Zygopleuridae, Protorculidae), and in the Late Palaeozoic (Pseudozygopleuridae). A phylogenetic hypothesis was based on characters of the Recent ptenoglossans and a fossil record of about 300 million years. My advisor was Klaus Bandel (Universität Hamburg).