Research projects of the Mollusca Section

Systematics, biogeography, evolution and biology of Opisthobranchia from Chile and the Southern Ocean.

Primary aim was an inventory of the coastal nudipleuran (Nudibranchia plus Pleurobranchoidea) fauna of Chile and southern Argentina, the taxonomic revision of relevant species and groups, and the biogeographic analysis of distributional data. Extensive material was collected (mainly by Scuba-divers), examined by anatomical and histological means, and critically compared with available museum and type material. The monographical “Catalog of Chilean and Magellanic Nudipleura” presents diagnoses, illustrations, and taxonomical comments of all species known at present, as well as an identification key that can be used in the field.

Close cooperations exist with PD Dr. H. Wägele (Bonn), Prof. Dr. S. Millen (Vancouver), and with Dr. Vreni Häussermann and Günther Försterra (www.huinay.cl).

Future studies will focus on the opisthobranch fauna of Easter Island (with Prof. Dr. Luis DiSalvo, Coquimbo), the Juan Fernández Islands (with Dr. Bieler, Chicago), south Chilean fjords, Peru (see Point 8), South Georgia and other subantarctic islands, and on Antarctica (see Point 7).

Literature

SCHRÖDL, M. 1996. Nudibranchia y Sacoglossa de Chile: Morfología exterior y distribución. Gayana Zoología 60(1):17-62.

SCHRÖDL, M. 2003. Sea slugs of Southern South America. ConchBooks, Hackenheim. 165pp.

Phylogeny of basal opisthobranchs

Concentrates on the (micro-) anatomical, histological and ultrastructural study of presumably basal and enigmatic nudibranch groups such as Doridoxa, Heterodoris and Corambe (together with PD Dr. H. Wägele, Bonn). Using new characters, improved structural analysis and computer-based analytical methods we intend to reconstruct the relationships of major clades within the Nudibranchia. At present we are performing molecular analyses of the  18S and 28S genes of a wide variety of opisthobranchs in order to conclude on the phylogeny of major opisthobranch clades (DFG grant to PD Dr. H. Wägele & M. Schrödl).

Literature

SCHRÖDL, M. & H. WÄGELE. 2001. Anatomy and histology of Corambe lucea Marcus, 1959 (Gastropoda: Nudibranchia), with discussion of the systematic position of Corambidae. Organisms, Diversity & Evolution 1: 3-16.

SCHRÖDL, M., WÄGELE, H. & R.C. WILLAN. 2001. Revision of the enigmatic nudibranch family Doridoxidae Bergh, 1899 (Mollusca: Opisthobranchia) with discussion of basal nudibranch phylogeny. Zoologischer Anzeiger 240: 83-97.

VONNEMANN, V., M. SCHRÖDL, A. KLUSSMANN-KOLB & H. WÄGELE. In press. Reconstruction of the Phylogeny of the Opisthobranchia (Mollusca, Gastropoda) by means of 18S and 28S rDNA Sequences. Journal of Molluscan Studies.

Monoplacophora and basal molluscan phylogeny

More than 50 years after the discovery of living monoplacophorans in the deep sea these rarely found “living fossils” still are especially fascinating to zoologists. We are investigating the geographic distribution, anatomy and biology of Antarctic species. Morphological and molecular datasets are used to conclude on the phylogeny and evolution of monoplacophorans (with Prof. Dr. G. Haszprunar, ZSM; Prof. Dr. G. Giribet, Harvard).

Literature

GIRIBET, G., A. OKUSU, A.R. LINDGREN, S.W. HUFF, M. SCHRÖDL & M.K. NISHIGUCHI. 2006. Evidence for a clade composed of molluscs with serially repeated structures - monopolacophorans are related to chitons. Proceedings of the National Academy of Sciences.

SCHRÖDL, M. 2006. Laevipilina theresae, a new monoplacophoran species from Antarctica. Spixiana 29: 225-227.

SCHRÖDL, M., LINSE, K. & SCHWABE, E. 2006. Review on the distribution and biology of Antarctic Monoplacophora, with first abyssal record of Laevipilina antarctica. Polar Biology 29: 721-727.

Opisthobranchia of Brazil

Bioinventory of Brazilian seaslugs (with S. Riedl), as well as revision of the rediscovered opisthobranch (type) collection of Ernst and Eveline Marcus (in cooperation with C. Magenta and Dr. L. Simone, Zoological Museum São Paulo).

Literature

DaCOSTA, S., MAGENTA, C., SIMONE, L.R.L. & M. SCHRÖDL. In review. Computerbased 3-dimensional reconstruction of major organ systems of a new Flabellina species from Brazil (Nudibranchia: Aeolidoidea).

JÖRGER, K., NEUSSER, T.P. & M. SCHRÖDL. In press. Redescription of female Pontohedyle brasilensis (Rankin, 1979), a junior synonym of the Mediterranean P. milaschewitchii (Kowalevsky, 1901). Bonner Zoologische Beiträge.

Systematics and phylogeny of interstitial gastropods

(K. Jörger, T.P. Neusser, I. Rückert & M. Schrödl)

As a case study we are exploring the phylogeny and evolution of small though biologically and structurally extremely diverse groups of opisthobranchs, with special focus on Acochlidia (DFG Projekt SCHR 667/4). A worldwide inventory aims to cover most recent diversity possible. Our main task is a comparative in-depth exploration of all characters with potential phylogenetic signal. Adult and ontogenetic stages are thus studied using all available methods such as computer-based 3D reconstruction of all major organ systems. Electron microscopy is applied to reveal ciliation patterns on body surfaces, to reliably document most tiny radular structures and to explore the novel set of sperm characters in Acochlidia. Immunocytochemical staining techniques in combination with confocal laser scanning analysis allow spectacular insights e.g. into the development of muscle and nervous systems. We are on the way to exemplarily uncover the evolution of characters under extreme environmental i.e. mesopsammic conditions, and to reliably reconstruct the phylogeny and phylogeography of a mesozooic group. On longer terms, we will use data on our model groups to test possibilities and limitations of phylogenetic methods and evolutionary conclusions.

Literature

SOMMERFELDT, N. & M. SCHRÖDL. 2005. Microanatomy of Hedylopsis ballantinei, a new interstitial acochlidian gastropod from the Red Sea, and its significance for phylogeny. Journal of Molluscan Studies 71: 153-165.

NEUSSER, T.P., HESS, M., HASZPRUNAR, G., & SCHRÖDL, M. 2006. Computerbased 3-dimensional reconstruction of the anatomy of Microhedyle remanei (Marcus, 1953), an interstitial acochlidian gastropod from Bermuda. Journal of Morphology 267: 231-247.

NEUSSER, T.P., HESS, M., HASZPRUNAR, G., & SCHRÖDL, M. 2007. Spermatozoa ultrastructure of Microhedyle remanei (Marcus, 1953), an interstitial acochlidian gastropod from Bermuda. Journal of the Marine Biological Association of the UK 87: 747-754.

NEUSSER, T.P. & M. SCHRÖDL. 2007. Tantulum elegans reloaded: a computer-based 3D-visualization of the anatomy of a Caribbean freshwater acochlidian gastropod. Invertebrate Biology 126: 18-39.

JÖRGER, K., NEUSSER, T.P., HASZPRUNAR, G. & M. SCHRÖDL. In press. Undersized and underestimated: 3D-visualization of the Mediterranean interstitial acochlidian gastropod Pontohedyle milaschewitchii (Kowalevsky, 1901). Organisms, Diversity & Evolution.

Opisthobranchs’ parasites: systematics, biology and evolution of endoparasitic Splanchnotrophidae (Copepoda)

(M. Schrödl, A. Salmen & N. Wilson)

These studies deal with the occurrence, morphology and taxonomy of splanchnotrophid copepods, especially of the genus Ismaila, and with the biology and evolution of parasite-host associations. Results of former work indicate that nudibranch-splanchnotrophid associations may serve as an appropriate model system to understand the evolution of parasitism in marine invertebrates.

Literature

SCHRÖDL, M. 1997. Aspects of Chilean nudibranch biology: Effects of splanchnotrophid copepod parasitism on Flabellina sp.1. Opisthobranch Newsletter 23(12):45-47.

SCHRÖDL, M. & U. HAUMAYR. 1999. Opisthobranchs‘ parasites: splanchnotrophid copepods of the genus Ismaila. International Workshop on Malacology, Menfi, Sicily, abstracts. 1 p.

SCHRÖDL, M. 2002. Heavy infestation by endoparasitic copepod crustaceans (Poecilostomatoida: Splanchnotrophidae) in Chilean opisthobranch gastropods, with aspects of splanchnotrophid evolution. Organisms, Diversity & Evolution 2: 19-26. Electronic supplement.

HAUMAYR, U. & M. SCHRÖDL. 2003. Revision of the endoparasitic copepod genus Ismaila Bergh, 1867, with description of eight new species (Copepoda, Poecilostomatoida, Splanchnotrophidae). Spixiana 26: 1-33.

SALMEN, A., WILSON, N.G. & M. SCHRÖDL. In review. Scanning electron microscopical description and biology of three new endoparasitic Ceratosomicola species from tropical Indo-Pacific nudibranch hosts (Crustacea, Copepoda, Poecilostomatoida). Spixiana.

Antarctic and deep-sea Mollusca

Expecting a dramatic global warming, the study of Antarctic ecosystems is of major interest. As a benchmark for assessing future changes we are investigating the Antarctic mollusc fauna in the framework of the "Census of Antarctic Marine Life (CAML)". Our recent analyses show deep sea trenches and abyssal planes off the Antarctic Penisula and the Scotia Arc to host a unique - and surprisingly species rich - abyssal gastropod fauna. These formerly unexplored areas have been sampled comparatively during the "Census of the Diversity of Abyssal Marine Life (CeDaMar)". All these activities are part of the largest international efforts ever to do an inventory of global marine biodiversity, the "Census of Marine Life (CoML)".

To facilitate future systematic and ecological work we are compiling a comprehensive "Atlas of Antarctic Mollusca". Apart from members of the ZSM Mollusca Section, a number of recognized experts are contributing to this multi-author project, e.g. Dr. L. Allcock, Belfast; Dr. K. Linse, British Antarctic Survey (BAS); Dr. M. Rauschert, Alfred Wegener Institut (AWI); Dr. B. Sirenko, St. Petersburg. Many of the several hundred species covered were collected during recent RV "Polarstern" expeditions to the Eastern Weddell Sea (EASIZ), to the Antarctic Peninsula and along the Scotia Arc (ANDEEP, LAMPOS). Observations and photographs on living specimens are supplemented by the description of preserved material including revisions of available museum and type specimens. Our studies will be further accelerated by participating the ANDEEP/SYSTCO Expedition, which is a substantial German contribution to the International Polar Year 2007/8 (IPY).

Literature

ENGL, W. & M. SCHRÖDL, eds. In prep. Atlas of Antarctic Mollusca. Groh, Conchbooks.

SCHWABE, E., BOHN, J.M, ENGL, W., LINSE, K. & M. SCHRÖDL. In press. Rich and rare - first insights into species diversity and abundance of Antarctic abyssal Gastropoda (Mollusca). Deep Sea Research II.

Biodiversity of Polyplacophora and Opisthobranchia of Costa Rica and Peru

(M. Schrödl and E. Schwabe)

We attempt an inventory and biogeographical analysis of these diverse though hardly explored Eastern Pacific coasts in collaboration with Dr. I. Wehrtmann, San José and S. Austermühle, Lima (Chitonen), and Yuri Hooker, Lima (Opisthobranchia).

Opisthobranchia and Polyplacophora of the Mediterranean Sea

Revision and illustration of the respective groups within the framework of the comprehensive book-project „R. Hofrichter: Das Mittelmeer“. Opisthobranchia:  M. Schrödl &; Polyplacophora: E. Schwabe. 

Literature

SCHRÖDL, M. & E. KÖHLER. 2001. Gastropteron rubrum not G. meckeli. Sea Slug Forum, Australian Museum (Rudman, W.B., ed.).

SCHRÖDL, M. & R. HOFRICHTER. 2003. Plattwurm oder Nacktschnecke? Pp. 690-692 In: Das Mittelmeer. Vol. 2. (Hofrichter, R., ed.). Spektrum Verlag. 859 pp.

Systematics of Polyplacophora

(E. Schwabe) The chiton fauna of several regions, especially of the Indo-West Pacific, is investigated and reviewed. In addition, the structure, development and evolution of several major organ systems (sensory organs, muscles, etc) of chitons are studied using adequate model organisms.