Long-term projects

Anatomy and taxonomy of Late Jurassic neoselachians

Late Jurassic neoselachians from the Lithographic Limestones (Oxfordian - Kimmeridgian) of S Germany are exceptional, because they are preserved as partial or complete skeletons. These specimens provide detailed information of morphological trades of apparently plesiomorphic taxa. Lamniform and squaliform sharks are not present before the Early Cretaceous (e.g., Kriwet & Klug in press; Kriwet et al. in press).

• Anatomy and phylogeny of synechodontiform sharks are the topic of a current PhD-project (S. Klug).

• Members of Heterodontiformes and Orectolobiformes are currently under study (J. Kriwet) to provide deeper insights into the evolution of modern galeomorph sharks.

• The identity of Hexanchiformes, Squatiniformes and batoid selachians is explored using different methods (meristics, morphology, cladistics) by J. Kriwet in cooperation with different colleagues (e.g. M. de Carvalho, Brazil) and some students of the FSR group (e.g. J. Dummasch).

• The systematic position of Carcharhniformes and Protospinax are examined using skeletal an meristic characters and employing different phylogenetic methods (J. Kriwet and S. Klug).

Diversity patterns of Mesozoic neoselachians

The aim of this project is to analyse faunal compositions and diversity fluctuations of neoselachians from the Early Jurassic to the Late Cretaceous and to establish their diversity, migratory, and biogeographic patterns during crucial periods (e.g., Jurassic-Cretaceous boundary, Cenomanian/Turonian).

J. Kriwet in cooperation with S. Klug, M. Benton (Bristol, U.K.) and W. Kiessling (Berlin, Germany)

Ontogeny of neoselachians

Ontogeny patterns of extinct and extant neoselachians form a major research topic of the current research group.

• K. Claeson analyses ontogenetic and embryological patterns in modern "hypnosqualean" sharks.

• J. Kriwet in cooperation with S. Tanaka, Shimizu, Japan is examining the early ontogenetic development of the frilled-shark Chlamydoselachus anguineus from Japanese waters.

• The development and growth of extinct neoselachians is analysed based on well-preserved and abundant skeletal remains from the Late Jurassic Lithographic Limestones of S Germany by J. Kriwet, S. Klug and various members of the FSR group.

Molecular genetics and adaptive radiations

The main objectives of this project are to understand cladogenetic and adaptive processes that generated and maintained past and modern diversities of neoselachians. So far, those studies are hampered by insufficient data and analyses. The main goals are to establish general patterns and models for adaptive traits and to identify intrinsic and extrinsic causes triggering special adaptations in neoselachians. Different methods for reconstructing phylogenetic patterns, cladogenetic events, rates of character and genome evolution, past diversity fluctuations and processes underlying these fluctuations, and diversification patterns are employed. Improved molecular clock approaches are used to establish the timing of cladogenetic events and the origin of special adaptations (e.g., deep-water and freshwater adaptations, filter-feeding). For this, fossil and extant taxa and different morphological and molecular data sets are analysed using total evidence approaches.

• K. Ermer: Adaptive traits in filter feeding sharks and rays (Chondrichthyes, Elasmobranchii): A multi-disciplinary approach.

• N. Straube: Evolution and adaptive radiation of dog-fish sharks (Chondrichthyes, Squaliformes).

• N. Hoffmann: Adaptive traits in Cenozoic freshwater batoids (Chondrichthyes, Elasmobranchii): A multi-disciplinary approach.

• B. Stelbrink: Molecular phylogeny and phylogeography of extant Angel sharks (Elasmobranchii, Squatiniformes).

Phylogeny of neoselachians - a multidisciplinary approach

The aim of this project is to re-evaluate the phylogeny of extant and fossil neoselachians using molecular, cranial and postcranial, and dental characters, and to analyse the value of skeletal characters in establishing a phylogeny of extant and fossil taxa. A supertree will be created using all available data to gain additional information on fossil and extant neoselachian interrelationships.

J. Kriwet and S. Klug

Character evolution in neoselachian history

The significance of characters used for identifying neoselachian taxa is a major topic of the FSR group uniting many of the individual student projects supervised by J. Kriwet (e.g. B. Stelbrink and J. Waligora). Character changes and their variability are explored employing fossil and extant specimens and various methodologies (e.g., ontogeny, morphometrics, cladistics, population and molecular analyses).

Extinct selachians from Spain and Portugal

The aim of this project is to investigate the taxonomy, diversity and palaeoenvironmental distributions of Late Jurassic to Late Cretaceous neoselachians faunas from the Iberian Peninsula. Amongst others geochemical tracer analyses performed on teeth will be compared to other neoselachians assemblages of Europe reconstructing general diversity patterns, which can be used as proxies for modern neoselachians distributions.

• Spain: J. Kriwet and S. Klug in cooperation with G. Cuenca-Bescos and J.I. Canudo (Zaragoza, Spain), N. López-Martínez (Madrid, Spain), E. Nunn (Plymouth, UK), M. Riley (UK), and S. Hölzl (Munich, Germany)

• Portugal: J. Kriwet and S. Klug in cooperation with W. Werner and S. Schneider (both Munich, Germany)

Antarctica

The purpose of this project is to analyse neoselachian and teleostean faunas and diversity patterns from the Cretaceous to Present of the Antarctic Peninsula and to reconstruct diversity fluctuations of post-Eocene Antarctic fishes based on isolated material from drilling-cores off the Antarctic Peninsula. Currently, the evolution and diversity of Eocene selachians and teleosteans are analysed.

J. Kriwet in cooperation with M. Lirio and H. Nuñez (both (Buenos Aires, Argentina), T. Hecht (Grahamstown, South Africa) and S. Klug

Peru

The aim of this long-term project is to analyse faunal successions of vertebrates from the middle Eocene to the early Pliocene from the Province of Ica and to reconstruct their evolutionary and adaptive histories. The focus is on articulated skeletal remains of large lamniform sharks from the Mio-Pliocene

J. Kriwet and S. Klug in cooperations with the Congreso de la República del Perú and additional scientific partners

Argentina

The aim is to evaluate the diversity changes of selachian assemblages in high latitudes across the K/T boundary and to identify possible effects of the K/T boundary event on the faunal assemblages. The focus is on Maastrichtian and Palaeogene assemblages from the provinces of Chubut and Neuquén.

J. Kriwet in cooperation with R. Scasso and F. Medina (Buenos Aires, Argentina) and M. Aberhan and W. Kiessling (Berlin, Germany)

Molasse Basin, S Germany

The goals of this project are to describe several neoselachian assemblages from the Mio-Pliocene Molasse basin of S Germany.

J. Kriwet in cooperation with B. Reichenbacher and S. Schneider (both Munich, Germany)