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A new species of extinct bullhead sharks, Paracestracion viohli sp. nov. (Neoselachii, Heterodontiformes), from the Upper Jurassic of South Germany

100%

Kriwet J.

Acta Geologica Polonica

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2008

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tom Vol. 58, no. 2

235-241

EN

The early history of heterodontid sharks is documented mainly by isolated teeth. So far, three different heterodontid genera have been recorded from the Jurassic: Proheterodontus from the Middle Jurassic of England (and probably Upper Jurassic of France), Paracestracion from the Early to Late Jurassic of England, Belgium and S. Germany, and Heterodontus from the Upper Jurassic of South Germany. Paracestracion is known by isolated teeth in the Early and Middle Jurassic and by articulated skeletons in the Late Jurassic. Recently discovered skeletal remains from the upper Kimmeridgian locality of Schamhaupten, S. Germany, represent a new, hitherto unknown extinct species of Paracestracion, P. viohli sp. nov., which documents further taxonomic diversity of early heterodontids. This new taxon is represented by a subadult individual as indicated by the absence of molariform lateral teeth; it shares with other species of Paracestracion the characteristic holaulacorize cuspidate teeth. It differs from all other species in having ornamented lingual crown faces. Teeth of Proheterodontus differ in a different tooth root vascularisation. Proheterodontus and Paracestracion vanished before or at the Jurassic/Cretaceous boundary with Heterodontus becoming progressively more diverse in the Cretaceous and Cenozoic.

2

Neoselachian remains [Chondrichthyes, Elasmobranchii] from the Middle Jurassic of SW Germany and NW Poland

100%

Kriwet J.

Acta Palaeontologica Polonica

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2003

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tom 48

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nr 4

EN

New neoselachian remains from the Middle Jurassic of SW Germany and NW Poland are described. The locality of Weilen unter den Rinnen in SW Germany yielded only few orectolobiform teeth from the Aalenian representing at least one new genus and species, Folipistrix digitulus, which is assigned to the orectolobiforms and two additional orectolobiform teeth of uncertain affinities. The tooth morphology of Folipistrix gen. nov. indicates a cutting dentition and suggests specialised feeding habits. Neoselachians from Bathonian and Callovian drill core samples from NW Poland produced numerous selachian remains. Most teeth are damaged and only the crown is preserved. Few identifiable teeth come from uppermost lower to lower middle Callovian samples. They include a new species, Synechodus prorogatus, and rare teeth attributed to Palaeobrachaelurussp., Pseudospinax? sp., Protospinax cf. annectans Woodward, 1919, two additional but unidentifiable Protospinax spp. and Squalogaleussp. Scyliorhinids are represented only by few isolated tooth crowns. No batoid remains have been recovered. The two assemblages contribute to the knowledge about early neoselachian distribution and diversity.

3

New insight into the distribution and palaeobiology of the pycnodont fish Gyrodus

63%

Kriwet J. , Schmitz L.

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nr 1

EN

The pycnodont fish Gyrodusis reported for the first time from the Lower Cretaceous of Germany based on two lower jaw elements from the Hauterivian and Barremian. The stratigraphic and geographic distribution of Gyrodus is summarized. Gyrodusranges from the Middle Jurassic to the Early Cretaceous making it one of the longest living pycnodonts. Unambiguous Late Cretaceous records of Gyrodus are still missing. Gyrodus displays its widest distribution and greatest taxonomic diversity in the Late Jurassic. The distribution of Gyrodusimplies not only near−coastal mode of life but also a pelagic lifestyle conversely to most other pycnodonts. External body features and function of the unpaired fins support this interpretation.

4

New Eocene Antarctic chimeroid fish [Holocephali, Chimaeriformes]

63%

Kriwet J. , Gazdzicki A.

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nr 1

5

A partial skeleton of a new lamniform mackerel shark from the Miocene of Europe

51%

Kriwet J. , Mewis H. , Hampe O.

Acta Palaeontologica Polonica

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2015

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tom 60

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nr 4

EN

Cenozoic lamniform sharks are mostly represented by isolated teeth and vertebrae, whereas articulated skeletal remains are usually very scarce. Here, we describe a partial skeleton of an extinct lamniform shark consisting of 42 slightly disarticulated teeth, 49 vertebrae, and additional unidentifiable cranial and postcranial remains. The specimen originates from the Miocene mica-clay of Groß Pampau (North Germany), which is of late Langenfeldian age (= Serravallian-Tortonian boundary; middle-late Miocene). A total of 13 measurements of each tooth, as well as morphological features, were used to reconstruct the dentition of this specimen and to provide detailed taxonomic information. Additionally, the total body size and age at death were established using methodologies based on vertebral and tooth measurements and vertebral centra growth ring counts, respectively. The specimen undoubtedly represents the most complete individual of "Carcharodon (= Isurus) escheri", previously known only from a few isolated teeth. The dental pattern (e.g., marked dignathic and monognathic heterodonty patterns; only slightly labio-lingually compressed upper teeth; upper teeth slender with distally inclined or curved main cusps; massive, hook-like upper intermediate tooth; main cusps with crenulated cutting edges; lateral cusplets in teeth of all ontogenetic stages) clearly separates this shark from all hitherto known Cenozoic and Recent lamnids and a new genus, Carcharomodus, consequently is introduced. Carcharomodus escheri comb. nov. is a characteristic element of late early Miocene to the Pliocene Western and Central European fish faunas. All previously identified Pacific occurrences represent a different taxon. We estimate that the specimen had a total body length of about 4 m and that it was older than 10 years and thus might have reached maturity before death, as indicated by all available evidence.