A new Early Cretaceous lamniform shark (Chondrichthyes,Neoselachii) |
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Authors: | JÜRGEN KRIWET STEFANIE KLUG JOSÉ I. CANUDO GLORIA CUENCA‐BESCOS |
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Affiliation: | 1. Museum of Natural History, Department of Collection, Humboldt‐University Berlin, Invalidenstr. 43, 10115 Berlin, Germany;2. Museum of Natural History, Department of Research, Humboldt‐University Berlin, Invalidenstr. 43, 10115 Berlin, Germany;3. Grupo Aragosaurus, Universidad de Zaragoza, Facultad de Ciencias, c. Pedro Cerbuna 12, 50009 Zaragoza, Spain |
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Abstract: | Eoptolamna eccentrolopha gen. et sp. nov. (Chondrichthyes, Lamniformes) from the near coastal upper Barremian Artoles Formation (Early Cretaceous) of Castellote (northwestern Spain) is described on the basis of about 50 isolated teeth. This taxon represents one of the earliest lamniform sharks known to date. We hypothesize that most pre‐Aptian lamniforms belong to an ancient group characterized, amongst others, by a very weak gradient monognathic heterodont dental pattern, and by tearing‐type dentition. There is a nutritive groove in the lingual root protuberance in juveniles of Eoptolamna, which persists in adults. A single pair of symphysial and a pair of upper intermediate teeth might have been present. Consequently, a new family, Eoptolamnidae, is introduced to include the new form, as well as Protolamna and probably Leptostyrax. The Eoptolamnidae represent an ancient family within Lamniformes. The origin of lamniform sharks remains, however, ambiguous despite recent advances. The new Spanish taxon is widespread in the Barremian of north‐eastern Spain, and occurs in a wide range of facies from near‐coastal to lake deposits. This lamniform also occurs in the Lower Cretaceous of northern Africa. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154 , 278–290. |
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Keywords: | Eoptolamna Eoptolamnidae Leptostyrax morphology plesiomorphic condition Protolamna |
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