A fishy mosasaur: the axial skeleton of Plotosaurus (Reptilia, Squamata) reassessed

Summary, in English

The concept of convergence, that is, how unrelated animals independently evolve similar morphological traits, is a fundamental aspect of evolution. Hitherto, the Mesozoic ichthyosaurs were regarded as the sole obligate marine reptiles that achieved a fully streamlined body and a semilunate tail fluke. However, analyses of vertebral centrum morphometrics and process orientation have revealed that a subsequent clade of secondarily aquatic reptiles, the mosasaurs (here exemplified by the advanced, mid-Maastrichtian mosasaurine Plotosaurus), had developed a deep, fusiform body and a probable pursuit-predatory behaviour by the time of their sudden extinction at the Cretaceous-Paleogene boundary. Stringent physical constraints and selection pressures, imposed by the surrounding water, probably were responsible for this spectacular example of large-scale evolutionary convergence.

• Författare: Johan Lindgren; John W. M. Jagt; Michael W. Caldwell
• Avdelning/ar: Berggrundsgeologi
• Publiceringsår: 2007
• Språk: Engelska
• Sidor: 153-160
• Publikation/Tidskrift/Serie: Lethaia
• Volym: 40
• Issue: 2
• Länkar: http://dx.doi.org/10.1111/j.1502-3931.2007.00009.x
• Dokumenttyp: Artikel i tidskrift
• Förlag: Taylor & Francis
• Ämne: Geology
• Nyckelord: tail stock; tail fin; surface; propulsive; Plotosaurus; Mosasauridae; displacement unit; hypocercal
• Status: Published
• ISBN/ISSN/Övrigt: ISSN: 0024-1164