Acamptonectes

Name: Acamptonectes ‭(‬Rigid swimmer‭)‬.
Phonetic: Ah-camp-toe-nek-teez.
Named By: Valentin Fischer,‭ ‬Michael W.‭ ‬Maisch,‭ ‬Darren Naish,‭ ‬Ralf Kosma,‭ ‬Jeff Liston,‭ ‬Ulrich Joger,‭ ‬Fritz J.‭ ‬Krüger,‭ ‬Judith Pardo Pérez,‭ ‬Jessica Tainsh and Robert M.‭ ‬Appleby‭ ‬-‭ ‬2012.‭
Classification: Chordata,‭ ‬Reptilia,‭ ‬Ichthyosauria,‭ ‬Ophthalmosauridae,‭ ‬Ophthalmosaurinae.
Species: A.‭ ‬densus‭ (‬type‭)‬.
Diet: Piscivore.
Size: Around‭ ‬3‭ ‬meters long.
Known locations: England‭ ‬-‭ ‬Cambridge Greensand‭ & ‬Speeton Clay Formations.‭ ‬Germany,‭ ‬Cremlingen.
Time period: Hauterivian through to Cenomanian of the Cretaceous.
Fossil representation: Several specimens but often of incomplete remains.

       The first specimen of Acamptonectes was discovered in‭ ‬1958‭ ‬from the Speeton Clay Formation,‭ ‬but was never officially described.‭ ‬A second specimen from this formation was recovered in‭ ‬1985.‭ ‬Early interpretations of Acamptonectes led to the conclusion that it was similar to Platypterygius,‭ ‬but a new discovery from Germany in‭ ‬2003‭ ‬was found to bear similarities to the‭ ‬1958‭ ‬material,‭ ‬a discovery that sparked fresh interest in the fossils.‭ ‬A fresh study that was a collaboration of all the palaeontologists involved with these specimens saw the formal creation of Acamptonectes as a valid genus,‭ ‬as well as realisation that it was actually more similar to ichthyosaurs like Ophthalmosaurus and Mollesaurus.
       The name Acamptonectes,‭ ‬which means‭ ‘‬rigid swimmer‭’‬,‭ ‬is a reference to the tightly packed cervical‭ (‬neck‭) ‬vertebra which means that Acamptonectes probably was not able to turn its head from side to side.‭ ‬Additionally the front half of the post cranial skeleton,‭ ‬particularly the strongly developed ribs also hint towards a very rigid forward body with the only real motion coming from the tail.‭ ‬This might suggest that Acamptonectes relied upon high forward speed in chasing down prey like fast swimming fish rather than trying to out manoeuvre them.‭ ‬This torpedo-like motion would be better suited for high speed as Acamptonectes would not experience unnecessary drag caused by the side to side swaying of a body in motion.‭ ‬Additional developments to reduce water resistance are the shallow snout and slender but sharp teeth that would have helped improve the overall streamlining of the body.

Further reading
- New Ophthalmosaurid Ichthyosaurs from the European Lower Cretaceous Demonstrate Extensive Ichthyosaur Survival across the Jurassic–Cretaceous Boundary. PLoS ONE 7 (1): e29234 - V. Fischer, M. W. Maisch, D. Naish, R. Kosma, J. Liston, U. Joger, F. J. Krüger, J. Pardo Pérez, J. Tainsh & R. M. Appleby - 2012.



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