Name: Atopodentatus ‭(‬strange toothed‭)‬.
Phonetic: Ah-top-o-den-tah-tus.
Named By: L.‭ ‬Cheng,‭ ‬X.‭ ‬H.‭ ‬Chen,‭ ‬Q.‭ ‬H.‭ ‬Shang‭ & ‬X.‭ ‬C.‭ ‬Wu‭ ‬-‭ ‬2014.
Classification: Chordata,‭ ‬Reptilia.
Species: A.‭ ‬unicus‭ (‬type‭)‬.
Diet: Carnivore/Sediment filter feeder.
Size: About‭ ‬3‭ ‬meters long.
Known locations: China,‭ ‬Yunnan Province.
Time period: Ansian of the Triassic.
Fossil representation: Single specimen.

       Atopodentatus was a semi-aquatic marine reptile known to have lived in what is now China during the mid Triassic.‭ ‬This was a time‭ ‬that saw a great radiation in marine reptile forms,‭ ‬but Atopodentatus has still managed to surprise everyone even after over two hundred years of paleontological study.‭ ‬The forward portion of the jaws hook down to give a bent shape to the mouth which looks kind of bizarre but‭ ‬is still‭ ‬within known parameters of natural science.‭ ‬Then Atopodentatus takes things a step further in that the upper jaw splits down its centre as the teeth continue to grow up the divide to give the appearance of a‭ ‘‬toothed zipper‭’ ‬on the front of the snout.
       This bizarre form of mouth is thought to have been an extreme adaptation for a filter feeding lifestyle,‭ ‬where Atopodentatus would swim down to the soft sediment of the sea floor,‭ ‬pick up a mouth full of sediment,‭ ‬and then allow the fine grains to pass out between the mesh formed by the teeth,‭ ‬while any small burrowing vertebrates would be trapped within before being consumed.
       With such a bizarre head,‭ ‬it is easy to overlook the body,‭ ‬but the body of Atopodentatus does support the semi-aquatic lifestyle hypothesis.‭ ‬The neck was not especially long,‭ ‬and the limbs were very robust in form,‭ ‬strong indications that Atopodentatus would leave the water and rest on shore when not feeding in the water.‭ ‬As such Atopodentatus were likely restricted to foraging in coastal waters where they had both an abundance of available food and areas where they could rest.‭
       When in the water,‭ ‬Atopodentatus may have been hunted by large hyper-carnivorous ichthyosaurs similar in form to Himalayasaurus and Thalatoarchon‭ (‬known from Asia and North America respectively‭)‬,‭ ‬as well as large prehistoric sharks.‭ ‬When on land Atopodentatus may have been at risk of attack from‭ ‬the‭ ‬larger archosaurs of the time.

Further reading
-‭ ‬A new marine reptile from the Triassic of China,‭ ‬with a highly specialized feeding adaptation.‭ ‬-‭ ‬Naturwissenschaften.‭ ‬-‭ ‬L.‭ ‬Cheng,‭ ‬X.‭ ‬H.‭ ‬Chen,‭ ‬Q.‭ ‬H.‭ ‬Shang‭ & ‬X.‭ ‬C.‭ ‬Wu‭ ‬-‭ ‬2014.


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