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.
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
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.
- 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.