One More Head Post

In Luoping County in the Yunnan province of China in 2016 the newest fossil of Atopodentatus was discovered. That fossil, as we have seen, offered a very different perspective of the way that the jaws looked in this animal. That change, as we mentioned, required a new interpretation of how Atopodentatus was able to feed and what it fed on. Previously, the initial description described a filter-feeding marine reptile that pushed its head into the muddy bottom of its environment and push out the sediment, filtering that sediment and water in hopes that it would trap small arthropods hiding in the sediments. In the newer description, the change in the dental landscape called for a new interpretation. Instead, the new hypothesis proposed by Chun et al. 2016 (https://advances.sciencemag.org/content/2/5/e1501659) detailed a mechanism in which the the small chisel-shaped teeth were used to scrape algal growths from rocks, plants, and other details of the underwater scenery. The authors also hypothesized that the more posterior teeth were capable of of helping to break up plants so as to be able to retrieve the algae from these materials as well.

As we can see from the paper, two new skulls were described, providing extra information about the organization of the mouth and face of Atopodentatus. These two skulls, in addition to the original (type) specimen allow for a very well defined reconstruction of the skull. Putting those three views of this animal together we end up with a reconstruction that fairly accurately portrays the actual organization of this animal. That allows us to better understand how it fed, how it swam (heads do have an aerodynamic property in all fluids after all), and possibly even how these animals may have interacted with one another. Could they bite each other in territorial disputes? Did they groom themselves, or one another on the beaches? Could they even get to the beaches? Remember, there is evidence of flipper-like digits on their limbs and we have not really determined their ability to "haul out" onto the beach in the first place. The head tells us a lot about behavior, but there is still more to this animal. We will look beyond the head tomorrow, so look at the fossils and reconstructions and consider what we might be able to glean from the bones and the interpretations of those bodies.