Review and photographs by stemturtle, edited by Suspsy
Odontochelys semitestacea was a Triassic stem turtle whose fossils from 220 mya were found in Guizhou, China. It is the testudine equivalent of Archaeopteryx, transitional between Pappochelys and Proganochelys. What does this species tell us about the origin of turtles? We’ll get back to that question later.
Zhao Chuang and Yang Yang have created a beautiful PVC sculpture of Odontochelys for Item Number 25 of the PNSO miniature line. The length of the figure is 8.5 cm (3.3″), which is a scale of 1:4.7 for a 40 cm fossil. The main color is olive with four orange stripes down the back outlined with black. A black line runs through the eyes and down the neck and there are three black hash marks on the tail. The plastron is also olive, and marked with signatures by the artists and a production date of 2017. I would have preferred a more contrasting color scheme. Shallow dorsal grooves separate the five ribs, which are precursors to a carapace. The species name, semitestacea, refers to a half shell.
The plastron may have offered protection against predation from below. A semi-aquatic habitat is implied for Odontochelys instead of a terrestrial lifestyle. There is scaly texture on the legs and very slightly on the back, perhaps an indication of saurian ancestry. If speed were an issue, smooth skin would have been selected to reduce drag underwater.
The small head looks typically chelonian. Teeth were not sculpted because the mouth is closed. The mini-poster enclosed in the clamshell packaging shows tiny teeth on both jaws. The genus name, Odontochelys, translates to “toothed turtle.” Curiously, there is no beak, even though it was present in another stem turtle named Eorhynchochelys that was 10 million years older. One step backwards.
Odontochelys helps us understand how turtles evolved shells. What about turtle phylogeny? There is still no agreement about lepidosauromorph versus archosauromorph descent. Consensus requires more research. Meanwhile, this is now my favorite figure. PNSO’s care to detail elevates it from a toy to a work of art. It is currently available on Amazon.