Previously, plant eating lizards were known from around 205 million years ago,so this new find, clocking in at closer to 300mya, is an important extension of this lineage.
These lizards are related to the mammal-like reptiles that are, in turn, ancestral to mammals.
The teeth show plant eating, and in particular, they show a morphology thought to be linked to a more specialized consumption of a higher quality, lower fiber diet. This is actually something I know something about, and for that reason, I’m going to reserve comment on this interpretation and its meaning until I’ve thought about it a bit more. But, we can probably take the researchers word for this at the moment. do have one provisional comments about the diet of Gordodon kraineri. It is small for a plant eating lizard, said from the teeth to be specialized in higher quality plant parts. For this reason, I wonder, is there any evidence of co-evolution between this lineage of specialist plant eaters and the plants they ate? There should be, might be hard to find, but probably worth looking for.
Gordodon kraineri is a new genus and species of edaphosaurid eupelycosaur known from an associated skull, lower jaw and incomplete postcranium found in the early Permian Bursum Formation of Otero County, New Mexico, USA. It has a specialized dental apparatus consisting of large, chisel-like incisors in the front of the jaws separated by a long diastema from relatively short rows of peg-like maxillary and dentary cheek teeth. The dorsal vertebrae of Gordodon have long neural spines that bear numerous, randomly arranged, small, thorn-like tubercles. The tubercles on long neural spines place Gordodon in the Edaphosauridae, and the dental apparatus and distinctive tubercles on the neural spines distinguish it from the other edaphosaurid genera—Edaphosaurus, Glaucosaurus, Lupeosaurus and Ianthasaurus. Gordodon is the oldest known tetrapod herbivore with a dentary diastema, extending the temporal range of that anatomical feature back 95 million years from the Late Triassic. The dental apparatus of Gordodon indicates significantly different modes of ingestion and intraoral transport of vegetable matter than took place in Edaphosaurus and thus represents a marked increase in disparity among edaphosaurids. There were two very early pathways to tetrapod herbivory in edaphosaurid evolution, one toward generalized browsing on high-fiber plant items (Edaphosaurus) and the other (Gordodon) toward more specialized browsing, at least some of it likely on higher nutrient, low fiber plant items. Gordodon shows a surprisingly early specialization of the dental apparatus and indicates how incomplete our knowledge is of edaphosaurid evolution, disparity and diversity.
Artist’s reconstruction of the new fossil find about to eat a plant, in a specialized manner:
The original paper is available as an OpenAccess paper at Palaeontological Electronica.
Full Reference: Spencer G. Lucas, Larry F. Rinehart, and Matthew D. Celeskey. The oldest specialized tetrapod herbivore: A new eupelycosaur from the Permian of New Mexico, USA. Article number: 21.3.39