An ancient sabertoothed vegetarian
Hi everybody! This has been another row of extremely busy weeks-months, with lots of interesting things I would have liked to share here and absolutely no time to do it!.
Among the many duties that have kept me chained to my drawing table (and graphic tablet…) has been an exciting assignment from National Geographic Magazine: to reconstruct the bizarre South American Therapsid Tiarajudens eccentricus. My reconstruction has appeared in the “NOW” section of this month’s issue of the American edition. The section does not seem to be updated in the Society’s Web site, but if you are a German speaker you may want to check the site of the German edition here:
In case you have not seen the Magazine yet, I include my reconstructions here:
The creature, described last year by Brazilian paleontologist Juan Carlos Cisneros and colleagues, honours its specific name in having an eccentric appearance indeed. And the most striking feature of its anatomy are its enormously elongated upper “canine” teeth.
For decades, paleontologists have scratched their heads looking at the skulls of sabertooth cats, wondering how (and wether) they could be able to open their jaws wide enough to bite with their oversized fangs, because even with their obvious anatomical adaptations for extreme gapes, sometimes the lenght of the sabers still appears excessive.
In the case of Tiarajudens, there is no need to scratch one’s head: adult individuals with full-sized tusks could not possibly open their mouths wide enough to bite with them!. So what was the use of their spectacular teeth? The rest of the dentition of Tiarajudens, both in front and behind its tusks, is adapted for a vegetarian diet, and the tusks were most likely for defence, for intraespecific fights and often just for show. One interesting parallel is the extant musk deer, a medium sized ruminant from Asia. The males have impressive fangs but the anatomy of their mouths is not especially well adapted for biting at large gapes, so what the animals often do during fights is just to stab at their oponents with their mouths closed. Such an action would be of little use for a predator intent on killing its prey, but since several centimeters of the tusk protrude under the chin it is more than fit for causing nasty wounds in a rival musk deer, and on occasion it could even help it fend off an attack from a predator.
As long as we restrict the use of the term “Sabertooth” to sabertoothed predators, as I think we should do, a creature like Tiarajudens certainly does not fit the bill. But it was a spectacular animal indeed!
Here is the reference for the original paper in Science:
Cisneros, J.C.; Abdala, F.; Rubidge, B.S.; Dentzien-Dias, D.; Bueno, A.O. (2011). “Dental Occlusion in a 260-Million-Year-Old Therapsid with Saber Canines from the Permian of Brazil”. Science 331: 1603–1605