Distinct Species of Horses, and Illusions from Tooth Wear – #365papers – 2017 – 121

#365papers for May 1, 2017

Li, Deng, Hua, Ki, and Zhang, 2017, Assessment of dental ontogeny in late Miocene hipparionines from the Lamagou fauna of Fugu, Shaanxi Province, China: PLoSONE v. 12, e0175460.

What’s it about?

Hipparionines are a branch of fossil horses that include the genus Hipparion. Horse molars have complex ridges, basins, and swirly walls of enamel. The relationships, sizes, and shapes of these structures are used to distinguish among the various species of horses. The authors here examine the teeth of two ‘different’ species of Hipparion, using observation of complete specimens at various stages of wear, looking at whole jaws in cross-section using spiral computed tomography (CT), and by selecting several teeth to literally slice up to examine the changes in tooth enamel shapes over the height of the tooth.

Why does it matter?

The shapes of the ridges, basins, and swirls in a single tooth change along the height of the tooth. Since it is these shapes that are used to define species, it’s possible that species are mis-identified and that some ‘species’ are simply more aged and worn members of another species.

Why did I read this?

Horses. That is all.

But seriously, this paper does do a fantastic job of labeling all the structures of horse teeth, so would be a valuable reference for anyone getting started with horse tooth morphology.