In modern times there are only a handful of mammals that belong to the same family as the horse, including horses, donkeys, and zebras. However, millions of years ago, hypomorph mammals were much more diverse than they are in modern times. Paleontologists have now discovered two new extinct pseudo-horse mammals that lived about 37 million years ago.
A recent study describes the two new species of palaeotheriidae mammals that lived in the subtropical landscape of Zambrana 37 million years ago. Researchers describe the new species dubbing them ‘Leptolophus cuestai’ and ‘Leptolophus franzeni’. Palaeotheriidae are mammals that are similar in terms of body shape to modern horses but were smaller in size.
The creatures would’ve been similar to horses with three toes but would’ve been the size of a fox terrier, a Great Dane, and a donkey living in a subtropical climate. Researchers note that the two new species not only expand fossil records and the biodiversity of palaeotheriidae but also display dental features that are atypical for equids of the Eocene period.
Their molars are described as having a very high crown and being covered by a thick layer of cementum. This particular type of teeth are also present in other Iberian palaeotheriidae and could be indicative of a difference in environmental conditions between Iberian and Central European areas.
Modern horses appeared in Europe during the Miocene and featured dentition with high crowns adapted for eating vegetation with high grit content, such as grasses. It’s unclear if the researchers discovered only teeth or if they discovered larger fossilized bones. It’s interesting that equids were so much more diverse in the distant past than they are today. The paper on the new mammals was published in the “Journal of Vertebrate Paleontology,” and Leire Perales-Gogenola led the study.