From a near-complete skull of the genus Palaeoryctes found in New Mexico, it is known that palaeoryctids were small, shrew-like insectivores with an elongated snout similar to that of the leptictids. However, in contrast to the latter, little is known about palaeoryctids' postcranial anatomy (the skeleton without the skull).[9] A 2024 study found shared cranial details between palaeoryctids and leptictids, suggesting a possible close relationship, plesiomorphic retentions, or convergent acquisitions.[10] Where the leptictids were short-lived, the palaeoryctids seem to have been ancestors of Eocene species. While their dental morphology still indicate a mostly insectivorous diet, it, to some extent, also relate to Eocene carnivores such as creodonts.[9]
Taxonomy and phylogeny
History of phylogeny
The relationship between this archaic group and other insectivorous mammals is uncertain.[11][12] Palaeoryctidae was originally assigned to the now-abandoned grouping Insectivora by Sloan and Van Valen (1965), then to clade Proteutheria,[7] and more recently to Eutheria by Scott et al. (2002).[13]
Generally speaking Palaeoryctidae has been used as a wastebasket taxon for many archaic insectivorous mammals.[14]
According to a 2022 study by Bertrand et al., palaeoryctids are identified to be a basal group of placental mammals.[15]
^A. O. Averianov (2003.) "Present-Day Concepts of the System of Placental Mammals." in: "Systematics, Phylogeny and Paleontology of Small Mammals", Ed. by A. O. Averianov and N. I. Abramson (Zool. Inst. Ross. Akad Nauk, St. Petersburg), pp. 15–20 [in Russian].
^ abGregg F. Gunnell, Thomas Bown, Jonathan Ivan Bloch, Doug M. Boyer (2008.) "Proteutheria"; pp. 63–81 in C. M. Janis, G. F. Gunnell, and M. Uhen (eds.), "Evolution of Tertiary Mammals of North America. Volume 2: Small Mammals, Xenarthrans, and Marine Mammals." Cambridge University Press, Cambridge, U.K.