J. Meng et al., THE CRANIAL MORPHOLOGY OF AN EARLY EOCENE DIDYMOCONID (MAMMALIA, INSECTIVORA), Journal of vertebrate paleontology, 14(4), 1994, pp. 534-551
An early Eocene didymoconid skull with perfect basicranial region from
Hubei Province of China is described. Important cranial features incl
ude a small orbit, a broad temporal region, a maxilla-frontal contact
in the orbit, absence of the jugal-lacrimal contact, a broad dorsal pr
ocess of the alisphenoid, an extensive squamosal, absence of the postg
lenoid foramen, a transversely elongate glenoid fossa, a fully ossifie
d bulla, an external auditory canal floored by the squamosal and masto
id of the petrosal, a greatly expanded mastoid of the petrosal, and a
large foramen for the epitympanic sinus in the tympanic roof. In addit
ion, the internal carotid artery may be reduced, although the stapedia
l artery is well developed. Analyses of the cranial features reveal th
at this skull is already highly specialized. The analyses also indicat
e that the North American genus Wyolestes and the Asiatic didymoconids
form a paraphyletic group and that derivation of both Wyolestes and d
idymoconids from a Paleocene Yantanglestes-like mesonychid is not supp
ortable. Instead, on the basis of cranial evidence, a didymoconid-inse
ctivore relationship is suggested.