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| Oriensmilus liupanensis Wang, White & Guan, 2020 |
Abstract
Since the early 2000s, a revival of a felid relationship for barbourofeline sabretooths has become popular due to recent discoveries of fragmentary fossils from Africa. According to this view, barbourofelines trace their common ancestor with felids through shared similarities in dental morphology going back to the early Miocene of Africa and Europe. However, whether or not such an idea is represented in the basicranial morphology, a conservative area of high importance in family-level relationships, is yet to be tested. A nearly complete skull of Oriensmilus liupanensis gen. and sp. nov. from the middle Miocene Tongxin Basin of northern China represents the most primitive known barbourofeline with an intact basicranial region, affording an opportunity to re-examine the relationship of felids and nimravines. We also present an update on East Asian records of barbourofelines. The new skull of Oriensmilus possesses a suite of characters shared with nimravines, such as the lack of an ossified (entotympanic) bullar floor, absence of an intrabullar septum, lack of a ventral promontorial process of the petrosal, presence of a small rostral entotympanic on the dorsal side of the caudal entotympanic, and a distinct caudal entry of the internal carotid artery and nerve that pierces the caudal entotympanic at the junction of the ossified and unossified caudal entotympanics. The absence of an ossified bullar floor in O. liupanensis and its presence in those from the middle Miocene of Sansan, France thus help to bracket the transition of this character, which must have happened in the early part of the middle Miocene. Spatial relationships between bullar construction and the middle ear configuration of the carotid artery in Oriensmilus strongly resemble those in nimravines but are distinctly different from felids and other basal feliforms. Despite the attractive notion that early barbourofelines arose from a Miocene ancestor that also gave rise to felids, the basicranial evidence argues against this view.
Keywords: Barbourofelinae, basicranium, phylogeny, Tongxin, Cenozoic, Asia
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| Skull of Oriensmilus liupanensis (IVPP V25220, holotype) from Gunziling, Tongxin County in A, right lateral; and B, dorsal views. |
Order Carnivora Bowdich, 1821
Family Nimravidae Cope, 1880
Subfamily Barbourofelinae Schultz, Schultz and
Martin, 1970
Oriensmilus gen. nov.
Type and only species. Oriensmilus liupanensis gen.
and sp. nov.
Etymology. ‘Oriens’, Latin for rising (of the sun), commonly referring to East Asia; ‘smile’, Greek for carving
knife, in allusion to the long canine tooth of barbourofelines.
Oriensmilus liupanensis sp. nov.
1841 Sansanosmilus palmidens (Blainville); Chen & Wu
1976, 7.
2013b Sansanosmilus sp. (Qiu et al.); Wang et al. 2016,
798, fig. 4G.
Etymology. Refers to the Liupan Mountains (Liupan
Shan); the Tongxin Basin is located at the northern foothills of the Liupan Mountains.
Type locality and horizon. IVPP V25220 is from
Gunziling, about 10–12 km south of the small village
Dingjia’ergou (Qiu et al. 2013b, p. 59) in the Tongxin
Basin, Tongxin County, Ningxia Hui Autonomous
Region; upper part of Zhang’enbao Formation (Fig. 1).
Xiaoming Wang, Stuart C. White and Jian Guan. 2020. A New Genus and Species of Sabretooth, Oriensmilus liupanensis (Barbourofelinae, Nimravidae, Carnivora), from the middle Miocene of China suggests Barbourofelines are Nimravids, not Felids. Journal of Systematic Palaeontology. 18, 9. DOI: 10.1080/14772019.2019.1691066
