A new genus and species of sabretooth,Oriensmilus liupanensis(Barbourofelinae, Nimravidae, Carnivora), from the middle Miocene of China suggests barbourofelines are nimravids, not felids

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 reexamine 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.

The largest hoplophonine and a complex new hypothesis of nimravid evolution

“…Within Hopliphoninae are found the genera Hoplophoneus , Eusmilus and Nanosmilus , while the remainder are within Nimravinae. Additionally, the Eocene–Oligocene Nimravinae was recovered in an arrangement that is more or less the direct opposite of prior analyses 1 , 4 , 5 , with the scimitar-tooth Dinictis felina as the basalmost taxon and ‘cheetah-like’ 23 Dinaelurus crassus as the most derived. Barbourofelini was recovered as a well-supported monophyletic clade with four unambiguous synapomorphies (93% PP) as sister to the North American and European Nimravus plus Dinaelurus clade, with three unambiguous synapomorphies (91% PP).…”

“…These comparisons resulted in the moniker of ‘false sabertooth cats’ for this group of carnivores, which until recently was thought to represent one of three independent acquisitions of sabertooth morphology within Carnivoramorpha. These studies have subsumed the “barbourofelids” into Nimravidae, as Miocene members of this family, based upon shared basicranial morphology, but the precise placement of these Miocene nimravids is still debated 1 – 3 .…”

“…All past phylogenetic analyses have cast these non-felid sabertooths as having an evolutionary history of increased acquisition of sabertooth morphology, resulting in pectinate relationships of the least sabertoothed taxa to the most 1 , 3 – 8 . This pattern may stem from a historical interest and resultant character selection of these sabertooth features, focusing on the dental aspects of nimravid anatomy, and the necessary cranial adaptations to wield saberteeth.…”

Eomakhaira molossus, A New Saber-Toothed Sparassodont (Metatheria: Thylacosmilinae) from the Early Oligocene (?Tinguirirican) Cachapoal Locality, Andean Main Range, Chile

“…EVOLUTION OF SABER TEETH IN SPARASSODONTA; Among eutherians, saber teeth have originated independently three or four times: in oxyaenid "creodonts" (Machaeroidinae), in nimravid and barbourofelid carnivoramorphans (if these are not sister taxa that were ancestrally machairodont; Wang et al, 2020), and in felid carnivorans (Machairodontinae) (Anton, 2013). Among metatherians, they are known to have evolved only once, in sparassodonts (suggestions that the extant didelphid Monodelphis dimidiata exhibits a saber-toothed morphology have not been supported by later analyses; Blanco et al, 2013;Chemisquy and Prevosti, 2014).…”

Viral Shedding Evaluation is Critical for Determining Efficacy of Avian Influenza (H9) Vaccines in Broiler Chickens

“…The family diversified substantially in the Miocene and became extinct near the Pliocene (Morlo, 2006), and most of the species are present in the subfamily Barbourofelinae. Barbourofelines are regarded within Nimravidae because both have reduced talonid basin and have tends to be slightly convex, giving the anterior cuspid a slightly inflated morphology of m1 (Wang et al, 2020). According to Barrett et al (2021) the recovered phylogeny implies a migration of nimravine taxa into Africa at MN2, which gave rise to the earliest barbourofelins.…”