Longchuansmilus xingyongi Jiangzuo & Li & Fu & Duan & Che 2022, SP. NOV.
Creators: name: Jiangzuo, Qigao
name: Li, Shijie
name: Fu, Jiao
name: Duan, Shiqi Wang Xueping Ji Mei
name: Che, Decai
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Carnivora
Felidae
Longchuansmilus

description: LONGCHUANSMILUS XINGYONGI SP. NOV.
(FIGS 3, 4; TABLE 2)
Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: AE047000-2CEB-4B18-9339-38B7AC13C139
Machairodus cf. maximiliani sp. Zong, 1997: 88.
Holotype: YMV87001, a crushed partial cranium, lacking the zygomatic arch, with the poorly preserved basicranial part, from Locality 8603, Zhupeng.
Assigned material: RV2006045 (PDYV1853), a broken upper canine, without tip, from Locality 9907, Leilao; RV2006045 (PDYV702), a broken upper canine, with only the tip, probably from Locality 9803, Xiaohe; PDYV2522.1, an isolated P3, probably from Locality 8801, Xiaohe.
Etymology: The species name is given in honour of Xingyong Zhang, who has contributed greatly to the discovery and study of the fossils at the Yuanmou hominid site.
Type locality: Yuanmou.
Diagnosis: Medium-sized machairodontine of large jaguar size. Forehead not distinctly wider than rostrum, but frontal sinus well developed. Incisor moderate in size, not procumbent; canine narrow, with clear serration; no P2; P3 reduced in size, with distinct anterior accessory cusp; P4 with distinct preparastyle and moderately reduced protocone.
Differential diagnosis: Differs from Machairodus by its smaller size, I2 with V-shaped posterior accessory cusp, more reduced P3 and P4 protocones; differs from Amphimachairodus by its distinctly smaller size, smaller and less procumbent incisor, more reduced P3; differs from Lokotunjailurus by smaller size, absence of P2, slightly larger P3, less elongated P4 with larger protocone; differs from Homotherium / Xenosmilus by its smaller size, distinctly smaller and much less procumbent incisor, larger P3 and P4 protocones,
stronger P4 parastyle; differs from Paramachaerodus and Metailurus by its larger size, presence of distinct canine serration, smaller P3 and distinctly stronger P4 preparastyle and smaller protocone.
Description
The cranium is nearly complete, but unfortunately laterally crushed and somewhat deformed. The zygomatic arch is missing and poorly reconstructed by plaster. The posterior part of the sagittal crest is broken (so the total length of the skull cannot be established) and the basicranial part is poorly preserved.
The cranium seems to have an angle in its dorsal profile, at the level of the anterior part of the braincase. In dorsal view, it can be seen that the rostrum has no postcanine constriction. No information on nasal shape and its boundary can be extracted due to poor preservation. The postorbital process of the frontal is small but distinct. The forehead is not widened, only slightly wider than the rostrum. It can be seen that the frontal sinus is well developed, expanding the postorbital constriction. The temporal ridges from both sides unite with the sagittal crest at the level between the postorbital constriction and the braincase. The sagittal crest is well developed. In lateral view, the mastoid process is largely broken, but judging from the remaining part, the mastoid process is significantly enlarged. There is nearly no trait that can be seen in the ventral view due to breakage. The bony choana extends significantly posterior to the tooth row. The glenoid fossa does not seem to elevate above the basicranial region.
The incisor row is only slightly procumbent. The medial incisor is slightly enlarged. Judging from the facet, the posterior accessory cusps are V-shaped and ridge-like. The I3 is slightly enlarged, without an accessory cusp. The canine is narrow, with clear serration seen in the posterior side. (The situation in the anterior side is invisible) There is no P2. The P3 is reduced in size. It has a distinct anterior accessory cusp, located slightly medial to the main cusp. The lingual part of the tooth cannot be clearly seen due to poor preservation. The buccal border is concave between the main cusp and the posterior cingulum. The P4 has a narrow blade. The parastyle part is clearly elongated. Even though the tooth is heavily worn, it can be seen that the preparastyle is large and seems to be in line with the parastyle. The metacone is also elongated. The protocone is reduced in size. It is located at the level between the parastyle and paracone.
There were two isolated canine fragments and one P3 that most likely belongs to this species. Both canine fragments have clear serrations on their edges. The P3 is in good preservation; it is nearly the same size as that of YMV87001 and has a similar tooth outline. The anterior accessory cusp is more lingually located than in the case of YMV87001. The postero-lingual convexity is distinct. The posterior cingulum has a distinct cusp. A single premolar RV2006046, which seems to be a p3, has a unique morphology. Weak serration can be seen in the tooth, a typical trait of Machairodontini, and seems to be too small for Amphimachairodus, which we tentatively assign to Longchuansmilus.
description: Published as part of Jiangzuo, Qigao, Li, Shijie, Fu, Jiao, Duan, Shiqi Wang Xueping Ji Mei & Che, Decai, 2022, Fossil Felidae (Carnivora: Mammalia) from the Yuanmou hominid site, southern China (Late Miocene) and its significance in the living environment of the fossil ape, pp. 1156-1174 in Zoological Journal of the Linnean Society 196 on pages 1159-1161, DOI: 10.1093/zoolinnean/zlab116, http://zenodo.org/record/7323717