Amphimachairodus hezhengensis, Jiangzuo & Werdelin & Sanisidro & Yang & Fu & Li & Wang & Deng, 2023

Jiangzuo, Qigao, Werdelin, Lars, Sanisidro, Oscar, Yang, Rong, Fu, Jiao, Li, Shijie, Wang, Shiqi & Deng, Tao, 2023, Origin of adaptations to open environments and social behaviour in sabretoothed cats from the northeastern border of the Tibetan Plateau, Proceedings of the Royal Society B: Biological Sciences (20230019) 290 (1997), pp. 1-11 : 1992

Amphimachairodus hezhengensis sp. nov.

Machairodus palanderi p.257, Deng et al. 2013

Amphimachairodus sp. p.11 Jiangzuo et al. 2023

Holotype: HMV2041 , a nearly complete cranium ( figure 1 ; electronic supplemenatry material, figures S1 and S2) .

Etymology: After the place (Hezheng Paleozoological Museum, Hezheng, China) where the specimen was found and is currently stored.

Type locality: Houshan, Linxia Basin , Gansu province of northern China.

Chronology and distribution: Thus far only known from the early Late Miocene of northern China.

Diagnosis: medium-sized Amphimachairodus with small incisors and I1 with lingually posited accessory cusps; long C-P3 diastema; presence of P2; relatively small cheek teeth; small P4 preparastyle and moderate protocone.

Differential diagnosis: differs from Machairodus and Nimraoides in having different cranial morphology, e.g. lower angle between facial and neurocranial part, wide forehead, retracted orbit and long rostrum, shorter and dorsally arched zygomatic arch, slightly overhanging glenoid fossa, more arched incisor row and more separated lingual accessory cusps in I2, presence of P2, more distinct P4 preparastyle and smaller protocone; differs from Lokotunjailurus in having larger size, longer C-P3 diastema, stronger P3 anterior accessory cusp and more robust P4; differs from other species of Amphimachairodus in having smaller incisors, I1 with two closely located lingual accessory cusps, longer C-P3 diastema, smaller cheek teeth, smaller P4 preparastyle and slightly larger protocone.

Figures

Figure 1. (a) Cranium of Amphimachairodus hezhengensis sp. nov. HMV2041. a1, dorsal view; a2, anterior view; a3, ventral view; a4, postero-ventral view; a5, lateral view. (b) Geography of fossil locality. (c) Pathology of the MC2 and MC3 of Amphimachairodus sp. HMV2047 forepaw. (d) Large predator contemporary with A. hezhengensis in the Linxia Basin. d1, A. hezhengensis, HMV2041; d2, Dinocrocuta gigantea, HMV2044; d3, Agriotheriini ursid, HMV2046.