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Chinese Machairodontinae (Carnivora, Felidae) and their ecological significance

2020; Science China Press; Volume: 66; Issue: 12 Linguagem: Inglês

10.1360/tb-2020-1164

2095-9419

Yu Li, Wenhui Liu, Lihua Wang,

Wildlife Ecology and Conservation

Being a common element in late Cenozoic mammalian faunas, saber-toothed felids (or machairodonts) are of important significance for biostratigraphic inferences and paleoecological reconstructions. Late Cenozoic strata in China have produced abundant fossils of saber-toothed felids, including typical forms with extremely elongated and compressed upper canine and very specialized jaw joint structure, such as Machairodus , Megantereon , Homotherium , as well as some intermediate forms which morphology lies between Felinae and Machairodontinae, such as Paramachaerodus , Metailurus , Dinofelis . Our review suggest that there were at least 13 species of 6 genera of Machairodontinae existed in China, including: Machairodus horribilis , Ma. palanderi , Homotherium crenatidens , H. ultimum , Paramachaerodus transasiaticus , Par. maximiliani , Megantereon megantereon , Meg. nihowanensis , Meg. inexpectatus , Metailurus major , Met. ultimus , Met. hengduanshanensis and Dinofelis cristata. Ma. horribilis and Ma. palanderi are two advanced forms of this genus that stand the same broad evolutionary stage with European species Ma. giganteus . Compared with Ma. giganteus , Ma. horribilis is larger in size with broader end of mastoid process and less reduced paraoccipital process, it has a two-rooted P2, its p3 and p4 develop additional cuspids. While, Ma. palanderi is smaller in size, also preserves P2, its p3 is more retracted with more reduced mesial cuspid, the metaconid-talonid complex is also more reduced. For the two pleistocene species of Homotherium , the younger age H. ultimum is more advanced than H. crenatidens , it has extremely reduced p3, elongated and more blade-like p4 with high and posteriorly tilted cuspids and P4 without any trace of protocone. Par. maximiliani is the most advanced forms of this genus, compared with other earlier aged forms, it has a more elongated and blade-like P4 with well-developed ectostyle and smaller protocone, the talonid of m1 is extremely reduced. Compared to Meg. megantereon , Meg. nihowanensis shows relatively more derived traits, as the p3 and the protocone of P4 is more reduced, the mastoid process and postglenoid process protruding more ventrally, covering the auditory bulla in lateral view. The specialized P4 with extremely reduced protocone shows that Meg. inexpextatus is a more advanced form than the other two, which also found in younger deposits. A well-preserved skull from Nihowan Basin confirms that the species D. abeli establied based on specimens from Mianchi, Henan Province should be treated as a synonym of Siwalik species D. cristata , this species shows the most Panthera -like features in the genus. Furthermore, we examined phylogenetic studies focused on Machairodontinae, especially those including highly controversial intermediate forms, and made some comments on them. Combining the mammal fauna of different sites in China, we briefly discussed the paleoecology of relevant groups, and inferred their preferred habitat and prey groups. The niche of Ma. horribilis was probably similar to that of the extant tiger, which mainly preys on medium to large ungulates. The niches of Paramachaerodus and Megantereon are found to be similar to that of the extant jaguar. The former fossil form mainly feeds on small to medium-sized herbivores, while the latter is more likely to handle larger ones. The three fossil groups mentioned above mainly lived in woodland environment. The niches of Ma. palanderi and Homotherium were probably similar to that of the lion, which mainly preys on medium to large ungulates. In contrast, the niche of Metailurus was close to that of the leopard, which prefers to hunt preys of similar or slightly larger size than itself. These three taxa mainly live in more open areas than woodlands. The preferred habitat of Dinofelis cristata is still unknown, but its hunting habits may be similar to that of extant lions or tigers.