Morphology through ontogeny of Chinese Proboscidipparion and Plesiohipparion and observations on their Eurasian and African relatives

分析了来自贺风近三趾马(Plesiohipparion houfenense)、原始长鼻三趾马(Proboscidipparion pater)和中国长鼻三趾马(Proboscidipparion sinense)三个种的共计18颗经过切片处理的颊齿,总结了颊齿在个体发育过程中的形态变化,并揭示出这些中国类群与其他欧亚大陆以及非洲的三趾马门类之间可能存在近裔共征。在形态特征上,Pl.houfenense的上下颊齿很可能与西班牙的Pl.crusafonti,土耳其的Plesiohipparion aff.P.huangheense以及非洲的Eurygnathohippus类群有共同特征。另一方面,这些欧亚大陆和非洲类群事实上很可能起源于西瓦利克的Sivalhippus类群。Proboscidipparion属中的两个种,P.pater和P.sinense之间有着明显的亲缘关系,并且可能与土耳其的'Proboscidipparion'heintzi也有亲缘关系。另外,以前的学者曾提出Proboscidipparion与Sivalhippus支系存在亲缘关系,本文对P.pater和P.sinense上、下颊齿的分析支持了这一观点。

We analyse and figure a total of 18 sectioned cheek teeth of Plesiohipparion houfenense, Proboscidipparion pater and Proboscidipparion sinense to digitally document and characterize the morphologic changes through their ontology and to discover possible synapomorphies between these Chinese taxa and other Eurasian and African hipparion lineages. The maxillary and mandibular cheek teeth ofP houfenense are found to likely share characters in common with Spanish Plesiohipparion crusafonti, Turkish Plesiohipparion aft. P huangheense and the African Eurygnathohippus lineage. In turn, these Eurasian and African lineages may in fact have their evolutionary roots in the Siwalik Sivalhippus lineage. The two Proboscidipparion species, P. pater and P sinense are clearly related to each other, and likely related to Turkish ＂Proboscidipparion＂ heintzi. Likewise, our analysis of P pater and P sinense maxillary and mandibular cheek teeth support this genus＇ relationships with the Plesiohipparion and Sivalhippus clades previous argued by other authors.