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古脊椎动物学报 ›› 2016, Vol. 54 ›› Issue (2): 121-136.

• 古脊椎动物学报 • 上一篇    下一篇

安徽潜山中古新世一新的模鼠兔类

李传夔, 王元青, 张兆群, 毛方园, 孟  津   

  • 出版日期:2016-06-15 发布日期:2016-06-15

A new mimotonidan Mina hui (Mammalia, Glires) from the Middle Paleocene of Qianshan, Anhui, China

LI Chuan-Kui, WANG Yuan-Qing, ZHANG Zhao-Qun, MAO Fang-Yuan, MENG Jin    

  • Published:2016-06-15 Online:2016-06-15

摘要: 命名了中古新世的一个啮型类新属种——胡氏敏兽(Mina hui)。新属种的正型标本为可能属于同一个体的前颌骨和上颌骨,采自安徽省潜山县古井乡傅家山嘴中古新统望虎墩组上段上部。属名来源于周明镇先生的曾用名周敏,以纪念他对我国古新世生物地层和哺乳动物研究的杰出贡献;种名源自胡耀明博士,他为潜山哺乳动物的采集和研究做出过重要贡献。胡氏敏兽的特征如下:中等大小的模鼠兔类,上齿列齿式2∙0∙3∙3; 第一对门齿(dI2)增大,无齿根、终生生长,釉质层双层,仅限于唇侧,表面无纵向浅沟;上颊齿列外缘显著凸出;颧弓前根后缘位于M1–M2之间,眶下孔位置低。以传统的模鼠兔目(Mimotonida)而论,它包括两个科:单型科模鼠兔科(Mimotonidae)只有模鼠兔(Mimotona)一属;模兔科(Mimolagidae)则包括模兔(Mimolagus), Gomphos, Anatolimys, 敏兽和可能的Amar。在已知模鼠兔类中,模鼠兔很可能代表原始的兔形类祖先的“形态型”,而模兔科则代表向兔形类进化的分支上分化出来的旁枝。晓鼠(Heomys)、模鼠兔和敏兽的共存说明啮形类在中古新世时已经分化。 

Abstract: Here we report a new genus and species, Mina hui gen. etsp. nov., of basal Glires from the Middle Paleocene of Qianshan, Anhui, China. The new taxon is characterized by combination of the following characters: medium-sized mimotonidan; upper dental formula 2.0.3.3; dI2 transversely narrow and having smooth labial surface without longitudinal groove; M1 the largest cheek tooth and other cheek teeth decreasing in size considerably away from M1 so that the external margin of the upper cheek tooth row is distinctlyarched labially; lingual side of upper molars unilaterally hypsodont and bearing no hypostria; hypocone being slightly distolingual to protocone; presence of a mesostyle; upper incisor with double-layered enamel structure; posterior border of anterior root of zygoma situated lateral to M1–2 and infraorbital foramen positioned low. M. hui is one of the earliest known Glires, co-existing with Heomys and Mimotonain Qianshan geographically and Middle Paleocene (ca. 61 Ma) chronologically. We consider that the Mimotonida would include two families: the monotypic Mimotonidae that contains Mimotona and Mimolagidae that includes Mimolagus, Gomphos, Anatolimys, Minaand possibly Amar aleator. Among known mimotonidans, Mimotonaprobably represents a primitive “morphotype” as the ancestor of lagomorphs, whereas Mimolagidae includes a side branch diverged from the clade evolved toward lagomorphs. Future research may show that Mimolagidae is not a natural group, and may possibly submerge into Mimotonida, or involve more than one family-level clade. The occurrence of Heomys, Mimotona and Mina from Qianshan show that Glires had already diversified by the Middle Paleocene.