Mosaicomeryx gen. nov., a ruminant mammal from the Oligocene of Europe and the significance of ‘gelocids’

The description of new material and the reassessment of specimens previously assigned to Gelocus quercyi lead us to propose a new genus for this species, Mosaicomeryx gen. nov. Moreover, the description of a juvenile skull and other specimens of Prodremotherium elongatum, and comparison with Dremotherium, provide evidence that these two genera are not closely related as previously thought. A phylogenetic analysis based on 40 dental, cranial and postcranial features highlights the misidentification of Gelocus quercyi and suggests that Mosaicomeryx gen. nov. is closely related to Prodremotherium elongatum. Mosaicomeryx quercyi and Prodremotherium elongatum form a monophyletic group of stem Pecora that first appeared in Western Europe by the late Early Oligocene (MP25–26), and Prodremotherium elongatum persisted up to MP28; following this time both taxa appear to be replaced by Dremotherium and Amphitragulus. This time interval covers two major Oligocene faunal and climate changes: Extinction 1 (MP24), associated with regression of the inner European sea, and Extinction 3/Migrations 3 (MP28), associated with Late Oligocene Warming.http://zoobank.org/urn:lsid:zoobank.org:pub:CC044612-B707-4CCD-B121-0830DA304396

针对此前被归入栎色凝胶鹿（Gelocus quercyi）的标本所开展的新材料描述与重新评估，促使我们为该物种建立新属——镶嵌鹿属（Mosaicomeryx gen. nov.）。此外，通过对长身前始鹿（Prodremotherium elongatum）的幼年颅骨标本及其他相关标本的描述，并与始鹿属（Dremotherium）进行对比分析，本研究证实这两个属的亲缘关系并不如既往研究所认为的那般紧密。基于40项牙齿、颅骨及颅后骨骼特征开展的系统发育分析，不仅揭示了栎色凝胶鹿的分类鉴定存在误判，同时表明镶嵌鹿属与长身前始鹿的亲缘关系极为密切。栎色镶嵌鹿（Mosaicomeryx quercyi）与长身前始鹿共同构成基干反刍类（Pecora）的单系群，该类群最早于早渐新世晚期（MP25–26）出现在西欧地区，且长身前始鹿的存续时限直至MP28；在此时间节点之后，这两个类群似乎均被始鹿属与两栖鹿属（Amphitragulus）所取代。该时间间隔涵盖了两次重大的渐新世动物群与气候转型事件：与欧洲内海退缩相关的绝灭事件1（MP24），以及与晚渐新世增温相关的绝灭事件3/迁移事件3（MP28）。http://zoobank.org/urn:lsid:zoobank.org:pub:CC044612-B707-4CCD-B121-0830DA304396