Data from: The European Paromomyidae (Primates, Mammalia): taxonomy, phylogeny, and biogeographic implications

Plesiadapiforms represent the first radiation of Primates, appearing near the Cretaceous-Paleogene boundary. Eleven families of plesiadapiforms are recognized, including the Paromomyidae. Four species of paromomyids from the early Eocene have been reported from Europe: Arcius fuscus, Arcius lapparenti, and Arcius rougieri from France, and Arcius zbyszewskii from Portugal. Other Arcius specimens from the early Eocene are known from Masia de l’Hereuet (Spain), Abbey Wood (England), and Sotteville-sur-Mer (Normandy, France). A cladistic analysis of the European paromomyids has never previously been published. A total of 53 dental characters were analyzed for the four Arcius species and the specimens from Spain, England, and Normandy. The results of a parsimony analysis using TNT agree with previous conceptions of A. zbyszewskii as the most primitive member of the genus. Also consistent with existing hypotheses, Arcius rougieri is positioned as the sister taxon of A. fuscus and A. lapparenti, and the results suggest that the fossil from Normandy is A. zbyszewskii. However, the English fossil pertains to a primitive lineage, rather than grouping with A. lapparenti as had been suggested; as such it is recognized here as a distinct species (Arcius hookeri). The Spanish fossils cluster together with the French species, but do not show the previously proposed special relationship with A. lapparenti, and are sufficiently distinct to be placed in a new species (Arcius ilerdensis). Arcius is recovered as monophyletic, which is consistent with a single migration event from North America to Europe around the earliest Eocene though the Greenland land bridge.

更猴形类（Plesiadapiforms）代表了灵长目（Primates）的首次辐射演化（radiation），其出现时间紧邻白垩纪-古近纪界线。目前已被确认的更猴形类共计11个科，其中包含拟猴科（Paromomyidae）。产自欧洲始新世早期的拟猴科物种目前已有4种被正式报道：分别为发现于法国的Arcius fuscus、Arcius lapparenti与Arcius rougieri，以及发现于葡萄牙的Arcius zbyszewskii。另有产自欧洲始新世早期的Arcius属标本，分别发现于西班牙的Masia de l’Hereuet、英国的Abbey Wood以及法国诺曼底的Sotteville-sur-Mer。此前尚未有针对欧洲拟猴科的分支分类学分析（cladistic analysis）研究公开发表。本次研究共针对4种Arcius属物种以及上述西班牙、英国、诺曼底地区的标本，分析了共计53个牙齿特征（dental characters）。基于TNT软件开展的简约分析（parsimony analysis）结果显示，Arcius zbyszewskii作为该属最原始物种的观点与此前的研究结论一致。同时，研究结果也支持现有假说：Arcius rougieri是Arcius fuscus与Arcius lapparenti的姊妹群（sister taxon），且推断诺曼底地区的化石标本隶属于Arcius zbyszewskii。但英国的化石标本并未像此前推测的那样归入Arcius lapparenti类群，而是隶属于一个更为原始的演化支系（lineage），因此本次研究将其认定为一个独立物种（Arcius hookeri）。西班牙的化石标本与法国物种聚为一支，但并未表现出此前提出的与Arcius lapparenti的特殊亲缘关系，且二者的形态差异足够显著，因此将其归入新种（Arcius ilerdensis）。系统发育分析结果显示Arcius属为单系群（monophyletic），这与"在始新世早期通过格陵兰陆桥发生过一次从北美向欧洲的迁移事件"的假说相符。