Hyaenodonta is a diverse, extinct group of carnivorous mammals that included weasel- to rhinoceros-sized species. The oldest-known hyaenodont fossils are from the middle Paleocene of North Africa and the antiquity of the group in Afro-Arabia led to the hypothesis that it originated there and dispersed to Asia, Europe, and North America. Here we describe two new hyaenodont species based on the oldest hyaenodont cranial specimens known from Afro-Arabia. The material was collected from the latest Eocene Locality 41 (L-41, ∼34 Ma) in the Fayum Depression, Egypt. Akhnatenavus nefertiticyon sp. nov. has specialized, hypercarnivorous molars and an elongate cranial vault. In A. nefertiticyon the tallest, piercing cusp on M1-M2 is the paracone. Brychotherium ephalmos gen. et sp. nov. has more generalized molars that retain the metacone and complex talonids. In B. ephalmos the tallest, piercing cusp on M1-M2 is the metacone. We incorporate this new material into a series of phylogenetic analyses using a character-taxon matrix that includes novel dental, cranial, and postcranial characters, and samples extensively from the global record of the group. The phylogenetic analysis includes the first application of Bayesian methods to hyaenodont relationships. B. ephalmos is consistently placed within Teratodontinae, an Afro-Arabian clade with several generalist and hypercarnivorous forms, and Akhnatenavus is consistently recovered in Hyainailourinae as part of an Afro-Arabian radiation. The phylogenetic results suggest that hypercarnivory evolved independently three times within Hyaenodonta: in Teratodontinae, in Hyainailourinae, and in Hyaenodontinae. Teratodontines are consistently placed in a close relationship with Hyainailouridae (Hyainailourinae + Apterodontinae) to the exclusion of "proviverrines," hyaenodontines, and several North American clades, and we propose that the superfamily Hyainailouroidea be used to describe this relationship. Using the topologies recovered from each phylogenetic method, we reconstructed the biogeographic history of Hyaenodonta using parsimony optimization (PO), likelihood optimization (LO), and Bayesian Binary Markov chain Monte Carlo (MCMC) to examine support for the Afro-Arabian origin of Hyaenodonta. Across all analyses, we found that Hyaenodonta most likely originated in Europe, rather than Afro-Arabia. The clade is estimated by tip-dating analysis to have undergone a rapid radiation in the Late Cretaceous and Paleocene; a radiation currently not documented by fossil evidence. During the Paleocene, lineages are reconstructed as dispersing to Asia, Afro-Arabia, and North America. The place of origin of Hyainailouroidea is likely Afro-Arabia according to the Bayesian topologies but it is ambiguous using parsimony. All topologies support the constituent clades-Hyainailourinae, Apterodontinae, and Teratodontinae-as Afro-Arabian and tip-dating estimates that each clade is established in Afro-Arabia by the middle Eocene.

译文

斑牙don属是食肉性哺乳动物的一种不同的,灭绝的群体,其中包括黄鼠狼到犀牛大小的物种。最著名的透明牙齿化石来自北非中古新世,该集团在非洲-阿拉伯的上古时期导致了这一假说起源于该地区并散布到亚洲,欧洲和北美。在这里,我们根据从非洲-阿拉伯共和国已知的最古老的鬣狗颅骨标本描述两种新的鬣狗牙种。该材料是从埃及Fayum凹陷最新的始新世地方41(L-41,约34 Ma)收集的。 Akhnatenavus nefertiticyon sp。十一月有专门的,食肉性高的臼齿和细长的颅骨穹顶。在A. nefertiticyon中,M1-M2上最高的,刺穿的尖尖是对位圆锥形。 Brychotherium ephalmos gen。等十一月具有更广泛的臼齿,保留了前锥体和复杂的距骨。在麻疯树(B. ephalmos)中,M1-M2上最高的,刺穿的尖头是元圆锥。我们使用字符分类单元矩阵将这种新材料纳入一系列的系统发育分析中,该矩阵包括新颖的牙齿,颅骨和颅后字符,并从该小组的全球记录中广泛获取样本。系统发育分析包括将贝叶斯方法首次应用于透明牙齿关系。依法将B. ephalmos始终放置在Teratodontinae(一种具有多种通体和肉食性形式的非裔阿拉伯进化枝)中,并且Akhnatenavus一直在Hyainailourinae中作为非裔阿拉伯辐射的一部分被回收。系统发育结果表明,高食肉动物在斑牙齿independently内独立进化了三次:在畸齿龙齿科,Hyainailourinae和斑牙齿tina科。畸齿动物一直与Hyainailouridae(Hyainailourinae Apterodontinae)保持密切的关系,但排除了“ proverrrines”,hyenenodontines和一些北美进化枝,我们建议使用超家族Hyainailouroidea来描述这种关系。使用从每种系统发育方法中恢复的拓扑,我们使用简约优化(PO),似然性优化(LO)和贝叶斯二进制马尔可夫链蒙特卡洛(MCMC)重建了斑纹齿bio的生物地理历史,以检验对斑纹齿f的非洲阿拉伯起源的支持。在所有分析中,我们都发现了斑纹牙most很可能起源于欧洲,而不是非洲-阿拉伯。通过尖端日期分析估计该进化枝在白垩纪晚期和古新世经历了快速辐射。目前没有化石证据记录的辐射。在古新世期间,世系被重建并扩散到亚洲,非洲-阿拉伯和北美。根据贝叶斯拓扑,Hynailnailoidoidea的产地可能是非洲-阿拉伯,但使用简约法则是模棱两可的。所有拓扑都支持组成类进化支-Hyainailourinae,Apterodontinae和Teratodontinae-非洲裔阿拉伯人,据先验估计,每个进化枝都是在中新世中期在非洲裔阿拉伯人中建立的。

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