NEW REMAINS OF EOCENE AND OLIGOCENE AFROSORICIDA (AFROTHERIA) FROM EGYPT, WITH IMPLICATIONS FOR THE ORIGIN(S) OF AFROSORICID ZALAMBDODONTY
NEW REMAINS OF EOCENE AND OLIGOCENE AFROSORICIDA (AFROTHERIA) FROM EGYPT, WITH IMPLICATIONS FOR THE ORIGIN(S) OF AFROSORICID ZALAMBDODONTY
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来自埃及的始新世和渐新世 Afrothericida (AFROTHERIA) 新遗迹，对 AFROSORICID ZALAMBDODONTY 的起源有影响
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
Y. Attia
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作者：
E. Seiffert;E. Simons;T. Ryan;T. Bown;Y. Attia
金龟科(金鼹科)和金龟科(Tenrecae)的分化可以追溯到K-T界线附近，但目前这些分支中最古老的化石成员是中新世早期(∼20 Ma)。唯一被认为可能是茎类的非洲属是埃及的晚始新世(∼34 Ma)Widanelfarasia，到目前为止只知道下牙列。在这里，我们使用高分辨率计算机断层扫描来显示Widanelfarasia的上颌后犬齿的形态，并描述了早渐新世Jawharia(Gen.11月)和Eochrysoloris(Gen.)11月)。Widanelfarasia的上磨牙牙列提供了介于中度双齿和早期Zalambdodon之间的中间形态阶段的证据。利用Asher和Hofreiter(2006)的形态特征矩阵进行的系统发育分析将Widanelfarasia归入树冠总科，但不能从统计上拒绝将该属作为茎类目的替代位置。Eochrysoloris gen提供了对后一种假说和无翅目内Zalambdodonty会聚进化假说的额外支持。Nov.，它与中新世原金线虫和现存的金绿藻类具有相似的前磨牙特征，但在其下臼齿上保留了发育良好的塔龙盆地。Jawharia Gen.11月被解释为一种高级的茎Tenrecid，这为Tenrecid zalambdodonty是从适度的双齿进化而来的假说提供了额外的支持。Widanelfarasia和早中新世Protenrec共有的一些无形性形态特征也在Todralestes中看到，Todralestes来自非洲最古老(晚古新世)的胎盘哺乳动物产区。因此，Todralestes可能是一种茎或树冠，如果是这样的话，就是Afotheria中已知的最古老的非裔阿拉伯成员。
Abstract Molecular estimates for the divergence of Chrysochloridae (golden moles) and Tenrecoidea (tenrecs) date back to near the K-T boundary, but at present the oldest undoubted fossil members of these clades are early Miocene in age (∼20 Ma). The only Paleogene African genus that has been proposed as a possible stem tenrecoid is late Eocene (∼34 Ma) Widanelfarasia from Egypt, heretofore known only from the lower dentition. Here we employ high-resolution computed tomography to reveal the morphology of the maxillary post-canine dentition of Widanelfarasia, and describe fragmentary dental and mandibular remains of early Oligocene Jawharia (gen. nov.) and Eochrysochloris (gen. nov.). The upper molar dentition of Widanelfarasia provides evidence for an intermediate morphological stage between moderate dilambdodonty and incipient zalambdodonty. Phylogenetic analysis employing the morphological character matrix of Asher and Hofreiter (2006) places Widanelfarasia within crown Tenrecoidea, but an alternative placement of that genus as a stem tenrecoid could not be statistically rejected. Additional support for the latter hypothesis, and for the hypothesis of convergent evolution of zalambdodonty within Afrosoricida, is provided by Eochrysochloris gen. nov., which shares apomorphic premolar features with Miocene Prochrysochloris and extant chrysochlorids, but retains a well-developed talonid basin on its lower molars. Jawharia gen. nov. is interpreted as an advanced stem tenrecoid that provides additional support for the hypothesis that tenrecoid zalambdodonty evolved from moderate dilambdodonty. Some of the apomorphic morphological features shared by Widanelfarasia and early Miocene Protenrec are also seen in Todralestes, from the oldest (late Paleocene) placental mammal-bearing locality in Africa. As such Todralestes may be a stem or crown afrosoricid, and, if so, the oldest known Afro-Arabian member of Afrotheria.