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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Widanelfarasia, a diminutive placental from the late Eocene of Egypt
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Widanelfarasia, a diminutive placental from the late Eocene of Egypt

机译：Widanelfarasia，来自埃及晚始新世的小胎盘

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摘要

The lower dentition of Widanelfarasia (new genus), a diminutive late Eocene placental from the Fayum Depression in Egypt. is described. Widanelfarasia exhibits a complex of features associ- ated with incipient zalambdodonty and at least three unequivocal apomorphies [loss of P1, an enlarged l2 (relative to l3). and a basal Cusp on l21. which provide weak support for its placement as a possible sister taxon of either a tenrecid--chrysochlorid clade or of solenodontids. The former hypothesis gains additional support from biogeographical evidence. but both scenarios are currently tenuous as Widanelfarasia is clearly not truly zalambdodont. Phylogenetic hypotheses positing affinities with tenrecids alone or chrysochlorids alone must invoke either convergent acquisition of zalambdodonty in these taxa or autapomorphic reversal in Wbonelfarasia. Given these considerations, a relationship with more generalized taxa from the Laurasian Paleogene (e.g., geola- bidids, nyctitheriids. leptictids) cannot yet be ruled out. Compari- sons with other Paleogene Afro-Arabian forms are generally in- conclusive. A relationship with the earlier Eocene Chambtates from Tunisia--currently represented by a single specimen preserv- ing P4M3--seems possible based on the geometry and predicted occlusal relationships of these teeth. but cannot be confidently determined until these two taxa come to be represented by common diagnostic elements. Todralestrs (late Paleocene. Mo- rocco) exhibits general phenetic similarities to Wbonelfarasia, but it is not yet known whether this taxon shares any of Wbonelfara- sia's unequivocal dental apomorphies. Pending the recovery of more informative material. we tentatively refer Wbonelfarasia to Placentalia incert8e sedis. Truly zalambdodont placentals remain conspicuously absent from the Paleogene of Afro-Arabia.
机译：Widanelfarasia（新属）的下牙，这是埃及Fayum凹陷的小型始新世晚期胎盘。描述。 Widanelfarasia表现出复杂的特征，这些特征与初期的ala骨畸形和至少三个明确的异型性有关[P1的丢失，放大了l2（相对于l3）。和21年的基础Cusp这为将其作为触角霉素-金氯化物进化枝或狼牙菌纲的可能姊妹类群的位置提供了薄弱的支持。前一种假设得到了生物地理证据的进一步支持。但目前这两种情况都很脆弱，因为Widanelfarasia显然不是真正的zalambdodont。系统发育假说仅与tenrecid或仅与chchlorsochlorids具有亲和力，因此必须在这些类群中汇聚获得zalambdodonty或在Wbonelfarasia中逆转自交。考虑到这些考虑因素，尚不能排除与劳拉斯古近纪更广义的分类单元的关系（例如，地缘动物，夜蛾科，枯萎病）。与其他古近纪非洲-阿拉伯形式的比较通常是不确定的。与突尼斯较早的始新世斜生齿的关系-目前由单个标本保存P4M3-的标本表示-似乎可能基于这些牙齿的几何形状和咬合关系。但是在这两个分类单元由共同的诊断元素表示之前，无法确定。 Todralestrs（古新世晚期。摩洛哥）与Wbonelfarasia表现出普遍的物候相似性，但尚不知道该分类群是否具有Wbonelfarasia明确的任何亚型。等待恢复更多有用的材料。我们暂时将Wbonelfarasia推荐给incert8e sedis。非裔阿拉伯的古近代确实没有明显的zalambdodont胎盘。

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