The evolution of armadillos, anteaters and sloths depicted by nuclear and mitochondrial phylogenies:: implications for the status of the enigmatic fossil Eurotamandua
The evolution of armadillos, anteaters and sloths depicted by nuclear and mitochondrial phylogenies:: implications for the status of the enigmatic fossil Eurotamandua
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DOI：
10.1098/rspb.2001.1702
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发表时间：
2001-08-07
影响因子：
4.7
通讯作者：
Douzery, EJP
中科院分区：
文献类型：
--
作者：
Delsuc, F;Catzeflis, FM;Douzery, EJP
异种动物目（犰狳、食蚁兽和树懒）是胎盘动物的四个主要分支之一，但从分子系统发育的角度来看，它的研究仍然很少。我们在此提出了一项研究，涵盖了该目的大多数多样性，以建立异人种的内序数关系，讨论其形态特征的演变，寻找其现存的姐妹群，并指定其辐射的时间，特别强调有争议的化石的地位。Eurotamandua。比较了13个活属中8个的3个基因序列（Von Willebrand因子的核外显子28和线粒体12S和16S rnas）。系统发育分析证实了该目的单系性及其三个主要谱系：犰狳（Cingulata），食蚁兽（Vermilingua）和树懒（‘Tardigrada‘，在’Folivora’中更名为‘Folivora’），我们的结果强烈支持将毛茸茸的异种动物（食蚁兽和树懒）归为Pilosa。在胎盘中，非洲兽门可能是第一个分支出来的分支，其次是Xenarthra。证实了新大陆异种穿山甲与旧大陆穿山甲在形态上的适应性趋同。分子年代测定将犰狳的早期出现时间定在白垩纪/第三纪的交界处，随后是始新世早期食蚁兽和树懒的分化。这些第三纪的年代与现代异种人谱系起源非常古老的概念相矛盾。他们还质疑来自欧洲始新世中期的食蚁兽化石（Eurotamandua）与Vermilingua的位置，相反，他们认为这个神秘的分类单元是独立和趋同的进化。
The mammalian order Xenarthra (armadillos, anteaters and sloths) is one of the four major clades of placentals, but it remains poorly studied from the molecular phylogenetics perspective. We present here a study encompassing most of the order's diversity in order to establish xenarthrans' intra-ordinal relationships, discuss the evolution of their morphological characters, search for their extant sister group and specify the timing of their radiation with special emphasis on the status of the controversial fossil. Eurotamandua. Sequences of three genes (nuclear exon 28 of the Von Willebrand factor and mitochondrial 12S and 16S rRNAs) are compared for eight of the 13 living genera. Phylogenetic analyses confirm the order's monophyly and that of its three major lineages: armadillos (Cingulata), anteaters (Vermilingua) and sloths ('Tardigrada', renamed in 'Folivora'), and our results strongly support the grouping of hairy xenarthrans (anteaters and sloths) into Pilosa. Within placentals, Afrotheria might be the first lineage to branch off, followed by Xenarthra. The morphological adaptative convergence between New World xenarthrans and Old World pangolins is confirmed. Molecular datings place the early emergence of armadillos around the Cretaceous/ Tertiary boundary, followed by the divergence between anteaters and sloths in the Early Eocene era. These Tertiary dates contradict the concept of a very ancient origin of modern xenarthran lineages. They also question the placement of the purported fossil anteater (Eurotamandua) from the Middle Eocene period of Europe with the Vermilingua and instead suggest the independent and convergent evolution of this enigmatic taxon.