Morphology, relationships, and biogeographical significance of an extinct horned crocodile (Crocodylia, Crocodylidae) from the Quaternary of Madagascar
Morphology, relationships, and biogeographical significance of an extinct horned crocodile (Crocodylia, Crocodylidae) from the Quaternary of Madagascar
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DOI：
10.1111/j.1096-3642.2007.00315.x
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发表时间：
2007-08-01
影响因子：
2.8
通讯作者：
Brochu, Christopher A.
中科院分区：
文献类型：
--
作者：
Brochu, Christopher A.
系统发育分析表明，粗壮鳄鱼（Crocodylus robustus Grandidier & Vaillant，1872）与现存的非洲矮鳄（Osteolaemus）的关系比现存的鳄鱼更密切。模式系列无法确定，但原始描述包括与已知标本一致的细节，几乎可以肯定属于同一物种。它有一个突出的三角形的“角”上的后外侧角的每个鳞片;近排斥的鼻骨从外部鼻孔;收缩的上颞窗边缘;背腹深吻;收缩的外部下颌窗，其中surangular-angular缝出现在后方，而不是posteroventral边缘;和强大的肢体和肢体带元素。它与骨龙属（Osteolaemus）和几种已灭绝的来自非洲新近纪的鳄鱼科（Crocodylids）一样，在内部后鼻孔周围的翼状骨表面凹陷，形成后鼻孔“颈”。它不能被称为Crocodylus和一个新的首名，Vbay，是建立其接待。Vbay一直持续到全新世，可能在2000年前人类首次定居马达加斯加时已经存在，当时它可能是岛上巨型动物灭绝事件的受害者。这是一致的分子数据表明，最近的传播鳄鱼尼罗从非洲大陆到马达加斯加。(c)2007年，伦敦林奈学会。
Phylogenetic analysis indicates that Crocodylus robustus Grandidier & Vaillant, 1872 is more closely related to the living African dwarf crocodiles (Osteolaemus) than to living Crocodylus. The type series cannot be identified, but the original description includes details consistent with known specimens that almost certainly pertain to the same species. It had a prominent triangular 'horn' on the posterolateral corner of each squamosal; near-exclusion of the nasals from the external naris; constricted supratemporal fenestral rims; a dorsoventrally deep snout; a constricted external mandibular fenestra in which the surangular-angular suture emerges from the posterior rather than posteroventral margin; and robust limb and limb girdle elements. It shares with Osteolaemus, and with several extinct crocodylids from the Neogene of Africa, a depressed surface of the pterygoid around the internal choana forming a choanal 'neck'. It cannot be referred to Crocodylus and a new praenomen, Vbay, is established for its reception. Vbay persisted into the Holocene and may have been extant when humans first settled Madagascar 2000 years ago, when it may have been a casualty of a megafaunal extinction event on the island. This is consistent with molecular data that suggest comparatively recent dispersal of Crocodylus niloticus to Madagascar from mainland Africa. (c) 2007 The Linnean Society of London.