A NEW BASAL ARCHOSAURIFORM DIAPSID FROM THE LOWER TRIASSIC OF ARGENTINA
A NEW BASAL ARCHOSAURIFORM DIAPSID FROM THE LOWER TRIASSIC OF ARGENTINA
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DOI：
10.1080/02724634.2010.501446
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发表时间：
2010-01-01
影响因子：
1.4
通讯作者：
Martinelli, Agustin
中科院分区：
文献类型：
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作者：
Ezcurra, Martin D.;Lecuona, Agustina;Martinelli, Agustin
最著名的南美早三叠世主龙类属于何塞·波拿巴 (Jose Bonaparte) 于 1981 年简要报道的假定原鳄科，采集自 Quebrada de los Fosiles 地层（阿根廷 Puesto Viejo 群）。该标本由保存完好的部分颅骨后部天然外部模具组成，其中保存有背椎骨、皮骨、背侧肋骨、可能的胃骨、V 形骨、肱骨、髂骨、两个后足和一个爪子。我们重新描述了这个标本，并确定了自体变异，使我们能够识别柯伊拉马鳄（Koilamasuchus gonzalezdiazi），gen。等十一月由于髂骨叶片的背缘稍凸，且最大长度超过其最大高度的 3 倍，因此柯伊拉马鳄属于祖龙形目。对基础主龙形目的分支分析表明，柯拉马鳄比原鳄鳄、萨尔马托鳄、河豚鳄和 Osmolskina 更靠前，是包括红鳄科和主龙亚目在内的分支的姐妹分类单元。发现原鳄科是并系的。髂前髋臼突、与髂骨纵轴形成小于 45 度角的耻骨脚以及背体骨皮的存在，使得主龙形目中的柯拉马鳄比原鳄科更靠冠。柯拉马鳄在主龙形目中比红鳄科更基础，因为背侧肋骨的近端发育不良。柯拉马鳄在二叠纪-三叠纪大规模灭绝后的生物恢复过程中显着增加了主龙形目的多样性。
The best-known South American Early Triassic archosauriform belongs to a putative proterosuchid briefly reported by Jose Bonaparte in 1981, collected from the Quebrada de los Fosiles Formation (Puesto Viejo Group, Argentina). This specimen consists of well-preserved natural external molds of a partial postcranium that preserve dorsal vertebrae, osteoderms, a dorsal rib, a possible gastralium, a chevron, a humerus, an ilium, two metapodials, and an ungual. We re-describe this specimen and identify autapomorphies that allow us to recognize Koilamasuchus gonzalezdiazi, gen. et sp. nov. The presence of an iliac blade with a slightly convex dorsal margin and with a maximum length more than 3 times its maximum height places Koilamasuchus within Archosauriformes. A cladistic analysis of basal Archosauriformes positions Koilamasuchus more crownwards than Proterosuchus, Sarmatosuchus, Fugusuchus, and Osmolskina, as the sister taxon of the clade that includes Erythrosuchidae and Archosauria. Proterosuchidae is found to be paraphyletic. The presence of an iliac preacetabular process, a pubic peduncle that forms an angle lower than 45 degrees to the longitudinal axis of the ilium, and dorsal body osteoderms positions Koilamasuchus in Archosauriformes more crownwards than proterosuchids. Koilamasuchus is more basal than erythrosuchids within Archosauriformes because of the presence of dorsal ribs with a poorly developed proximal end. Koilamasuchus importantly increases the diversity of Archosauriformes during the biotic recovery following the Permo-Triassic mass extinction.