A Unique Late Triassic Dinosauromorph Assemblage Reveals Dinosaur Ancestral Anatomy and Diet
A Unique Late Triassic Dinosauromorph Assemblage Reveals Dinosaur Ancestral Anatomy and Diet
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DOI：
10.1016/j.cub.2016.09.040
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发表时间：
2016-11-21
期刊：
影响因子：
9.2
通讯作者：
Langer, Max Cardoso
中科院分区：
文献类型：
--
作者：
Cabreira, Sergio Furtado;Armin Kellner, Alexander Wilhelm;Langer, Max Cardoso
恐龙形类包括恐龙和其他种类较少的三叠纪恐龙的祖先，如兔形目[1]。这些分类群与恐龙的联合出现是罕见的，但在那个时期的最后一部分（Norian-Rhaetian，2.28 - 2.01亿年前[mya]）更常见[2，3]。相比之下，这里描述的新的拉格佩迪和蜥脚类恐龙是从世界上最古老的恐龙化石岩石单位之一，巴西南部的卡尼（237-228百万年）圣玛利亚组中出土的[4]，这一记录只有来自阿根廷的更零碎的遗骸在年龄上匹配[5]。这是第一次在同一次挖掘中同时发现几乎完整的恐龙和非恐龙化石，清楚地表明这些动物是恐龙进化第一阶段以来的同时代人。新的Lagerpetid保存了第一个头骨，肩胛骨和前肢元素，以及相关的椎骨，以该群体而闻名，揭示了恐龙如何获得几个典型的解剖特征。此外，一项新的系统发育分析显示，新恐龙是最基本的蜥脚类。它的类形牙齿，严格适应动物群，提供了重要的数据来推断第一批恐龙的进食行为。
Dinosauromorpha includes dinosaurs and other much less diverse dinosaur precursors of Triassic age, such as lagerpetids [1]. Joint occurrences of these taxa with dinosaurs are rare but more common during the latest part of that period (Norian-Rhaetian, 228-201 million years ago [mya]) [2, 3]. In contrast, the new lagerpetid and saurischian dinosaur described here were unearthed from one of the oldest rock units with dinosaur fossils worldwide, the Carnian (237-228 mya) Santa Maria Formation of south Brazil [4], a record only matched in age by much more fragmentary remains from Argentina [5]. This is the first time nearly complete dinosaur and non-dinosaur dinosauromorph remains are found together in the same excavation, clearly showing that these animals were contemporaries since the first stages of dinosaur evolution. The new lagerpetid preserves the first skull, scapular and forelimb elements, plus associated vertebrae, known for the group, revealing how dinosaurs acquired several of their typical anatomical traits. Furthermore, a novel phylogenetic analysis shows the new dinosaur as the most basal Sauropodomorpha. Its plesiomorphic teeth, strictly adapted to faunivory, provide crucial data to infer the feeding behavior of the first dinosaurs.