Delcourt Rafael
Department of Zoology,Trinity College Dublin, Dublin, Ireland.
Zootaxa. 2017 Jun 9;4276(1):1-45. doi: 10.11646/zootaxa.4276.1.1.
Abelisaurid theropods were most abundant in the Gondwana during the Cretaceous Period. Pycnonemosaurus nevesi Kellner & Campos, 2002 was the first abelisaurid dinosaur described from the Bauru Group (Brazil, Upper Cretaceous). Nevertheless, its initial description was based on the comparison of a restricted number of remains with other abelisaurids. In this paper, I present a new description of the morphology of Pycnonemosaurus nevesi, including three new caudal transverse processes and a discussion of several new characteristics based on perspectives derived from recently described abelisauroids. Pycnonemosaurus nevesi differs from other abelisaurids based on the following features: a pubis with a small rounded foot and a ventrally-bowed anterior distal end; posterior caudal vertebrae with a hook-shaped transverse process that has an anterodistal expansion that is short and bowed; a strong and massive tibia with a well-developed lateral malleolus that is ventrally expanded. The unfused sutures represent signs of skeletal immaturity, but the specific ontogenetic stage is still uncertain. The current phylogenetic analysis suggests strongly relationship within Pycnonemosaurus and the most-derived abelisaurids (e.g Carnotaurus and Aucasaurus).
阿贝力龙科兽脚亚目恐龙在白垩纪时期的冈瓦纳大陆最为繁盛。2002年，凯尔纳和坎波斯命名的内氏密齿龙是首个从包鲁群（巴西，上白垩统）中描述的阿贝力龙科恐龙。然而，其最初的描述是基于数量有限的化石与其他阿贝力龙科恐龙的比较。在本文中，我对内氏密齿龙的形态进行了新的描述，包括三块新的尾椎横突，并基于最近描述的阿贝力龙类的视角讨论了几个新特征。内氏密齿龙与其他阿贝力龙科恐龙的区别在于以下特征：耻骨具有小的圆形足部，前端远端腹侧弯曲；后段尾椎的横突呈钩状，前远端扩展短且弯曲；胫骨粗壮，外侧踝发育良好且腹侧扩展。未愈合的缝线表明骨骼未成熟，但具体的个体发育阶段仍不确定。目前的系统发育分析强烈表明内氏密齿龙与最衍生的阿贝力龙科恐龙（如食肉牛龙和奥卡龙）之间存在亲缘关系。
