Anatomy and Relationships of the Middle Permian Varanopid Heleosaurus scholtzi Based on a Social Aggregation from the Karoo Basin of South Africa
Anatomy and Relationships of the Middle Permian Varanopid Heleosaurus scholtzi Based on a Social Aggregation from the Karoo Basin of South Africa
复制标题
基于南非卡鲁盆地社会聚集的中二叠世巨蜥龙scholtzi的解剖和关系
DOI：
10.1671/039.029.0209
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发表时间：
2009
期刊：
影响因子：
3.6
通讯作者：
S. Modesto
中科院分区：
文献类型：
--
作者：
J. Botha;S. Modesto
摘要描述了南非卡鲁盆地中二叠世龙的两个年龄组的个体解剖。这些骨骼可以识别出斯库茨鱼的新特征，包括枕骨的强烈前倾，四颈骨不在颞骨窗外，上颌-前额接触，以及上颌-四颈接触。除了这些特征之外，鳞片和Jugal之间没有背部接触，这使得我们可以将H.Studtzi归入变足类分支分枝分龙亚科。利用文献中扩充的数据矩阵对瓦龙科的系统发育进行分析，认为海龙是瓦龙亚科中海龙属的姊妹分类单元。这种姐妹群关系和Mycterosaurinae的单系关系都很弱，只要多走一步就会崩溃。然而，在分析中发现的许多分支显示出相同的支持水平，这表明需要对varanopid进行进一步的研究。
ABSTRACT The anatomy of individuals is described from a ‘pelycosaur’ aggregation preserving two age classes, from the Middle Permian of the South African Karoo Basin, that have been referred to Heleosaurus scholtzi. These skeletons allow the recognition of new features for H. scholtzi, including a strong anterior inclination of the occiput, exclusion of the quadratojugal from the temporal fenestra, a maxilla-prefrontal contact, and a maxilla-quadratojugal contact. In addition to some of these features, the absence of an anterodorsal contact between the squamosal and the jugal allows us to assign H. scholtzi to the varanopid clade Mycterosaurinae. Phylogenetic analysis of Varanopidae using an augmented data matrix from the literature positions Heleosaurus as the sister taxon of Elliotsmithia within the varanopid subfamily Mycterosaurinae. Both this sister-group relationship and the monophyly of Mycterosaurinae are weak and collapse with one extra step. Many of the clades discovered in the analysis exhibit the same support level, however, indicating that further studies on varanopids are needed.