论文部分内容阅读
记述了四川省自贡市汇东新区自贡市乳品厂发现的西蜀鳄一新种——周氏西蜀鳄(Hsisosuchus chowi sp.nov.)。新种区别于西蜀鳄已知种的特征是:鼻骨后部沿缝合线有一浅的纵凹,额骨的眶缘向上凸起成嵴,沿额骨缝合线也隆起成一微弱的纵嵴,上颞窝的内侧缘向上凸起呈明显的嵴,顶骨具一前中突,侧视颧骨腹缘呈明显的波曲状,眶后骨前侧角约90°,鳞骨后侧突特别拉长,向侧下后方伸展,使鳞骨侧缘明显向内侧弓曲,左右外枕骨的枕髁部分不相接,翼骨的腹中嵴源于翼骨主体部分,内鼻孔位置比较靠前。此外,齿骨外面和夹板骨腹面具有发达的沟和嵴状雕饰,夹板骨参与下颌联合的部分比较长,肩胛片异常扩展,乌喙骨远端宽于近端,肱骨头增厚并强烈向内侧扩展,三角肌嵴发达,桡侧腕骨具发达的尺骨突,尺侧腕骨远端宽于近端,6列荐前部腹部骨板和3列尾部腹部骨板,也可能是周氏西蜀鳄的衍生特征,但这些性状在大山铺西蜀鳄中情况不明,有待更多的材料来证实。杨钟健、周明镇(1953)在建立西蜀鳄属之初就已注意到西蜀鳄是一种特化的鳄类,认为西蜀鳄不仅将原始特征和进步特征混存于一身,而且还具有一些一般鳄类所没有的独特性质。以此为基础,他们建立了西蜀鳄科。目前西蜀鳄类动物发现并不多,仅有1属2种,即重庆西蜀鳄和大山铺西蜀鳄,而且材料不完整,特别是头后骨骼保存不理想。周氏西蜀鳄的发现不仅扩大了西蜀鳄类的分布范围,而且还增加了我们对这一特化鳄类的认识。
A new species of Xishuushu discovered in the Zigong dairy plant in Huidong New District of Zigong City, Sichuan Province, is described - Hissosuchus chowi sp. Nov. The new species is different from the known species of Xishu Chuan is characterized by: the back of the nasal suture along the line there is a shallow depression, the frontal orbital rim protruding up into a ridge, along the frontal suture also raised a weak vertical ridge, The medial edge of the upper fossa lit up prominent crista, with a front parietal protrusion, lateral ventral zygomatic showed a significant wave-like, anterior orbital anterior angle of about 90 °, the squamous dorsal prominence Elongated, backward to the side of the lateral expansion, so that the lateral side of the squamous bow curvature, left and right lateral occipital condyle does not contact with the wing of the canthal origin in the main part of the wing, the nose position more front . In addition, the outer surface of the spondylolisthesis and the spine of the splint with developed ditch and ridge-shaped carving, splint involvement in the mandibular part of the relatively long, abnormal expansion of the scapula, the distal end of the black beak is wider than the proximal end, the humeral head thickened and strongly Medial expansion, deltoid ridges developed, radial carpal ulnar developed ulna, ulnar carotid distal wider than the proximal, 6 anterior abdominal plate and the tail 3 abdominal plate, may also be West Zhou Xishan Crocodile derived characteristics, but these traits in the Dashishaipu crocodile situation is unknown, to be more material to confirm. Yang Zhongjian and Zhou Mingzhen (1953) had already noticed that Xishuushu was a specialized crocodile at the beginning of the establishment of the West Sichuan crocodile. They thought that the Xishu crocodile not only mixed the original features and the advanced features, but also had Some unique crocodile does not have the unique nature. Based on this, they established the West Sichuan Crocodile Branch. At present, there are not many species found in the western Sichuan alligator, only 1 genus and 2 species, that is, the western Sichuan alligator and Dashanpu Xishuushu alligator, and the material is not complete, especially the preservation of the posterior bones is not ideal. The discovery of Zhou’s Western Sichuan crocodile not only expanded the scope of the western Sichuan crocodile, but also increased our knowledge of this special crocodile.