Smith Adam S, Dyke Gareth J
School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Republic of Ireland.
Naturwissenschaften. 2008 Oct;95(10):975-80. doi: 10.1007/s00114-008-0402-z. Epub 2008 Jun 4.
The predatory pliosaurs were among the largest creatures ever to inhabit the oceans, some reaching gigantic proportions greater than 15 m in length. Fossils of this subclade of plesiosaurs are known from sediments all over the world, ranging in age from the Hettangian (approximately 198 Myr) to the Turonian (approximately 92 Myr). However, due to a lack of detailed studies and because only incomplete specimens are usually reported, pliosaur evolution remains poorly understood. In this paper, we describe the three dimensionally preserved skull of the giant Jurassic pliosaur Rhomaleosaurus cramptoni. The first phylogenetic analysis dedicated to in-group relationships of pliosaurs allows us to hypothesise a number of well-supported lineages that correlate with marine biogeography and the palaeoecology of these reptiles. Rhomaleosaurids comprised a short-lived and early diverging lineage within pliosaurs, whose open-water top-predator niche was filled by other pliosaur taxa by the mid-late Jurassic.
掠食性上龙是曾经栖息在海洋中的最大生物之一，有些上龙的体型极为巨大，长度超过15米。这种蛇颈龙亚目的化石在世界各地的沉积物中均有发现，年代范围从赫唐阶（约1.98亿年前）到土仑阶（约9200万年前）。然而，由于缺乏详细研究，且通常报道的只是不完整的标本，上龙的进化过程仍鲜为人知。在本文中，我们描述了巨型侏罗纪上龙克氏强喙龙三维保存的头骨。首次专门对上龙类群内部关系进行的系统发育分析，使我们能够推测出一些有充分支持的谱系，这些谱系与海洋生物地理学以及这些爬行动物的古生态学相关。强喙龙科是上龙类中一个存在时间较短且分化较早的谱系，到侏罗纪中后期，其开阔水域顶级捕食者的生态位被其他上龙类群所占据。
