Mid-Cretaceous fish assemblages in north-eastern Mexico: A case-study for the actinopterygian diversification and global palaeobiogeography

在对墨西哥东北部白垩纪脊椎动物（DFG FR 1314/4-1, 6-1, 7-1, 9-1, STI 128/9-1, 9-2, VW I/78866）的研究中，我们发现了许多保存完好的鱼类。其中之一是在新莱昂州的瓦列西略发现的早期Turonian鱼群，那里有各种鲨鱼和放光鳍动物分类群的完整标本，但被压碎了。关于Vallecillo鱼类组合的初步报告已经发表，但对该组合的综合全球研究仍有待完成。最近，人们对暴露在东北部科阿韦拉州Muzquiz北部的上Turonian -Coniacian层状灰岩有了新的关注。在这个地区，小型商业采石场出产的化石保存得非常完好。目前，科学界对其位置和组合一无所知。我们在Muzquiz的初步调查发现了几种鱼类（selac纲、全骨纲和硬骨鱼），其中甚至保存了精致的肌肉纤维和鳃丝，以及胃内容物的化石，有时是三维的。这两个地点，特别是Muzquiz，在对该分类群进行深入的解剖描述和根据同期古环境变化绘制演替鱼类组合的时间转换方面具有很大的潜力。本项目的主要目标是：1)了解中白垩纪墨西哥鱼类组合与邻近领域（特提斯中部、南大西洋、西内海和太平洋）的古生物地理联系。2)基于现有的鱼类多样化因果关系假设，测试白垩纪中期放射线翼鱼的全球辐射情景。

During our previous research work on Cretaceous vertebrates from NE Mexico (DFG FR 1314/4-1, 6-1, 7-1, 9-1, STI 128/9-1, 9-2, VW I/78866) we discovered several localities yielding numerous well-preserved fishes. One of these is the early Turonian fish assemblage at Vallecillo, Nuevo Leon, which yields complete but crushed specimens of various sharks and actinopterygian taxa. Preliminary accounts have already been published about the Vallecillo fish assemblage, but a synoptic global study of this assemblage is still pending. Recently, new attention has been paid to the Upper Turonian -Coniacian laminated marly limestones exposed north of Muzquiz in the northeastern state of Coahuila. In this area, small commercial quarries yield fossils, which are exceptionally well preserved. At present, localities and assemblages are unknown to the scientific community. Our initial survey at Muzquiz resulted in several species of fishes (selacheans, holosteans and teleosts) in which even delicate muscle fibres and gill filaments, as well as fossilised stomach contents are preserved, sometimes in three dimensions. Both localities, and especially Muzquiz, bear great potential to carry out thorough anatomical description of the taxa and to draw up the temporal turnover within the succession offish assemblages against coeval changes of the palaeoenvironment. The principal objectives of the present project are: 1) Understanding the palaebiogeographical links of the mid-Cretaceous Mexican fish assemblages with the adjacent realms (Central Tethys, South Atlantic, Western Interior Sea and Pacific). 2) Testing the scenario of a mid-Cretaceous actinopterygian worldwide radiation based on existing hypotheses about causality offish diversification.