中国中生代哺乳动物研究进展

迄今为止,中国已知的中生代哺乳动物共有26属29种(包括3个未定种),时代分布从早侏罗世至晚白垩世。在中国新近发现的中生代哺乳动物中,除少数几种材料比较零星之外,大多数都有保存很好的头骨和骨架为代表。它们提供了认识哺乳动物高阶元之间的系统发育关系以及早期演化过程中特征转变的重要信息。过去几年中发现的中生代哺乳动物多数产于热河生物群中。这些化石代表了不同的哺乳动物大类,同时显示了在个体大小、运动姿态以及食性方面的较高的分异。多方面的分异确保了它们在同一个生态系统中能够占据不同的生态位。频繁的火山活动被认为是辽宁西部地区动物大量死亡的主要原因。像巨爬兽(Repenomamus giganticus)一样以睡眠姿势保存的标本,很可能意味着随火山喷发释放出的有毒气体参与造成了这样的灾难。

REVIEW OF RECENT ADVANCES ON STUDY OF MESOZOIC MAMMALS IN CHINA

Twenty-six named species of 23 genera have been known in China from the deposits ranging from the Early Jurassic to Late Cretaceous. Except a few taxa, most of recently discovered Mesozoic mammals in China are represented by well-preserved skulls and skeletons. They have greatly improved our knowledge of the relationships of the major mammalian lineages and the character transition during the evolution of early mammals. Some localities of the Jehol Biota produced most Mesozoic mammal fossils in the past several years. These fossils represent different major groups and show high diversity in body size, locomotory adaptation, and dietary. Such diversification ensures them to occupy different niches in the common ecosystem. Frequent volcanic eruptions in western Liaoning were primarily responsible for the massive death of animals. Specimens preserved in sleeping posture, like the type specimen of Repenomamus giganticus, may indicate that the emission of poisonous gas with the volcanic eruption was probably involved in causing the disaster.