东北大兴安岭新发现早白垩世两栖动物群之研究

The Early Cretaceous Jehol Biota distributed in western Liaoning, southeastern Inner Mongolia and northern Hebei has yielded abundant amphibian fossils, providing important evidence on the early evolution of modern amphibian groups. The Greater Khingan Mountains area of northeastern China, including northeastern Inner Mongolia, and western Heilongjiang, had no documents of amphibian fossils. The Lower Cretaceous of this region, however, has the same volcanic rocks as well as interbeded sedimentary deposits, and the geological and paleontological surveys also have found the same invertebrate elements as those of the Jehol Biota flourished in western Liaoning, such as Ephemeropsis, Eosestheria, and a few isolated fishes. Just recently, some new fossil localities have been found in the municipal regions of Hulunbuir of Inner Mongolia and Qiqihar of Heilongjiang, which have yielded fossil fishes, amphibians, turtles, pterosaurs, birds and mammals. The amphibians among them include new taxa of both anurans and caudates, documenting their first co-occurrence in the Mesozoic localities of China. Based on the aforementioned fossils and localities, this project will organize fossil excavations and collections in this area, study the taxonomy and phylogeny of the amphibians and other vertebrate fossils, and investigate the faunal composition and evolution, as well as its relationship with the Jehol Biota of western Liaoning.

我国辽宁西部、内蒙古东南部和河北北部地区早白垩世热河生物群产出了丰富的两栖类化石，为研究现代两栖类群的早期演化提供了重要证据。东北大兴安岭地区，包括内蒙古东北部、黑龙江西部等地，过去一直没有两栖类化石的记录。大兴安岭地区的下白垩统同样有丰富的火山岩地层以及多层沉积夹层，以往地质古生物调查也发现了与辽西热河生物群完全相同的无脊椎动物化石分子（如三尾拟蜉蝣、叶肢介等）以及零星的鱼类化石。最近，在内蒙古呼伦贝尔以及黑龙江齐齐哈尔市下辖的地区，发现了几处新的脊椎动物化石地点，已经发现的脊椎动物化石有鱼类、两栖类、龟鳖类、翼龙、鸟类和哺乳动物，其中两栖类化石数量丰富，是我国中生代首次发现无尾类和有尾类共生的化石产地，并有重要新属种出现。本项目将以此为基础对上述化石地点进行发掘与采集，对发现的两栖动物及伴生脊椎动物群进行分类学和系统发育学研究，并探讨该地区动物群组成和演化及其与辽西热河生物群的关系。

在中国东北大兴安地区的下白垩统地层中发现了几处新的脊椎动物化石地点，产出鱼类、两栖类、龟鳖类、鸟类等脊椎动物化石，其中两栖类化石的数量极其丰富，也是我国中生代首次发现无尾类和有尾类共生的化石产地，并有重要的新属种出现。本项目理清大兴安岭地区早白垩世脊椎动物化石富集产出地层，并进行高精度的同位素测年；结合新的高精度平板CT扫描技术，进行大兴安岭地区早白垩世两栖类及其伴生脊椎动物的形态学、分类学及系统发育学等方面的传统古生物学研究。对同种的不同大小个体，进行个体发育学研究，判定不同发育阶段的骨骼学特征。基本完成了该项目的研究目标，完成了大兴安岭地区新发现无尾类和有尾类化石的骨骼形态学研究、分类系和系统发育学，并对已发表的中国中生代滑体两栖类进行了补充修订，同时对新地点两栖类的伴生脊椎动物，尤其是龟鳖类进行了形态学和分类学的研究。这些研究工作为了解大兴安岭地区早白垩世脊椎动物群的面貌、理解其与辽西热河脊椎动物群组成和演化特点的异同、以及中生代两爬类的古地理学和古气候学提供了基础数据，具有重要的意义。