微型腕足动物Lambdarina在广西隆安下石炭统的发现——兼论Lambdarinoidea超科的演化历史

Discovery of the micromorphic brachiopod Lambdarina from the Lower Carboniferous of Long’an,Guangxi,with remarks on the evolutionary history of the superfamily Lambdarinoidea

本文报道了来自广西隆安石炭系杜内阶上部的一种微型小嘴贝类Lambdarinoidea超科的腕足动物,即Lambdarina cf.sinensis。基于新发现标本和前人记述的lambdarinoids类腕足动物化石记录,本文讨论了这类腕足动物的迁移扩散演化历史,认为这一类群的早期分子在法门期出现于欧洲中部,于早石炭世杜内期在古特提斯洋东部的华南板块经历了多样性快速辐射,而后在杜内期晚期至维宪期迁移扩散至古特提斯洋西部的欧洲地区和冈瓦纳大陆东北缘的澳大利亚,并在壳体轮廓和隆槽等特征上体现出两种不同的演化分支。根据所有已报道的lambdarinoids化石记录可以推断,lambdarinoids喜居于低纬度温暖的静水环境。

A species of the superfamily Lambdarinoidea(Brachiopoda),namely Lambdarina cf.sinensis,from the Tournaisian of Long’an,Guangxi is described herein.The evolutionary history of this micromorphic rhynchonellid group is discussed based on their geologic and palaeogeographic distribution from the reported fossil records.The early lambdarinoids seem to appear first in central Europe during the Famennian and then migrated to the South China Plate where they experienced a biodiversification during the Tournaisian.The late Tournaisian and Visean witnessed the dispersal of succeeding lambdarinoid taxa to Europe of the western Paleo-Tethys Ocean and Australia on the northeastern margin of the Gondwana.Two evolutionary lineages are proposed here according to shell outlines and development of median ridge-like folds on the ventral valve.The lambdarinoids are supposed to favor warm and low-energic habitats at low latitude.