LATE PALEOZOIC EVOLUTION OF THE CAENOGASTROPODA: LARVAL SHELL MORPHOLOGY AND IMPLICATIONS FOR THE PERMIAN/TRIASSIC MASS EXTINCTION EVENT
LATE PALEOZOIC EVOLUTION OF THE CAENOGASTROPODA: LARVAL SHELL MORPHOLOGY AND IMPLICATIONS FOR THE PERMIAN/TRIASSIC MASS EXTINCTION EVENT
复制标题
蜥腹足类晚古生代演化：幼虫壳形态及其对二叠纪/三叠纪大规模灭绝事件的影响
作者：
A. Nützel;Hua
本文根据中国南方晚二叠世、美国宾夕法尼亚期和澳大利亚早石炭世保存异常完好的材料，对晚古生代新腹足类几个属的代表作了研究。该材料具有保存完好的原贝壳，这在古生代腹足类中相对罕见。原海螺的形态，特别是营养幼虫壳的形态，提供了重要的分类和系统发育信息。它有助于识别收敛，这在腹足纲中很常见。本文还讨论了以下分类群的幼虫壳形态，并作了图解：扁螺属（角螺科）、欧文旋螺属（Erwinispira n.）gen.（Erwinispirinae n.亚家族），Propupaspira（Propupaspiridae）、Soleniscus（Soleniscus）、Meekospiridae和Chlorozyga（Imoglobidae）。新物种Meekospira？solenisiciforma描述。主要的诊断功能的顺序Procaenogastropoda，一个流畅的protoconch/teleoconch的过渡，可能代表了一个解释性的人工制品。在原新腹足目的几个属中，可以看到一个突变，表明变态。因此，原新腹足类的单系性受到质疑，该分类单元被推翻。晚二叠世腹足动物群中的新腹足类以典型的晚古生代属和科为主，而早三叠世的特点是新腹足类属的动物群几乎完全更替。
Abstract Representatives of several genera of late Paleozoic Caenogastropoda have been studied based on exceptionally well-preserved material from the latest Permian of south China, the Pennsylvanian of the United States, and the Early Carboniferous of Australia. This material has well-preserved protoconchs which are relatively rare in Paleozoic gastropods. The morphology of the protoconch and especially that of planktotrophic larval shells gives crucial taxonomic and phylogenetic information. It helps to recognize convergence, which is common in Gastropoda. The larval shell morphology of the following taxa is discussed and illustrated: Platyzona (Goniasmatidae), Erwinispira n. gen. (Erwinispirinae n. subfam.), Propupaspira (Propupaspiridae), Soleniscus (Soleniscidae), Meekospiridae, and Chlorozyga (Imoglobidae). The new species Meekospira? solenisiciforma is described. The main diagnostic feature of the order Procaenogastropoda, a fluent protoconch/teleoconch transition, probably represents a preservational artifact. An abrupt transition indicating metamorphosis can be shown for several genera which have been assigned to the Procaenogastropoda. Therefore, the monophyly of the Procaenogastropoda is questioned, and the taxon is refuted. While the caenogastropods of latest Permian gastropod faunas are dominated by typical late Paleozoic genera and families, the Early Triassic is characterized by an almost complete faunal turnover of caenogastropod genera.