贵州中寒武世凯里生物群双刺吐卓虫(Tuzoia bispinosa)个体发育的研究

ONTOGENESIS OF TUZOIA BISPINOSA(ARTHROPODA) FROM THE MIDDLE CAMBRIAN KAILI BIOTA,GUIZHOU,CHINA

大型双瓣壳节肢动物是凯里生物群中重要组成部分,其中吐卓虫属(Tuzoia)最为常见,化石标本达200多件。吐卓虫常见于全球早、中寒武世地层,地理分布广泛,在地层对比和古环境研究中具有重要意义。文章运用数理统计和对比研究的方法,详细检测130多块双刺吐卓虫(Tuzoia bispinosa Yuan and Zhao,1999)化石标本,发现明显可分为幼年期、青年期和成年期3个不同的生长发育阶段。文中探讨双刺吐卓虫的个体发育,确认先前建立的凯里生物群中Tuzoia的2个种:Tuzoia bispinosa和T.magna,应为Tuzoia bispinosa一种。

Large bivalved arthropods are common in Cambrian strata worldwide.Among these,Tuzoia occurs in the Early and Middle Cambrian and has a wide geographic distribution.Therefore,it is significant for correlations of Lower and Middle Cambrian stratigraphy and for paleoenvironmental interpretation.Tuzoia specimens are abundant in the Middle Cambrian Kaili Biota near Balang village,Jianhe County,Guizhou Province and specimens ranging from small larva to juveniles to mature individuals are present.More than two hundred specimens of Tuzoia bispinosa Yuan and Zhao 1999 from this locality are housed in the Guizhou University Paleontologic Museum.Based on detailed examination of 130 specimens of Tuzoia bispinosa,we describe the ontogenesis of this population using statistics and mathematical analysis.The 130 specimens of Tuzoia bispinosa analyzed represent three different ontogenetic stages.Additionally,we confirm that only a single species of Tuzoia is present in the Kaili Biota.This species was a swimming animal,which lived in shallow water platform habitats as well as in deep-water slope areas in inner and outer shelves.