瓮安生物群中海绵化石的新证据  

New Evidences of Sponge Fossils in the Weng'an Biota

作　　者：曹芳[1] 朱士兴[1] 

机构地区：[1]中国地质调查局天津地质矿产研究所,300170

出　　处：《地质学报》2001年第3期289-291,T001,T002,共5页Acta Geologica Sinica

基　　金：中国地质调查局地层古生物研究中心(宜昌地质矿产研究所)资助项目(编导J1.2.6)的成果

摘　　要：近年来笔者依据现存的瓮安生物群中一些海绵及动物胚胎化石标本的研究,对那些可能的球形海绵体及有争议的海绵幼虫标本进行了简略的评述。本文提供的保存完好的具单轴骨针的球形海绵体化石及可能的海绵幼虫标本,对于陡山沱期出现海绵动物的推测提供了新的证据。In recent years, fossils recognized as sponges and animal embryos have been reported in the Doushantuo phosphate rocks from the Guizhou Province (Li et al. ,1998, Xiao et al. ,1998). Zhang et al. (1998) disagreed with the interpretation of Li et al. that some of the needle-formed structures were monaxial spicules of sponges. They considered that these structures could be detached broken spines of collapsed Acritachs.Observation of specimens at hand revealed that the needle-shaped structure occurred only within the globular bodies, not anywhere along the crack or in surrounding matrix (P1. I -A and B, P1. II -A and B). It is monaxial and quite strong, with two tapering ends (P1. I -C). These characters are distinctly different from the spines of Acritarch illustrated in Zhang et al. (1998, Fig. 1). Based on the shoe -shaped morphology and dense peripheral flagella, some specimens were first identified as the parenchymella larvae of sponges by Li et al. (1998, Fig. 2E). Zhang et al. held that the interpretation of Li et al. is questionable, and reinterpreted as collapsed Acritarch (Ericiasphaera sp. ). The authors recognized that the specimens illustrated in Zhang et al. (1998, Fig. 1, B and D) are not to be compared with the specimen illustrated by Li et al. (1998, Fig. 2E) in the flexible outline and the shoe-shaped morphology. Therefore, the two cannot be mentioned in the same breath. Extant specimens at our disposal are (PL I -F, PL II -C) similar to those illustrated by Li et al. (1998, Fig. 2E). Whether or not they are larvae of sponges, it is not determined as yet. According to the observation of extant specimens, we tend to the interpretation of the sponges as monaxial spicules. Therefore, this paper illustrates some specimens that are well preserved and provides a conclusive evidence for the existence of sponges in the Weng'an Biota.

关 键 词：海绵化石 瓮安生物群 磷块岩 陡山沱组 动物胚胎化石 球形海绵体 单轴骨针 

分 类 号：Q914[天文地球—古生物学与地层学]