云南东部早寒武世关山生物群吐卓虫与龙泉虫再研究

发布时间：2018-09-09 15:29

【摘要】：吐卓虫{Tuzoia)是一类大型双瓣壳节肢动物,广泛分布于全球的寒武系地层中。本文着重研究了我国云南东部早寒武世(寒武系第二统第四阶)关山生物群中的网纹吐卓虫和瘤状吐卓虫,描述了一吐卓新种,即多刺吐卓虫(Tuzoia multispinosa sp. nov.)。基于较多的标本对瘤状吐卓虫{Tuzoia tylodesa Luo et Hu,2006)的细节特征进行了完善并重新修订了其种征,并对其个体发育做了初步的探讨研究。长期以来,学者们认为关山生物群中只有中华吐卓虫(Tuzoia sinensis Pan,1957)一种,后来虽然有过新种的报道,但由于其标本保存差且数量稀少而被认为是中华吐卓虫的晚出同物异名。笔者通过对采集到的大量吐卓虫标本进行细致的研究,发现并描述了一种新的壳面具网纹构造的吐卓虫。该吐卓虫无论在壳体形态、边缘刺的数量和排列方式上与同层位产出的中华吐卓虫和瘤状吐卓虫有着明显的差异,与世界其他地区寒武系地层中所产出的吐卓虫也有显著的不同。瘤状吐卓虫自从2006年被发现和报道以来,由于标本的相对稀少,后来学者对其鲜有进一步的研究描述。笔者在长期的野外工作中采集到了相对较多的该种标本(100余块),其中多数标本保存完好,笔者根据一块保存精美的标本对该种吐卓虫的形态特征进行了修订和完善,并建议将吐卓虫的属征进行修改,以包含具有不同壳面构造的(网纹与瘤状)吐卓虫的形态特征。瘤状吐卓虫保存有软体构造,包括视觉器官、伸出壳外的体节和可能的外肢构造等,这是吐卓虫被报道(Walcott,1912)至今一百多年来首次有软体附肢的发现(除视觉器官),也是瘤状吐卓虫第一块有软体构造保存的标本。本文基于壳体的形态大小、边缘刺的差异和壳面纹饰的不同,对瘤状吐卓虫的个体发育进行了初步的研究,将其发育过程分为幼年期(壳体长度小于2厘米)、青年期(壳体长度位于2厘米与5厘米之间)和成年期(壳体长度大于5厘米)三个阶段。龙泉虫(Longquania)属于光甲虫类(Aglaspidids)节肢动物,在关山生物群虫非常少见,本文根据采集到的保存完好的数块标本对龙泉虫的形态特征进行了较完善的描述。
[Abstract]:Tuzoia is a class of large bivalve arthropods widely distributed in the Cambrian strata around the world. In this paper, the early Cambrian (fourth order of the Cambrian) Guanshan biota in eastern Yunnan are studied emphatically. The new species, (Tuzoia multispinosa sp. nov.)., are described in this paper. Based on more samples, the detailed characteristics of Tuzoia tylodesa Luo et Hu,2006 were improved and its characteristics were revised, and its ontogeny was studied. For a long time, scholars think that there is only one species of (Tuzoia sinensis Pan,1957 in the Guanshan biota. Although a new species has been reported later, it is considered to be the late synonym of T. chinensis due to its poor preservation and rare number of specimens. Based on the detailed study of a large number of samples of Eucalyptus, a new type of Tucalyx was found and described in this paper. There were significant differences in shell shape, number and arrangement of edge spines between the sprue spp and the sprue spp in the same layer, respectively, in the shell shape, the number of spines and the arrangement of the spiny spines in the same layer. There is also a significant difference from the other Cambrian strata in the world. Since its discovery and report in 2006, due to the relative scarcity of specimens, there have been few further studies on it. The author has collected more specimens (more than 100 pieces) in the long field work, most of which are well preserved. According to a beautifully preserved specimen, the author has revised and perfected the morphological characteristics of this species. It is also suggested that the generic sign of Eucalyptus should be modified to include the morphological characteristics of the sprue with different shell structures (reticulate and tuberous). The neoplasm has soft structures, including visual organs, segments extending out of the shell, and possible structures of the outer limb. This is the first discovery of soft appendages (except for visual organs) reported by Walcott,1912 in more than a century. It is also the first specimen with soft structure to be preserved. Based on the shape and size of the shell, the difference of the edge prickles and the difference of the shell ornamentation, the ontogeny and development of the tuberous spruce were studied in this paper. The developmental process was divided into three stages: infancy (shell length < 2 cm), youth (shell length between 2 cm and 5 cm) and adult stage (shell length > 5 cm). The (Longquania) belongs to the (Aglaspidids) arthropod of Photomonas, which is very rare in Guanshan biota. The morphological characteristics of the insect are described in this paper according to several well-preserved specimens collected in this paper.
【学位授予单位】：云南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：Q915

【参考文献】