【摘要】：古蟲動物門是寒武紀(jì)最獨特、最神秘的動物類群之一,后口動物起源之謎可追溯至這一生物類群,因此古蟲類頗受古生物學(xué)家重視。位于我國云南東部的寒武系第二統(tǒng)第四階的關(guān)山生物群中古蟲動物化石豐富,目前已報道了古蟲動物的3個種,龍寶山古蟲(Vetulicola longbaoshanensis Yang et al.,2010)是其中之一。本文研究了關(guān)山生物群昆明高樓房剖面和武定興隆村剖面中保存較完好的龍寶山古蟲Vetulicola longbaoshanensis化石,并對其鰓部構(gòu)造做了詳細(xì)描述。龍寶山古蟲V.longbaoshanensis鰓部構(gòu)造比澄江生物群中古蟲屬的鰓部構(gòu)造更加復(fù)雜,鰓囊呈葫蘆狀,由前小后大的兩個囊狀構(gòu)造組成。在兩個囊狀構(gòu)造的連接處,能觀察到明顯的鰓裂和濃密的鰓絲。此外,通過對比關(guān)山生物群中和澄江生物群中古蟲類的前體長高比和鰓囊在前體的位置,本次研究還發(fā)現(xiàn)關(guān)山生物群中的古蟲動物和澄江生物群方口古蟲(Vetulicola rectangulata Luo et Hu,1999)在形態(tài)上極為相似,推測關(guān)山生物群中的古蟲類由方口古蟲(V.rectangulata)演化而來。同時,與澄江生物群中的方口古蟲動物相比,關(guān)山生物群中的古蟲動物的體型較大,前體長高比增加,鰓囊也隨之增大。這表明古蟲在激烈的生態(tài)競爭過程中已經(jīng)淘汰了個體較小的類型,也從一個側(cè)面反映了體型逐步增大是古蟲類在寒武紀(jì)的一個演化趨勢。
[Abstract]:The phylum Paleocephala is one of the most unique and mysterious fauna of the Cambrian. The origin mystery of hind mouth animal can be traced back to this biological group, so paleosperm has been paid much attention to by paleontologists. The fourth order of the Cambrian biota of the Cambrian in the eastern part of Yunnan Province is rich in fossils of Paleozoa fauna. Three species of Paleozoa have been reported at present, among which the (Vetulicola longbaoshanensis Yang et al.,2010 of Longbaoshan is one of them. In this paper, the well-preserved Vetulicola longbaoshanensis fossils of ancient worms in Guanshan biota, Kunming Gaoding and Xinglongcun, Wuding, are studied, and the Gill structure of them is described in detail. The Gill structure of V.longbaoshanensis in Longbaoshan is more complicated than that of Paleoptera in Chengjiang. The Gill sac is cucurbit-shaped and consists of two large structures. Obvious branchial cleft and dense branchial filaments can be observed at the junction of two cystic structures. In addition, by comparing the ratio of length to height of the forebody of Guanshan biota and Chengjiang biota, and the location of Gill sac in the precursor, the study also found that the paleoinsects in Guanshan biota and the (Vetulicola rectangulata Luo et Hu, in Chengjiang biota were found in this study. 1999) the morphology of Guanshan Biota is very similar. It is inferred that the paleoinsects in Guanshan biota evolved from V.rectangulata. At the same time, compared with Chengjiang biota, Guanshan biota has a larger size, higher ratio of precursor length to height, and larger Gill sac. This indicates that the palaeoworms have eliminated the smaller types of individuals in the fierce ecological competition, which also reflects that the gradual enlargement of the palaeosperm is an evolutionary trend of the Palaeodes in the Cambrian period.
【學(xué)位授予單位】：西北大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：Q915
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本文編號：2344696