Restudy Of The Fuxianhuiid Athropods From Cambrian Series 2,Eastern Yunnan

The Chengjiang Lagerst?tte(Series 2,Stage 3),the Xiaoshiba Lagerst?tte(Series 2,Stage 3)and the Guanshan Lagerst?tte(Series 2,Stage 4)in the Cambrian in eastern Yunnan,China,are Cambrian representatives of Burgess Shale-Type Lagerst?ttens.Soft bodied fossils from these Lagerst?tten provide important evidence for the origin and early evolution of metazoans during the Cambrian explosion.The fuxianhuiid animal fossils are one of the important groups of the Cambrian arthropods.Currently,all known fuxianhuiids in the world are restricted from these three Lagerst?ttens.In this dissertation,the Fuxianhuiids specimens collected in these three Lagerst?ttens were used as research materials to study their morphology,classification,phylogeny and ontogeny,to provide basic data for a better understanding of the early evolution process and mechanism of euarthropods.Fuxianhuiids currently contain seven species,namely Fuxianhuia protensa Hou,1987,Chengjiangocaris longiformis Hou ? Bergstr?m,1991,and Liangwangshania biloba Chen,2005,from the Chengjiang Lagerst?tte;Fuxianhuia xiaoshibaensis Yang et al.,2013,Chengjiangocaris kunmingensis Yang et al.,2013,and Alacaris mirabilis Yang et al.,2018,from the Xiaoshiba Lagerst?tte;Guangweicaris spinatus Luo et al.,2007,from the Guanshan Lagerst?tte.The author collected six specimens except A.mirabilis,and used detailed optical microscopy,fluorescence microscopy,computed tomography,etc.to carry out detailed morphological observation and systematic research,and achieve the following new findings:(1)Multiple phenotypes of tergopleurae,telson and lateral telson processes were found in F.protensa;two pair of appendages in each of opisthothoracic tergite;interspecies difference in number of thoracic and abdominal tergites.(2)There are intraspecific differences in the number of opisthothoracic and abdominal segments of F.xiaoshibaensis;the telson has 2phenotypes.(3)The tripartite hypostome and specialized post-antennal appendages(SPAs)of C.longiformis were observed for the first time;the number of body segments was found to be up to 26(different from the 22 previously reported);the medial podomeres of the prothoracic limbs have triangular nodes;four pair of appendages in each of opisthothoracic tergite;the telson has a pair of lateral processes on both sides.(4)L.biloba has 6 segments on the prothorax;each axial area of the tergite has a pair of carina.Shankouia.zhenghei and L.biloba display extremely similar morphology,except that the posterior lateral edge of the carapace and the lateral processes showed two types of morphology respectively: smooth and spiny edge.(5)Newly recognised features of G.spinatus include tripartite hypostome,a pair of SPAs,opisthothoracic appendage composed of at least 11 podomeres,each bearing a large,subpentagonal spine,a triangular telson,two pairs of spines on the posteroventral margin of the terminal abdominal somite and a pair of leaf-shaped lateral processes.A single specimen previously assigned to this species is tentatively recognised as the“trilobitomorph” Longquania bispinosa Luo and Hu.Based on careful observation of specimens,the author has achieved the following new understanding:(1)S.zhenghei and L.biloba are sexual dimorphism of the same species,and S.zhenghei is a synonym of L.biloba.(2)L.biloba is a sister group of other fuxianhuiids and a new family can be established.(3)Pisinnocaris subconigera is not a larva of F.protensa;P.subconigera is not a synonym of F.protensa.According to the existing research materials.During the growth and development of C.longiformis,it may have the phenomenon of anamorphosis.(4)Liwangshaia sp.was found in the Xiaoshiba Lagerst?tte,which increased the fauna association between this Lagerst?tte and the Chengjiang Lagerst?tte,supporting the fact that the Xiaoshiba Lagerst?tte and the Chengjiang Lagerst?tte are not completely different,but a statement of two parts of a series of specifically preserved horizons that are linked by similar burial methods and inherited fauna.