The taxonomy of an early ancestor of Recent Priapulidae, Xiaoheiqingella peculiaris (= Yunnanpriapulus halteroformis Huang et al., 2004) from the Early Cambrian Chengjiang fossil Lagerst?tte, is revised. Morphological...The taxonomy of an early ancestor of Recent Priapulidae, Xiaoheiqingella peculiaris (= Yunnanpriapulus halteroformis Huang et al., 2004) from the Early Cambrian Chengjiang fossil Lagerst?tte, is revised. Morphological characters comprise a pair of caudal appendages rather than a single appendage flanking the trunk end and a possible urogenital duct found inside the preanal region. An addi- tional extremely rare fossil priapulid worm, Paratubiluchus bicaudatus gen. nov., sp. nov. is also described herein. Its diagnostic characters are: an introvert bearing 25 longitudi- nal rows of scalids, a distinct neck region, no annulus on the oval trunk, and a pair of caudal appendages. The proportion of body parts is similar in size to that of loricate larvae of Recent priapulids and larva-formed Palaeopriapulitidae. Taking account of the features of Xiaoheiqingella, bicaudal appendages are considered to be a synapomorphy of Pri- apulidae and Tubiluchidae. Paratubiluchus gen. nov. is most likely a candidate for the ancestor of the Tubiluchidae; it probably originated from a larva-formed priapulid with 25 rows of scalids, thus representing an intermediate link be- tween the priapulids in mature-form and the priapulids with lorica.展开更多
The Early Cambrian Chengjiang Biota of China has preserved many species of vermiform animals in exquisite detail,which provide a unique window into the origin and early evolution of different vermiform phyla.This arti...The Early Cambrian Chengjiang Biota of China has preserved many species of vermiform animals in exquisite detail,which provide a unique window into the origin and early evolution of different vermiform phyla.This article reviews and discusses the forty-five Chengjiang vermiform animals discovered so far,and specifically comments on the phylogeny,modes of life,evolutionary significance as well as existing debates concerning the Chengjiang priapulid and lobopodian phyla.This article analyzes existing problems with Chengjiang vermiform morphological research and highlights various factors that affect the final preserved fossil morphology,including taphonomy and shape change caused by vermiform movement,as well as proposing that Anningvermis multispinosa and Corynetis brevis are synonymous.Chengjiang vermiform animals displayed a great diversity of morphologies and ecological roles,which is significant for understanding the origin and evolution of early metazoans;the potential for future research is enormous but needs to be broadened by interdisciplinary work involving taphonomy,geochemistry,cladistics,and genetics.展开更多
基金supported by the National Natural Science Foundation of China(Grant NOS.40332016 and 30270207)the National "973" Project(Grant No.G-2000077702)
文摘The taxonomy of an early ancestor of Recent Priapulidae, Xiaoheiqingella peculiaris (= Yunnanpriapulus halteroformis Huang et al., 2004) from the Early Cambrian Chengjiang fossil Lagerst?tte, is revised. Morphological characters comprise a pair of caudal appendages rather than a single appendage flanking the trunk end and a possible urogenital duct found inside the preanal region. An addi- tional extremely rare fossil priapulid worm, Paratubiluchus bicaudatus gen. nov., sp. nov. is also described herein. Its diagnostic characters are: an introvert bearing 25 longitudi- nal rows of scalids, a distinct neck region, no annulus on the oval trunk, and a pair of caudal appendages. The proportion of body parts is similar in size to that of loricate larvae of Recent priapulids and larva-formed Palaeopriapulitidae. Taking account of the features of Xiaoheiqingella, bicaudal appendages are considered to be a synapomorphy of Pri- apulidae and Tubiluchidae. Paratubiluchus gen. nov. is most likely a candidate for the ancestor of the Tubiluchidae; it probably originated from a larva-formed priapulid with 25 rows of scalids, thus representing an intermediate link be- tween the priapulids in mature-form and the priapulids with lorica.
基金supported by National Natural Science Foundation of China (Grant No. 40730211)National Basic Research Programme of China (Grant No. 206CB806400)Natural Science Foundation of Department of Science and Technology of Yunnan Province (Grant No. 2005D002Z)
文摘The Early Cambrian Chengjiang Biota of China has preserved many species of vermiform animals in exquisite detail,which provide a unique window into the origin and early evolution of different vermiform phyla.This article reviews and discusses the forty-five Chengjiang vermiform animals discovered so far,and specifically comments on the phylogeny,modes of life,evolutionary significance as well as existing debates concerning the Chengjiang priapulid and lobopodian phyla.This article analyzes existing problems with Chengjiang vermiform morphological research and highlights various factors that affect the final preserved fossil morphology,including taphonomy and shape change caused by vermiform movement,as well as proposing that Anningvermis multispinosa and Corynetis brevis are synonymous.Chengjiang vermiform animals displayed a great diversity of morphologies and ecological roles,which is significant for understanding the origin and evolution of early metazoans;the potential for future research is enormous but needs to be broadened by interdisciplinary work involving taphonomy,geochemistry,cladistics,and genetics.
