Preservational folds simulating tergite junctions in tegopeltid and naraoiid arthropods |
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Authors: | LARS Ramsköld CHEN JUN-YUAN GREGORY D EDGECOMBE ZHOU GUI-QING |
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Institution: | Lars Rarnskold, Museum of Palaeontology, University of Uppsala, Norbyvagen 22, S-752 36 Uppsala, Sweden;Nanjing Institute of Geology and Palaeontology, Academia Sinica, Chi-Ming-Ssn, Nanjing 21 0008, People's Republic of China;Gregory D. Edge-combe, Australian Museum, 6 College Street, Sydney South, N.S. W. 2000, Australia |
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Abstract: | The exoskeleton in the Middle Cambrian Burgess Shale arthropod Tegopelte has previously been described as divided into tergites. Evidence from its sister taxon Saperion and from a Naraoia specimen from the Lower Cambrian Chengjiang fauna enables a reinterpretation of the suggested tergite boundaries in Tegopelte as preservational artefacts. They are considered here as folds that were formed during flattening of the undivided dorsal shield. As in the Naraoia specimen, the folds were initiated in the axial region between appendage pairs and then continue laterally. In Tegopelte and Saperion , segmentally arranged furrows in the axial region facilitated fold formation. Characters other than presence of thoracic tergites and pygidium must be used to assess the affinities of Tegopelte, Arthropoda, Tegopeltidae, tagmosis, segmentation, Chengjiang fauna, Burgess Shale. |
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