Soft-part anatomy of the Early Cambrian bivalved arthropodsKunyangella and Kunmingella: significance for the phylogenetic relationships of Bradoriida
Xianguang Hou1,*, Mark Williams2, David J. Siveter2, Derek J. Siveter3,4, Richard J. Aldridge2 and Robert S. Sansom2
-Author Affiliations
1Yunnan Key Laboratory for Palaeobiology, Yunnan University, Kunming 650091, Yunnan Province, People's Republic of China
2Department of Geology, University of Leicester, University Road, Leicester LE1 7RH, UK
3Geological Collections, University Museum of Natural History, Oxford OX1 3PW, UK
4Department of Earth Sciences, University of Oxford, Parks Road, Oxford OX1 3PR, UK
*Author for correspondence (xghou@ynu.edu.cn).
Abstract
Bradoriids are small bivalved marine arthropods that are widespread in rocks of Cambrian to Early Ordovician age. They comprise seven families and about 70 genera based on shield (‘carapace’) morphology. New bradoriid specimens with preserved soft-part anatomy of Kunmingella douvillei(Kunmingellidae) are reported from the Early Cambrian Chengjiang Lagerstätte of China together with, for the first time to our knowledge, a second bradoriid species with preserved soft parts, Kunyangella cheni(Comptalutidae). Kunmingella douvillei has a 10-segmented limb-bearing body with uniramous ninth and tenth appendages and a series of homogeneous, apparently (proximal parts not preserved) unspecialized post-antennal biramous limbs with setose leaf-shaped exopods. Each endopod consists of five podomeres. A presumed penultimate instar of Ky. cheni preserves remnants of three head and two trunk appendages, and the adult is reconstructed as having four head appendages. This material allows testing of the affinity of the Bradoriida. Kunmingella is identified as a stem crustacean in character-based analyses, through both morphological comparisons and cladistic reconstructions. Global parsimony analysis recovers a monophyletic Bradoriida as the sister group to crown crustaceans.
Arthropoda Bradoriida Cambrian Chengjiang Lagerstätte China exceptional preservation
Footnotes
Received December 1, 2009.
Accepted February 2, 2010.
© 2010 The Royal Society
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NOTA DESTE BLOGGER:
Alguém sabe me dizer a quantas anda aquela pesquisa que encontrou resíduos de proteína em fóssil de T. rex? E o que isso agora significa? Partes moles em fósseis do Cambriano??? Cruz, credo... Valha-nos, São Darwin...
Xianguang Hou1,*, Mark Williams2, David J. Siveter2, Derek J. Siveter3,4, Richard J. Aldridge2 and Robert S. Sansom2
-Author Affiliations
1Yunnan Key Laboratory for Palaeobiology, Yunnan University, Kunming 650091, Yunnan Province, People's Republic of China
2Department of Geology, University of Leicester, University Road, Leicester LE1 7RH, UK
3Geological Collections, University Museum of Natural History, Oxford OX1 3PW, UK
4Department of Earth Sciences, University of Oxford, Parks Road, Oxford OX1 3PR, UK
*Author for correspondence (xghou@ynu.edu.cn).
Abstract
Bradoriids are small bivalved marine arthropods that are widespread in rocks of Cambrian to Early Ordovician age. They comprise seven families and about 70 genera based on shield (‘carapace’) morphology. New bradoriid specimens with preserved soft-part anatomy of Kunmingella douvillei(Kunmingellidae) are reported from the Early Cambrian Chengjiang Lagerstätte of China together with, for the first time to our knowledge, a second bradoriid species with preserved soft parts, Kunyangella cheni(Comptalutidae). Kunmingella douvillei has a 10-segmented limb-bearing body with uniramous ninth and tenth appendages and a series of homogeneous, apparently (proximal parts not preserved) unspecialized post-antennal biramous limbs with setose leaf-shaped exopods. Each endopod consists of five podomeres. A presumed penultimate instar of Ky. cheni preserves remnants of three head and two trunk appendages, and the adult is reconstructed as having four head appendages. This material allows testing of the affinity of the Bradoriida. Kunmingella is identified as a stem crustacean in character-based analyses, through both morphological comparisons and cladistic reconstructions. Global parsimony analysis recovers a monophyletic Bradoriida as the sister group to crown crustaceans.
Arthropoda Bradoriida Cambrian Chengjiang Lagerstätte China exceptional preservation
Footnotes
Received December 1, 2009.
Accepted February 2, 2010.
© 2010 The Royal Society
FREE PDF GRÁTIS
+++++
NOTA DESTE BLOGGER:
Alguém sabe me dizer a quantas anda aquela pesquisa que encontrou resíduos de proteína em fóssil de T. rex? E o que isso agora significa? Partes moles em fósseis do Cambriano??? Cruz, credo... Valha-nos, São Darwin...
