|Affinities and early evolution of the Crustacea: the evidence of the Cambrian fossils|
Briggs, D.E.G. (1983). Affinities and early evolution of the Crustacea: the evidence of the Cambrian fossils, in: Schram, F.R. (Ed.) Crustacean phylogeny. Crustacean Issues, 1: pp. 1-22
In: Schram, F.R. (Ed.) (1983). Crustacean phylogeny. Crustacean Issues, 1. A.A. Balkema: Rotterdam, The Netherlands. ISBN 90-6191-231-8. 372 pp., more
In: Schram, F.R. (Ed.) Crustacean Issues. Balkema/CRC Press/Taylor & Francis: Rotterdam. ISSN 0168-6356, more
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The only reliable character available to identify Crustacea among the wide diversity of Cambrian arthropods is the arrangement of the cephalic appendages. These are rarely preserved, and this review is confined to a consideration of arthropods with known soft-parts, particularly those of the Middle Cambrian Burgess Shale of British Columbia and the Upper Cambrian 'Orsten' of Sweden. The majority of Cambrian arthropods do not fall into easily defined groups; only the Crustacea of the major living taxa are represented. A critical review of the fossils reveals that only two crustacean classes are present in the Cambrian, the Phyllocarida and the Ostracoda. Previous discussions of crustacean affinity considered many of the other Cambrian arthropods to belong with the trilobites in the Class Trilobitoidea, since shown to be invalid, thus obscuring their potential significance in early arthropod evolution. A consideration of all the well preserved Cambrian arthropods reveals no unequivocal evidence of crustacean affinities, but the possibility of a common origin with at least some other arthropods cannot be ruled out.