Abstract

Crustaceans are predominantly aquatic arthropods with a characteristic naupliar stage. Their known evolutionary history extends at least from the Early Cambrian. They display many features convergent with the chelicerates, uniramians and trilobites and formerly were classified with these groups in Arthropoda. It seems more appropriate to study the origins of Crustacea by reference to their Cambrian representatives than by seeking to establish particular intuitions concerning early crustaceans based on a knowledge of living forms only. Among Cambrian fossils, the lobopod Aysheaia is irrelevant to crustacean origins. Similarly, the living Tardigrada are best consigned to a separate phylum although they seem to be a related group with several primitive characters and are likely, on zoogeographic grounds, to have had a long evolutionary history. Assuming that Crustacea are monophyletic, the existing fossil record dictates that the ancestral taxon possessed a complex of characters out of which evolved (during Cambrian times) at least: bradoriids and other primitive ostracode-like animals; Canadaspis and other phyllocarid-like forms; Branchiocaris and similar notostracan-like forms. Several other Cambrian taxa may be either true crustaceans or examples of convergence. Some show similarities to anostracans and conchostracans. The diversity and complexity of the Cambrian fossils suggest that a basic crustacean facies was already established by the Late Precambrian (Ediacaran).

 
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Bibliographic Data

Short Form
McKenzie, 1984, Aust. Mus. Mem. 18(3): 21–43
Author
K. G. McKenzie
Year
1984
Title
On the origin of Crustacea
Serial Title
Australian Museum Memoir
Volume
18
Issue
3
Start Page
21
End Page
43
DOI
10.3853/j.0067-1967.18.1984.370
Language
English
Date Published
31 March 1984
Cover Date
31 December 1983
ISSN
0067-1967
CODEN
AUNMA5
Publisher
The Australian Museum
Place Published
Sydney, Australia
Subjects
CRUSTACEA; EVOLUTION
Digitized
09 September 2009
Reference Number
370
EndNote
/Uploads/Journals/17625/370.enw
Title Page
/Uploads/Journals/17625/370.pdf
File size: 137kB
Complete Work
/Uploads/Journals/17625/370_complete.pdf
File size: 3212kB