Abstract

The Malacostraca appear to have been derived from epibenthic ancestors with many caridoid features. Despite their very long palaeontological record the Phyllocarida differ in so many respects from the basic eumalacostracan morphological and functional plan that they are regarded as unlikely ancestors and more probably an early diverging branch. The general morphology of the malacostracan cephalothorax and carapace is discussed and it is shown that the concept of a maxillary segment carapace common to all Crustacea is not valid. The malacostracan dorsal shield is produced by a fusion of terga and a free carapace fold is sometimes formed at its posterior margin. Some functional systems of the various caridoid Malacostraca are discussed. Attention is drawn to the unsolved problem of secondary segmentation after the alleged loss of a cephalothorax, e.g. in the Syncarida. The unsatisfactory status of the diagnosis of the superorder Peracarida is pointed out and a revision recommended.

 
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Bibliographic Data

Short Form
Dahl, 1984, Aust. Mus. Mem. 18(1): 1–5
Author
Erik Dahl
Year
1984
Title
Alternatives in malacostracan evolution
Serial Title
Australian Museum Memoir
Volume
18
Issue
1
Start Page
1
End Page
5
DOI
10.3853/j.0067-1967.18.1984.368
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: MALACOSTRACA
Digitized
09 September 2009
Reference Number
368
EndNote
/Uploads/Journals/17627/368.enw
Title Page
/Uploads/Journals/17627/368.pdf
File size: 112kB
Complete Work
/Uploads/Journals/17627/368_complete.pdf
File size: 666kB