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Dissection and Flat-mounting of the Threespine Stickleback Branchial Skeleton

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Morphological disparity in the cambrian.

D E Briggs, R A Fortey, M A Wills

Science (New York, N.Y.)

|June 19, 1992

Summary

This summary is machine-generated.

Morphological disparity in arthropods today is similar to that seen in the Cambrian period. The perceived "Cambrian explosion" of diversity may be an overestimation due to classification issues.

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Area of Science:

Evolutionary Biology
Paleontology
Arthropod Biology

Background:

The Cambrian explosion is often cited as a period of unprecedented evolutionary radiation.
Arthropod morphology has been studied to understand evolutionary patterns.

Purpose of the Study:

To analyze and compare the morphological disparity of Cambrian arthropods with extant arthropods.
To re-evaluate the significance of the Cambrian explosion in arthropod evolution.

Main Methods:

Comparative morphological analysis of fossil and extant arthropod taxa.
Taxonomic review of "problematic" taxa from the Cambrian period.

Main Results:

Morphological disparity in living arthropods is comparable to that of Cambrian arthropods.
The extent of unique morphological designs from the Cambrian explosion appears to have been overestimated.
Many "problematic" Cambrian taxa are artifacts of an insufficient classification system.

Conclusions:

Special evolutionary mechanisms may not be required to explain early metazoan radiation.
Arthropod evolution shows a consistent pattern of morphological diversity over geological time.
Taxonomic practices significantly influence the interpretation of evolutionary history.