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A specimen of Timoroblastus coronatus Wanner (Blastoidea: Fissiculata; Permian) with inverted basals

Published online by Cambridge University Press:  20 May 2016

Mike Foote
Mike Foote*
Affiliation:
Museum of Paleontology, University of Michigan, Ann Arbor 48109-1079
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Extract

Although basic skeletal design tends to be rather stable within classes and lower level taxa of echinoderms, Echinodermata as a phylum shows an enormous range of symmetries, including forms that are amorphous, bilateral, and pentameral. Variations in symmetry within taxa are not simply curiosities, but have been used to infer modes of development and patterns of evolution of symmetry (Lane and Webster, 1967; Macurda, 1980; Galloway, 1990). During a recent morphometric study (Foote, 1991) involving the blastoid collections of the University of Michigan Museum of Paleontology (UMMP), a specimen of the fissiculate blastoid species Timoroblastus coronatus was found with the azygous basal in the CD interray. This appears to represent the first reported case of basal inversion in this species, and increases the number of blastoid genera in which basal inversion is known to at least six.

Type
Paleontological Note
Information
Journal of Paleontology , Volume 67 , Issue 4 , July 1993 , pp. 681 - 682
Copyright
Copyright © The Paleontological Society 

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References

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