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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

Breimer, A., and Macurda, D. B. Jr. 1972. The phylogeny of the fissiculate blastoids. Verhandelingen der Koninklijke Nederlandse Akademie van Wetenschappen, Afdeling Natuurkunde, Erste Reeks, 26:1–390.Google Scholar
Foote, M. 1991. Morphological and taxonomic diversity in a clade's history: the blastoid record and stochastic simulations. Contributions from the Museum of Paleontology, University of Michigan, 28:101–140.Google Scholar
Galloway, J. 1990. A handle on handedness. Nature, 346:223–224.Google Scholar
Horowitz, A. S., Able, S., and Strimple, H. L. 1986. Abnormalities in Pentremites Say (Blastoidea) from the Pella Formation (Upper Mississippian) of Iowa. Journal of Paleontology, 60:390–399.CrossRefGoogle Scholar
Lane, N. G., and Webster, G. D. 1967. Symmetry planes of Paleozoic crinoids. University of Kansas Paleontological Contributions, Paper 25:14–16.Google Scholar
Macurda, D. B. Jr. 1978. The Mississippian blastoid genus Cribroblastus . Journal of Paleontology, 52:1288–1293.Google Scholar
Macurda, D. B. Jr. 1980. Abnormalities of the Carboniferous blastoid Pentremites . Journal of Paleontology, 54:1155–1162.Google Scholar
Macurda, D. B. Jr. 1983. Systematics of fissiculate Blastoidea. Papers on Paleontology, Museum of Paleontology, University of Michigan, no. 22:1–291.Google Scholar
Teichert, C. 1949. Permian crinoid Calceolispongia . Geological Society of America Memoir, 34:1–132.Google Scholar
Wanner, J. 1924. Die permischen Echinodermen von Timor, II. Paläontologie von Timor, XIV:1–81.Google Scholar
Wanner, J. 1932. Neue Beiträge zur Kentniss der permischen Echinodermen von Timor, VII. Die Anomalieen der Schizoblasten. Dienst van den Mijnbouw in Nederlandisch-Oost-Indie, Wetenschappelijke Mededeelingen, 20:1–46.Google Scholar
Webster, G. D. 1990. New Permian crinoids from Australia. Palaeontology, 33:49–74.Google Scholar