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A new arthropod, Meristosoma: More fallout from the Cambrian explosion

Published online by Cambridge University Press:  20 May 2016

R. A. Robison  and
E. O. Wiley
R. A. Robison
Affiliation:
Department of Geology and Department of Systematics and Ecology, University of Kansas, Lawrence 66045
E. O. Wiley
Affiliation:
Department of Geology and Department of Systematics and Ecology, University of Kansas, Lawrence 66045
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Abstract

New Middle Cambrian fossils demonstrate unusual tagmosis within the Arthropoda. Rare specimens from the Spence Shale of northern Utah are assigned to Meristosoma paradoxum n. gen. and sp. One specimen from the Marjum Formation of west-central Utah is assigned to Meristosoma sp. These taxa are further assigned to the new family Meristosomatidae. Meristosoma, which reached 17 cm in length, is characterized by a short anterior shield, a long thorax with 36 or more articulating segments, and a posterior shield with as many as 11 fused segments. Its short anterior shield and long, multisegmented thorax have a myriapodan aspect, but Meristosoma differs from all myriapods by its posterior tagmosis. In dorsal view, its posterior shield is most like that of some macropygous trilobites, but Meristosoma differs from all trilobites by having a shorter anterior shield, ringed thoracic segments without trilobation, and no ventral doublure. Phylogenetic analysis indicates that Meristosoma is a primitive and basal arthropod. A more precise taxonomic assignment is hampered by a lack of information about its limb morphology.

Type
Research Article
Information
Journal of Paleontology , Volume 69 , Issue 3 , May 1995 , pp. 447 - 459
Copyright
Copyright © The Paleontological Society 

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