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Notchpeakia, a new genus of Upper Cambrian (Sunwaptan) “entomaspidid” trilobites

Published online by Cambridge University Press:  14 July 2015

Jonathan M. Adrain
Affiliation:
Department of Geoscience, University of Iowa, 121 Trowbridge Hall, Iowa City 52242,
Stephen R. Westrop
Affiliation:
Oklahoma Museum of Natural History and School of Geology and Geophysics, University of Oklahoma, 2401 Chautauqua Avenue, Norman 73072,

Abstract

Trilobites previously assigned to the Entomaspididae Ulrich in Bridge, 1931 are common in Laurentian strata assigned to the upper Sunwaptan Stage of the Upper Cambrian. Most species are poorly known, and typically only sparse cranidial data are available. Large silicified samples from the Lava Dam Member of the Notch Peak Formation, western Utah, contain three new species for which cranidia, librigenae, thoracic segments, and pygidia are known. the species permit clarification of the morphology and affinities of previously described taxa from elsewhere. They are referred to Notchpeakia n. gen. (type species: N. milleri n. sp.) which, in addition to the type includes N. taylori n. sp., N. notchpeakensis n. sp., N. cherrycreekensis n. sp., and N. varga (Westrop, 1986). the “entomaspidid” trilobites are assigned to the traditionally post-Cambrian Harpetidae Hawle and Corda, 1847.

Type
Research Article
Copyright
Copyright © The Paleontological Society 

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