Hostname: page-component-78c5997874-ndw9j Total loading time: 0 Render date: 2024-11-10T02:47:31.670Z Has data issue: false hasContentIssue false
  • English
  • Français

Circumocular suture and visual surface of “Cedaria” woosteri (Trilobita, Late Cambrian) from the Eau Claire Formation, Wisconsin

Published online by Cambridge University Press:  20 May 2016

Nigel C. Hughes ,
Gerald O. Gunderson  and
Michael J. Weedon
Nigel C. Hughes
Affiliation:
Geier Collections and Research Center, Cincinnati Museum Center, 1720 Gilbert Avenue
Gerald O. Gunderson
Affiliation:
Cincinnati, Ohio 45202, 6413 Elmwood Avenue, Middleton, Wisconsin 53562
Michael J. Weedon
Affiliation:
Department of Palaeontology, Natural History Museum, Cromwell Road, London, SW7 5BD, U.K.
Get access Rights & Permissions [Opens in a new window]

Abstract

Rare specimens of the Late Cambrian primitive libristomate trilobite “Cedaria” woosteri from the Eau Claire Formation of north-central Wisconsin preserve an unusual and new ocular suture, and the impressions of lens facets. The suture is circumocular, but loops abaxially onto the ocular platform. The portion of the ocular platform that is enclosed by this suture and is fused with the visual surface is here termed the “ocular plate”. The size and arrangement of the lens facets show that “C.” woosteri possessed a holochroal eye, typical of that known in other Cambrian libristomate trilobites. This nearshore assemblage, while low in diversity, contains a disparate array of trilobite morphotypes.

Type
Research Article
Information
Journal of Paleontology , Volume 71 , Issue 1 , January 1997 , pp. 103 - 107
Copyright
Copyright © The Paleontological Society 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Clarkson, E. N. K. 1966. Schizochroal eyes and vision in some phacopid trilobites. Palaeontology, 9:464–487.Google Scholar
Clarkson, E. N. K. 1973a. Morphology and evolution of the eye in Upper Cambrian Olenidae (Trilobita). Palaeontology, 16:735–763.Google Scholar
Clarkson, E. N. K. 1973b. The eyes of Asaphus raniceps Dalman (Trilobita). Palaeontology, 16:425–444.Google Scholar
Clarkson, E. N. K. 1975. The evolution of the eye in trilobites. Fossils and Strata, 4:7–31.Google Scholar
Clarkson, E. N. K. 1979. The visual system in trilobites. Palaeontology, 22:1–22.Google Scholar
Deer, W. A., Howie, R. A., and Zussman, J. 1966. An introduction to rock-forming minerals. Longman Press, London. 528 p.Google Scholar
Droser, M. L., and Bottjer, D. J. 1986. A semiquantitative field classification of ichnofabric. Journal of Sedimentary Petrology, 56:558–559.Google Scholar
Hughes, N. C. 1994. Ontogeny, intraspecific variation, and systematics of the Late Cambrian trilobite Dikelocephalus. Smithsonian Contributions to Paleobiology, 79:1–89.CrossRefGoogle Scholar
Jablonski, D., and Bottjer, D. J. 1990. The ecology of evolutionary innovation: The fossil record, p. 253–288, In Nitecki, M. H. (ed.), Evolutionary Innovations. University of Chicago Press, Chicago.Google Scholar
Jell, P. A. 1975. The abathochroal eye of Pagetia, a new type of trilobite eye. Fossils and Strata, 4:33–43.CrossRefGoogle Scholar
Ludvigsen, R., and Westrop, S. R. 1985. Three new Upper Cambrian stages for North America. Geology, 13:139–143.Google Scholar
Öpik, A. A. 1967. The Mindyallan fauna of north-western Queensland. Bureau of Mineral Resources, Geology and Geophysics Bulletin, 74(1), 404 p.Google Scholar
Palmer, A. R. 1962. Glyptagnostus and associated trilobites in the United States. U. S. Geological Survey Professional Papers, 374-F:1–49.Google Scholar
Pratt, B. R. 1992. Trilobites of the Marjuman and Steptoean stages (Upper Cambrian), Rabbitkettle Formation, southern Mackenzie Mountains, northwest Canada. Palaeontographica Canadiana, 9:1–179.Google Scholar
Raasch, G. O. 1939. Cambrian Merostomata. Geological Society of America Special Papers, 19:1–146.Google Scholar
Rasetti, F. 1948. Cephalic sutures in Loganopeltoides and the origin of “hypoparian” trilobites. Journal of Paleontology, 22:25–29.Google Scholar
Zhang, X.-G., and Clarkson, E. N. K. 1990. The eyes of Lower Cambrian eodiscid trilobites. Palaeontology, 33:911–932.Google Scholar
Zhang, X.-G., and Clarkson, E. N. K. 1993. Ontogeny of the eodiscid trilobite Shizhudiscus longquanensis from the Lower Cambrian of China. Palaeontology, 36:785–806.Google Scholar