Skip to main content Accessibility help

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

  • Jonathan M. Adrain (a1) and Stephen R. Westrop (a2)


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.



Hide All
Adrain, J. M., and Westrop, S. R. 2004. A Late Cambrian (Sunwaptan) silicified trilobite fauna from Nevada. Bulletins of American Paleontology, 365, 51 p.
Adrain, J. M., and Westrop, S. R. 2005. Late Cambrian ptychaspidid trilobites from western Utah: Implications for trilobite systematics and biostratigraphy. Geological Magazine, 142:377398.
Bridge, J. 1931. Geology of the Eminence and Cardareva quadrangles. Missouri Bureau of Geology and Mines, second series, 24:1228. (For 1930)
Chatterton, B. D. E., and Ludvigsen, R. 1976. Silicified Middle Ordovician trilobites from the South Nahanni River area, District of Mackenzie, Canada. Palaeontographica Abteilung A, 154:1106.
Ebach, M. C., and McNamara, K. J. 2002. A systematic revision of the family Harpetidae (Trilobita). Records of the Western Australian Museum, 21:235267.
Fortey, R. A. 1983. Cambrian–Ordovician trilobites from the boundary beds in western Newfoundland and their phylogenetic significance. Special Papers in Palaeontology, 30:179211.
Gilman Clark, M., and Shaw, A. B. 1968. Paleontology of northwestern Vermont XVI. Trilobites of the Upper Cambrian Gorge Formation (upper bed 3). Journal of Paleontology, 42:10141026.
Hawle, I., and Corda, A. J. C. 1847. Prodrom einer Monographie der Böhmischen Trilobiten. J. G. Calve, Prague, 176 p.
Hintze, L. F., Taylor, M. E., and Miller, J. F. 1988. Upper Cambrian–Lower Ordovician Notch Peak Formation in western Utah. United States Geological Survey Professional Paper, 1393, 30 p.
Hupé, P. 1953. Classe des Trilobites, p. 44246. In Piveteau, J. (ed.), Traité de Paléontologie. Tome 3. Les Formes Ultimes d'Invertébrés. Morphologie et Évolution. Onycophores. Arthropodes. Échinoderms. Stomocordés. Masson et Cie, Paris.
Hupé, P. 1955. Classification des Trilobites. Annales de Paléontologie, 41:111345.
Jell, P. A., and Adrain, J. M. 2003. Available generic names for trilobites. Memoirs of the Queensland Museum, 48:331553.
Kindle, C. H. 1982. The C.H. Kindle Collection: Middle Cambrian to Lower Ordovician trilobites from the Cow Head Group, western Newfoundland. Geological Survey of Canada Paper, 82-1C:117.
Loch, J. D., Stitt, J. H., and Derby, J. R. 1993. Cambrian–Ordovician boundary interval extinctions: Implications of revised trilobite and brachiopod data from Mount Wilson, Alberta, Canada. Journal of Paleontology, 67:497517.
Ludvigsen, R. 1982. Upper Cambrian and Lower Ordovician trilobite biostratigraphy of the Rabbitkettle Formation, western District of Mackenzie. Royal Ontario Museum Life Sciences Contributions, 134:1188.
Ludvigsen, R., Westrop, S. R., and Kindle, C. H. 1989. Sunwaptan (Upper Cambrian) trilobites of the Cow Head Group, western Newfoundland, Canada. Palaeontographica Canadiana, 6:1175.
Miller, J. F., Evans, K. R., Loch, J. D., Ethington, R. L., and Stitt, J. H. 2001. New lithostratigraphic units in the Notch Peak and House formations (Cambrian–Ordovician), Ibex area, western Millard County, Utah. Brigham Young University Geology Studies, 46:3569.
Rasetti, F. 1944. Upper Cambrian trilobites from the Lévis Conglomerate. Journal of Paleontology, 18:229258.
Rasetti, F. 1952. Cephalic sutures in the Upper Cambrian trilobite Entomaspis . Journal of Paleontology, 26:797802.
Rasetti, F. 1959. Trempealeauian trilobites from the Conococheague, Frederick and Grove limestones of the central Appalachians. Journal of Paleontology, 33:375399.
Rasetti, F. 1961. Dresbachian and Franconian trilobites of the Conococheague and Frederick limestones of the central Appalachians. Journal of Paleontology, 35:104124.
Raymond, P. E. 1937. Upper Cambrian and Lower Ordovician Trilobita and Ostracoda from Vermont. Geological Society of America Bulletin, 48:10791146.
Ross, R. J. Jr. 1951. Stratigraphy of the Garden City Formation in northeastern Utah, and its trilobite faunas. Peabody Museum of Natural History, Yale University, Bulletin, 6:1161.
Stitt, J. H. 1971. Late Cambrian and earliest Ordovician trilobites, Timbered Hills and lower Arbuckle groups, western Arbuckle Mountains, Murray County, Oklahoma. Oklahoma Geological Survey Bulletin, 110:183.
Stubblefield, C. J. 1959. Evolution in trilobites. An address to the Geological Society of London at its anniversary meeting on 29 April 1959. Quarterly Journal of the Geological Society of London, 115:145162.
Taylor, M. E., and Halley, R. B. 1974. Systematics, environment and biogeography of some Late Cambrian and Early Ordovician trilobites from eastern New York State. United States Geological Survey Professional Paper, 834:138.
Walcott, C. D. 1925. Cambrian geology and paleontology, V. No. 3-Cambrian and Lower Ozarkian trilobites. Smithsonian Miscellaneous Collections, 75(3):61146.
Westrop, S. R. 1986. Trilobites of the Upper Cambrian Sunwaptan Stage, southern Canadian Rocky Mountains, Alberta. Palaeontographica Canadiana, 3:1179.
Westrop, S. R. 1995. Sunwaptan and Ibexian (Upper Cambrian–Lower Ordovician) trilobites of the Rabbitkettle Formation, Mountain River region, northern Mackenzie Mountains, northwest Canada. Palaeontographica Canadiana, 12:175.
Whittington, H. B. 1981. Paedomorphosis and cryptogenesis in trilobites. Geological Magazine, 118:591602.
Wiley, E. O. 1981. Phylogenetics: The Theory and Practice of Phylogenetic Systematics. Wiley, New York, 456 p.
Winston, D., and Nicholls, H. 1967. Late Cambrian and early Ordovician faunas from the Wilberns Formation of central Texas. Journal of Paleontology, 41:6696.

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

  • Jonathan M. Adrain (a1) and Stephen R. Westrop (a2)


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.