Species of Catillicephala are known from sites around the mid-Cambrian margin of Laurentian North America, including Vermont, Quebec, Newfoundland and North Greenland. Catillicephala cifellii sp. nov. is from the Downes Point Member of the Shallow Bay Formation (Cow Head Group) in western Newfoundland. It occurs in three shelf margin-derived boulders in debris flow conglomerates that accumulated in a continental slope setting. The associated trilobites and agnostoid arthropods, including Ptychagnostus aculeatus and Megagnostus glandiformis, indicate a correlation with the Lejopyge laevigata Zone. As such, C. cifellii is among the oldest representatives of the genus, and is early Guzhangian in age.

Key words: Trilobita, Catillicephala, Cambrian, Laurentia, North America.

Stephen R. Westrop [swestrop@ou.edu], Oklahoma Museum of Natural History and School of Geosciences, University of Oklahoma, Norman, OK 73072, USA. Correspondence address: 103 Melita Street, Ingersoll, Ontario N5C 3W3, Canada. Alyce A. Dengler [sandydengler2@yahoo.com], Oklahoma Museum of Natural History, University of Oklahoma, Norman, OK 73072, USA.