Jurassic fishes from the western United States, with comments on Jurassic fish distribution. American Museum novitates ; no. 2796

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New York, N.Y. : American Museum of Natural History
"Seven genera of fishes from the Jurassic (Upper Bathonian-Callovian) Sundance and Wanakah formations of western United States are described and their relationships discussed together with a review of their stratigraphic occurrence. The assemblage includes isolated teeth of the chondrichthyans Hybodus sp. and Ischyodus sp., in part from unrecorded Sundance localities near Hulett, Wyoming. Most common is the generalized neopterygian Hulettia americans (Eastman), new genus of unknown relationship, which occurs in the Sundance of Montana and Wyoming, and in the Wanakah of Colorado (including the Pony Express Limestone) and New Mexico (Todilto Limestone). Lepidotes sp. and Caturus dartoni (Eastman), which belong to a monophyletic species group within the genus Caturus, are both present in the Sundance and the Wanakah. Occithrissops willsoni, new genus, new species from the Sundance, is an ichthyodectiform teleost, but not assignable to suborder. Todiltia schoewei (Dunkle), new genus from the Wanakah, is a teleost compared with Ascalabos and Leptolepis, but its affinities remain unknown. The problem of incertae sedis genera and species (e.g., the monotypic Hulettia) is discussed in regard to identification and relationships of Jurassic fishes from other parts of the world. Included tables and paleogeographic maps show temporal and spatial distribution of these fishes, but variable preservation, inadequate description, and superficial systematic analysis usually preclude detailed comparisons of Jurassic taxa from the literature. It is probable, however, that most Jurassic fish assemblages, like those of the Sundance-Wanakah, are mixtures of form genera and monotypic genera whose relationships are imprecisely known"--P. 2.
86 p. : ill., maps ; 26 cm.
Includes bibliographical references (p. 80-86).