Lepisosteus occidentalis ( Leidy, 1856 )

Sahni, Ashok, 1972, The vertebrate Fauna of the Judith River formation, Montana, Bulletin of the American Museum of Natural History 147 (6), pp. 319-416 : 345

Lepisosteus occidentalis ( Leidy, 1856)

Lepidotus occidentalis LEIDY, 1856, p. 73.

Lepidotus haydeni LEIDY, 1856, p. 73.

Lepisosteus occidentalis : COPE, 1877, p. 574.

Scales and vertebrae of Lepisosteus occidentalis are some of the more common elements of the Judith River fauna. The widespread occurrence of this gar in most of the localities of the Cretaceous and Paleocene of Montana, Wyoming, and adjoining states makes it an excellent marker for microvertebrate localities ( Estes, 1964, p. 43). It closely resembles and probably occupied an ecologic niche similar to that occupied by the large Recent alligator gar, L. spatula , which at present is restricted to the large streams and rivers around the Gulf of Mexico.

Originally described as Lepidotus by Leidy (1856, p. 73), the material was referred to two species, L. occidentalis , on the basis of five scales, and L. haydeni , on a single scale. Later, Cope (1877, p. 574) put L. haydeni in synonymy with L. occidentalis . Reference of other elements of the gar were made from the Hell Creek Formation, Montana, by Brown (1907); Lance Formation, Wyoming, by Williston (1902); and other Upper Cretaceous formations of Colorado by Marsh (1 896b).