The Early Jurassic ichnogenus Otozoum

Emma C. Rainforth, Dept. of Earth and Enviro. Sci., Columbia Univ., LDEO, Rt. 9W, Palisades NY 10964, emmar@ldeo.columbia.edu
 

    Otozoum moodii is one of the classic Connecticut Valley ichnogenera established by Edward Hitchcock between 1836 and 1865. The type specimen is re-identified (Amherst College 4/1a) and the genus rediagnosed, allowing the two additional currently-valid species to be synonymized with O. moodii. Like Batrachopus, Pseudotetrasauropus (Ellenberger) of southern Africa and the Colorado Plateau shows only 4 phalanges in digit IV, thus distinguishing it from Otozoum, and suggesting a crocodylomorph or rauisuchian trackmaker for these genera. Otozoum is found in the Newark Supergroup of the Fundy, Hartford and Deerfield rift basins, as well as the Navajo Sandstone (Colorado Plateau). Based on the cyclostratigraphy of the Newark Basin, Otozoum is restricted to Early Jurassic strata. It appears to migrate south with time in the Newark Supergroup, perhaps to remain in a single climatic belt.

    Trackmaker identification was undertaken by reconstructing the pes of the trackmaker from the footprint. Using pedal characters of published cladograms, non-dinosaurian archosaurs were precluded, and the trackmaker was identified as a prosauropod, non-genasaurian ornithischian, or non-eurypodid thyreophoran dinosaur. Comparison with skeletons of Early Jurassic dinosaurs suggests Otozoum was probably made by a prosauropod. However, the presence of digits I and V in the footprints suggests that unlike other saurischians, prosauropods held the metatarsus close to the ground whilst walking.
 

Abstracts with Programs, Geological Society of America vol. 32, no. 1, p. 67 (2000)
 

Geological Society of America, P.O. Box 9140, Boulder, CO 80301-9140 USA (http://www.geosociety.org)


Back to Emma's homepage.

This page last updated March 29th, 2002.