A PARTIAL SKELETON OF GONIOPHOLIS FROM THE BRUSHY BASIN MEMBER OF THE MORRISON FORMATION

A partial skeleton of the crocodyliform Goniopholis (MWC 5534) was found in a channel sandstone in association with a polacanthid ankylosaur at Cactus Park in western Colorado. The specimen consists mostly of natural molds of four vertebrae, a tibia, a partial femur, a partial fibula, several ribs, and 15+ dermal scutes. The specimen is one of less than ten associated skeletons of Goniopholis found in the Morrison Formation so far. Large crocodylomorphs to approximately 3m and 120kg (Goniopholis, Eutretauranosuchus, Macelognathus) are known from at least 45 localities in the Morrison Formation, and 75% of the occurrences are in wet overbank or river channel deposits. An additional 16% of localities containing large crocodylomorphs are pond deposits also containing microvertebrates. The remaining 9% are in splay sands, lacustrine/wetlands, or well-drained floodplains. This evidence, strongly associating them with freshwater environments, suggests the large Morrison crocodylomorphs were indeed as semi-aquatic in habits as are modern crocodilians.