The Morrison Formation - Fossil Ecosystems of North America: A Guide to the Sites and their Extraordinary Biotas - page 146

147

147 The theropod dinosaur Allosaurus fragilisAMNH. Length 12 m 40 ft.

decomposed on dry open land or in
channel beds prior to deposition. After
death the arid climate dehydrated muscle
tissue, ligaments, and skin, but there is
little evidence of scavenging and little sign
of cracking or exfoliation of the bones.
Richmond and Morris (1998) suggested
that they were exposed for no more than
10 years before burial by the flash flood.

148

D ESCRIPTION OF THE M ORRISON
F ORMATION BIOTA
Allosaurus
This was one of the largest predatory
theropod dinosaurs of the Jurassic, up to 12 m
(40 ft) in length and weighing up to 1.5 tons
( 147-149 ). The skull was almost 1 m (3 ft)

148 The skull of Allosaurus fragilis, with
sharp serrated teeth for cutting meat SMA.
Length of skull 1 m 3.3 ft.

149

149 Reconstruction of Allosaurus.