Scientific Illustration

theropod:

Relative proportions of forelimb and hind limb in various theropods. Note the extremely reduced forelimbs of Carnotaurus and Tyrannosaurus, in which forelimb length is less than 20% of the hind limb length. Forelimb/hind limb ratio is 46% in Struthiomimus, 61% in Deinonychus, and 96% in Archaeopteryx. This pattern is even more pronounced when phalanges and unguals are included. Carnotaurus modified from Bonaparte, Novas & Coria (1990); Tyrannosaurus modified from Heilmann (1927); Allosaurus after Paul (1987); Sinornithoides modified from Russell & Dong (1993a); Coelophysis, Struthiomimus, Deinonychus, and Archaeopteryx modified from Padian & Chiappe (1997).

From Middleton & Gatesy, 2000