New body mass estimates for Omomys carteri, a middle Eocene primate from North America

We report new body mass estimates for the North American Eocene primate Omo mys carteri. These estimates are based on postcranial measurements and a va riety of analytical methods, including bivariate regression, multiple regre ssion, and principal components analysis (PCA). All body mass estimation eq uations show high coefficients of determination (R-2), and some equations e xhibit low prediction errors in accuracy tests involving extant species of body size similar to O. carteri. Equations derived from PCA-summarized data and multiple regression generally perform better than those based on singl e variables. The consensus of estimates and their statistics suggests a bod y mass range of 170-290 g. This range is similar to previous estimates for this species based on first molar area (C) 1999 Wiley-Liss, Inc.