Fossil snakes are most often identified from isolated vertebrae, complicating estimations of total body lengths of extinct taxa. Here we estimate the range of total body length of the late Eocene North American palaeophiid marine snake Pterosphenus schucherti based on 29 recently collected fossil vertebrae from Wilkinson County, Georgia, USA. Previous research suggests that the palaeophiids are most closely related to modern boids. Total body length estimates here are based on family-specific regressions of centrum length versus known total body length in extant members of Boidae, Pythonidae, and Colubridae. The high correlation coefficients for the family specific regressions supports previous studies that used centrum length to estimate total body length in extinct snakes. Here, size estimates for Pterosphenus schucherti ranged from 2.5 to 4.8 m using boids, 3.4 to 13.0 m using pythonids, and 2.8 to 5.3 m using colubrids. This study demonstrates how the lumping of multiple extant clades greatly increases the range of variability for length estimations. For the TL estimates of fossil snakes, it appears that regressions generated from the lowest taxonomic level of the most closely related extant species should be used.


George Bennett, Patrick Powers, Parker Rhinehart and Heidi Mead assisted in the field collection of the fossil vertebrae. A special thanks to Heidi Mead at Georgia College for her assistance with photography. This manuscript benefited from critical reviews by Heidi Mead and two anonymous reviewers.