Ventral Body Color, Western Ratsnake
Pantherophis obsoletus, the Western Ratsnake (a.k.a., black ratsnake or chicken snake), is a large colubrid species widely distributed throughout the central and southcentral United States west of the Mississippi River (Powell et al. 2016). This species has received considerable attention with its early taxonomic history found in Neill (1949) and Dowling (1952) and its current phylogeographic status examined by Burbrink et al. (2000), Burbrink (2001), and Gibbs et al. (2006). Dorsal body color and pattern played an important role in resolving the early taxonomic issues within this ratsnake species complex, whereas mtDNA was utilized in the more recent phylogeographic analyses of ratsnake groups. As a whole, however, phenotypic plasticity in body color and pattern is a hallmark feature in all North American ratsnake complexes. For example, few species show as much regional variation as do ratsnakes in the southeastern United States (Gibbons and Dorcas 2005).
Trauth, Stanley E.
"Regional Variation in Ventral Body Color and Pattern in the Western Ratsnake, Pantherophis obsoletus (Reptilia: Serpentes: Colubridae), in Arkansas,"
Journal of the Arkansas Academy of Science: Vol. 74
, Article 16.
Available at: https://scholarworks.uark.edu/jaas/vol74/iss1/16