found: Standard common and current scientific names for North American amphibians, turtles, reptiles & crocodilians, 2002(Elaphe obsoleta, Western Rat Snake)
found: Center for North Amer. herpetology website, July 12, 2005(Western Rat Snake, Elaphe obsoleta; the name obsoleta is restricted to the newly defined lineage (= species) west of the Mississippi River; thus, the name of the eastern lineage would become Elaphe alleghaniensis; recognition of subspecies of Elaphe obsoleta is unwarranted and is taxonomically misleading; E. obsoleta actually consists of three distinct species; name Elaphe obsoleta is restricted to those populations west of the Mississippi River)
found: NatureServe explorer, via WWW, July 12, 2005(under Elaphe obsoleta: Burbrink et al. (2000) and Burbrink (2001) examined genetic and morphological variation in Elaphe obsoleta and determined that the nominal subspecies do not represent evolutionary lineages and should no longer be recognized; these authors identified three clades within E. obsoleta, corresponding to populations (1) west of the Mississippi River (western clade), (2) east of the Mississippi River and west of the Appalachian Mountains and Apalachicola River (central clade), and (3) east of the Appalachians and the Apalachicola River (eastern clade). Burbrink (2000) recognized the three clades as distinct species: E. obsoleta (western clade), E. spiloides (central clade), and E. alleghaniensis (eastern clade); under Burbrink's arrangement, E. obsoleta would be known as the "western rat snake" (also rendered "western ratsnake"); Utiger et al. (2002) examined mtDNA variation in New World and Old World "Elaphe" and determined that North American rat snakes currently included in the genus Elaphe form a monophyletic limeage that is distinct from Old World snakes that also have been regarded as Elaphe. They resurrected the genus Pantherophis for the rat snakes north of Mexico, including the following species: Pantherophis obsoletus (and P. alleghaniensis and P. spiloides, if one recognizes those taxa as species))
found: Adam M. Mann home page, July 12, 2005(the common Black Ratsnake, Elaphe obsoleta obsoleta, has evolved from separate evolutionary lineages and can no longer be classified under a single species name; distinct morphologic and genetic characteristics separate individuals found in different parts of the eastern United States. Therefore, the Black Ratsnake must now be considered one of three distinct species based on geographical location) Black Ratsnake (Black Ratsnake, Elaphe obsoleta obsoleta; Black Ratsnake must be considered one of three separate species (Elaphe obsoleta, E. spiloides or E. alleghaniensis) based on geographic distribution throughout the eastern United States; A new publication in the Russian Journal of Herpetology has determined that Old and New World ratsnakes are phylogenetically different, requiring a change in genus. The proposed genus name for New World Ratsnakes is Pantherophis, which is resurrected from a previous taxonomic synonym)
found: Smith, M. The Texas rat snake, via Dallas-Ft. Worth Herp. Soc. website, July 12, 2005(For many years the rat snakes in the eastern U.S. have been divided roughly into the black rat snake group (including black, yellow, gray, Everglades, and Texas subspecies), the corn snake group and the fox snakes. Now some recent studies have proposed that the black rat snake group, rather than being several subspecies of Elaphe obsoleta, is really three distinct species. East of the Allegheny Mountains, these snakes would be Elaphe alleghaniensis, the "eastern rat snake." West of the Apalachicola River and east of the Mississippi, they would be Elaphe spiloides, the "midland rat snake" (largely represented by what we have known as the gray rat snake). West of the Mississippi these snakes would be Elaphe obsoleta (no subspecies), the "western rat snake.")
found: Briggler, J. Snakes of Missouri, via WWW, July 12, 2005(Black Rat Snake, Elaphe obsoleta. Local Name: black snake)
