Taxonomy
In recent years there has been some taxonomic controversy over the genus of North American rat snakes. Based on mitochondrial DNA, Utiger et al. (2002) showed that North American Rat Snakes of the genus Elaphe along with closely related genera such as Pituophis and Lampropeltis form a monophyletic group separate from Old World members of the genus. They therefore suggested the resurrection of the available name Pantherophis Fitzinger for all North American taxa (north of Mexico).
All published taxonomy remains a taxonomic suggestion until ruled on by the International Commission on Zoological Nomenclature (ICZN - http://www.iczn.org/), but the body has so far not supported the change and has not addressed the taxonomic suggestion, thus the official taxonomy remains Elaphe.
Crother et al. (2003) rejected the taxonomic change to Pantherophis, preferring to retain the current concept of Elaphe and the spelling obsoleta.
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