|Scientific Name:||Pantherophis emoryi (Baird & Girard, 1853)|
Scotophis emoryi Baird & Girard, 1853
|Taxonomic Notes:||Burbrink (2001) used cytochrome b sequences to examine phylogenetic relationships among E. guttata populations (one specimen from each of 53 locations throughout most of the range). He found no support for recognition of the nominal subspecies intermontanus and meahllmorum as distinct taxa; these appear to be junior synonyms of E. guttata emoryi. Burbrink identified three partitions of E. guttata: an eastern partition (east of the Mississippi River) corresponding to E. guttata guttata, a western partition corresponding to E. guttata emoryi (including E. g. intermontanus and E. g. meahllmorum), and a central partition in western Louisiana and eastern Texas. The central partition, in pine and pine-hardwood habitat west of the Mississippi River, clustered closer to the eastern partition than to the western partition. Burbrink recognized the three partitions as species using evolutionary species criteria: (1) Elaphe guttata (Red Corn Snake) (eastern partition ), (2) Elaphe emoryi (Great Plains Rat Snake) (western partition), and (3) Elaphe slowinskii (Slowinski's Corn Snake) (central partition). One specimen (Hidalgo County, Texas) of the central partition (based on cytochrome b characteristics) was located outside the presumed geographic area and habitat identified for other members of that partition. Crother et al. (2003) adopted these changes. Ernst and Ernst (2003) recognized E. emoryi and E. guttata as distinct species, but their manuscript evidently was completed before Burbrink's paper was published; they did not comment on E. slowinskii.
Utiger et al. (2002) examined mtDNA variation in New World and Old World "Elaphe" and determined that North American rat snakes included in the genus Elaphe form a monophyletic lineage 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), P. guttatus, P. emoryi, P. vulpinus, P. gloydi, and P. bairdi. Crother et al. (2003) noted this proposal but did not adopt it, pending further review. Burbrink and Lawson (2007) agreed with Utiger et al. (2002) that these species do not belong in Elaphe, but suggested that the genus Pantherophis might belong in Pituophis. We retain this species in Pantherophis, following Utiger et al. (2002) pending further information on the relationships of these taxa.
|Red List Category & Criteria:||Least Concern ver 3.1|
|Reviewer(s):||Cox, N., Chanson, J.S. & Stuart, S.N. (Global Reptile Assessment Coordinating Team)|
Listed as Least Concern in view of the large and relatively stable extent of occurrence, area of occupancy, number of subpopulations, and population size.
|Range Description:||This species is endemic to the United States. Its range extends from southwestern Illinois, Missouri, southern South Dakota, and southeastern Colorado southward to San Luis Potosi and Veracruz, and through most of Texas, with a disjunct population in eastern Utah and western Colorado (Conant and Collins 1991, Burbrink 2002).|
Native:Mexico; United States
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This species is represented by many subpopulations. Many occurrences appear to have good viability. Adult population size is unknown but presumably exceeds 100,000. This species is relatively common in many parts of its range. Its extent of occurrence, area of occupancy, number of subpopulations, and population size probably are relatively stable or declining at a rate of less than 10% over 10 years or three generations.|
|Current Population Trend:||Stable|
|Habitat and Ecology:||Habitat includes rocky hillsides, meadows, stream courses and river bottoms, canyons and arroyos, barnyards, abandoned houses and ranch buildings, areas near springs, caves (near entrance), and wooded areas. Terrestrial and arboreal.|
|Major Threat(s):||No major threats are known. Locally, habitat destruction has reduced or eliminated some populations, but this species tolerates moderate levels of habitat alteration such as those associated with rural ranching activities.|
|Conservation Actions:||Many occurrences are in protected areas.|
|Citation:||Hammerson, G.A. 2007. Pantherophis emoryi. The IUCN Red List of Threatened Species 2007: e.T63861A12723067.Downloaded on 21 November 2017.|
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