THE CENTER FOR NORTH AMERICAN HERPETOLOGY

Reptilia    Squamata (part)    Colubridae  

Western Ratsnake
Pantherophis obsoletus (Say in James, 1822)

SSAR 9th Edition Comments:
 The date of publication is corrected to 1822 based on Neal (2010, Archives of Natural History 37: 28–38). Using genome-scale data, Burbrink et al. (2020, Evolution 75: 260–277) demonstrated support for continued recognition of P. obsoletus and P. bairdi as a sister species, but that the geographic range of P. spiloides extended further east and therefore overlapped with the locality of the type specimen of P. alleghaniensis at the summit of the Blue Ridge in Virginia (see Hillis and Wüster, 2021, Herpetological Review 52: 51–52 and Burbrink et al., 2021, Herpetological Review 53: 537–547). Thus, the former P. spiloides becomes P. alleghaniensis. The former P. alleghaniensis was then found to occupy the range of the former subspecies P. o. quadrivittatus, along the Southeastern Coast and Florida and thus becomes P. quadrivittatus. Suggestions that the ratsnakes P. obsoletus, P. alleghaniensis, and P. quadrivittatus should be considered subspecies of P. obsoletus (Hillis and Wüster, 2021, op. cit.) renders P. obsoletus paraphyletic with respect to the sister species P. bairdi. This, along with evidence showing that all four taxa are distinct lineages, indicates that they should remain at the species rank (Burbrink et al., 2020, op. cit.).

Range maps are based on curated specimens and provided gratis by CNAH.
(Created by Travis W. Taggart; Version: 2023.04.25.09.36.55)
Download GeoJSON polygon range file: - 0.3 MB

Province/State Distribution:
USA: Arkansas Illinois Indiana Iowa Kansas Louisiana Minnesota Missouri Nebraska Oklahoma Texas

First instance(s) of published English names:
Pilot Snake (Coluber obsoletus: Jordan, David Starr. 1876. Manual of the Vertebrates of the Northern United States: Including the District East of the Mississippi River, and North of North Carolina and Tennessee, Exclusive of Marine Species. Jansen, McClurg, and Company, Chicago, Illinois.. 342pp.); Racer (Coluber obsoletus obsoletus: Yarrow, Henry C. 1876. List of Skeletons and Crania in the Section of Comparative Anatomy of the United States Army Medical Museum for use during the International Exhibition of 1876 in Connection with the Representation of the Medical Department U.S. Army. Army Medical Museum, Washington, D. C. pp.); Pilot Black Snake (Coluber obsoletus obsoletus: Yarrow, Henry C. 1876. List of Skeletons and Crania in the Section of Comparative Anatomy of the United States Army Medical Museum for use during the International Exhibition of 1876 in Connection with the Representation of the Medical Department U.S. Army. Army Medical Museum, Washington, D. C. pp.); Pilot Snake (Coluber obsoletus: Jordan, David S. 1878. Manual of the Vertebrates of the Northern United States: Including the District East of the Mississippi River, and North of North Carolina and Tennessee, Exclusive of Marine Species. Second Edition, Revised, and Enlarged. Jansen, McClurg & Company, Chicago. pp.); Racer (Coluber obsoletus: Jordan, David S. 1878. Manual of the Vertebrates of the Northern United States: Including the District East of the Mississippi River, and North of North Carolina and Tennessee, Exclusive of Marine Species. Second Edition, Revised, and Enlarged. Jansen, McClurg & Company, Chicago. pp.); Lindheimer's Snake (Coluber lindheimeri: Yarrow, Henry C. 1882. Check list of North American Reptilia and Batrachia with catalogue of specimens in U. S. National Museum. Bulletin of the United States National Museum (24):1-249); Mountain Black Snake (Coluber obsoletus obsoletus: Yarrow, Henry C. 1882. Check list of North American Reptilia and Batrachia with catalogue of specimens in U. S. National Museum. Bulletin of the United States National Museum (24):1-249); Pilot Snake (Coluber obsoletus obsoletus: Davis, N. S. Jr. and Frank L. Rice. 1883. Descriptive catalogue of North American batrachia and reptilia, found east of Mississippi River. Illinois Natural History Survey Bulletin 1(5):71); Black Snake (Elaphis obsoletus: Garman, H. 1892. A synopsis of the reptiles and amphibians of Illinois. Illinois Laboratory of Natural History Bulletin 3():215-403); Pilot Snake (Elaphis obsoletus: Garman, H. 1892. A synopsis of the reptiles and amphibians of Illinois. Illinois Laboratory of Natural History Bulletin 3():215-403); Pilot Snake (Coluber obsoletus: Cope, Edward D. 1900. The crocodilians, lizards and snakes of North America. Pages 153-1270 in Report of the U. S. National Museum for the Year Ending June 30, 1898 , Washington, D. C. pp.); Mountain Black Snake (Coluber obsoletus: Cope, Edward D. 1900. The crocodilians, lizards and snakes of North America. Pages 153-1270 in Report of the U. S. National Museum for the Year Ending June 30, 1898 , Washington, D. C. pp.); Black Chicken Snake (Coluber obsoletus obsoletus: Beyer, George. 1900. Louisana herpetology. Proceedings of the Louisiana Society of Naturalists 1897-1899():24-46); Red-headed Chicken Snake (Coluber spiloides: Beyer, George. 1900. Louisana herpetology. Proceedings of the Louisiana Society of Naturalists 1897-1899():24-46); Lindheimer's Snake (Coluber obsoletus lindheimeri: Brown, Arthur, E. 1902. Report of the Board of Directors. Pages 5-22 in Thirtieth Annual Report of the Board of Directors of the Zoological Society of Philadelphia. Allen, Lane, and Scott, Philadelphia, Pennsylvania. pp.); Red-headed Coluber (Coluber spiloides: Branson, Edwin B. 1904. Snakes of Kansas. University of Kansas Science Bulletin 2(13):353-430); Black Snake (Elaphe obsoletus: Hurter, Julius. 1911. Herpetology of Missouri. Transactions of the Academy of Science St. Louis 20(5):59-274); Mountain Black Snake (Elaphe obsoletus: Hurter, Julius. 1911. Herpetology of Missouri. Transactions of the Academy of Science St. Louis 20(5):59-274); Pilot Snake (Elaphe obsoletus: Hurter, Julius. 1911. Herpetology of Missouri. Transactions of the Academy of Science St. Louis 20(5):59-274); Rat Snake (Elaphe obsoletus: Hurter, Julius. 1911. Herpetology of Missouri. Transactions of the Academy of Science St. Louis 20(5):59-274); Pilot Blacksnake (Elaphe obsoleta obsoleta: Stejneger, Leonhard H. and Thomas Barbour. 1917. A Checklist of North American Amphibians and Reptiles. Harvard University Press, Cambridge, Massachusetts. pp.); Chicken Snake (Elaphe obsoleta confinis: Strecker, John K., Jr. 1922. An annotated catalogue of the amphibians and reptiles of Bexar County, Texas. Bulletin Scientific Society of San Antonio (4):1-31); Gray Pilot Snake (Elaphe obsoleta confinis: Strecker, John K., Jr. 1922. An annotated catalogue of the amphibians and reptiles of Bexar County, Texas. Bulletin Scientific Society of San Antonio (4):1-31); Lindheimer's Pilot Snake (Elaphe obsoleta lindheimerii: Strecker, John K., Jr. 1922. An annotated catalogue of the amphibians and reptiles of Bexar County, Texas. Bulletin Scientific Society of San Antonio (4):1-31); Emory's Rat Snake (Elaphe laeta: Schmidt, Karl Peterson and D. D. Davis. 1941. Field Book of Snakes of the United States and Canada. C.P. Putnam and Sons, New York. 365pp.); Pilot Black Snake (Elaphe obsoleta obsoleta: Schmidt, Karl Peterson and D. D. Davis. 1941. Field Book of Snakes of the United States and Canada. C.P. Putnam and Sons, New York. 365pp.); Chicken Snake (Elaphe obsoleta: Schmidt, Karl P. 1953. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280pp.); Rat Snake (Elaphe obsoleta: Schmidt, Karl P. 1953. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280pp.); Texas Chicken Snake (Elaphe obsoleta lindheimeri: Schmidt, Karl P. 1953. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280pp.); Black Chicken Snake (Elaphe obsoleta obsoleta: Schmidt, Karl P. 1953. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280pp.); Pilot Black Snake (Elaphe obsoleta obsoleta: Schmidt, Karl P. 1953. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280pp.);

Taxon Links:

  
Catalog of American Amphibians and Reptiles
  
The Reptile Database
  
NatureServe
  
iNaturalist
  
GenBank
  
USGS - Nonindigenous Aquatic Species Database

Selected References:
1822 James, Edwin. Account of an expedition from Pittsburgh to the Rocky Mountains, performed in the years 1819 and ‘20, by order of the Hon. J. C. Calhoun, Sec’y of War: under the command of Major Stephen H. Long. From the notes of Major Long, Mr. T. Say, and other gentlemen of the exploring party. Compiled by Edwin James, botanist and geologist for the expedition. In two vols. – with an atlas. [Volume 1]. Henry Charles Carey and Isaac Lea, Philadelphia, Pennsylvania. 503pp.
1950 Dundee, Harold A. The type locality for Elaphe l. laeta (B. & G.) . Herpetologica 6(2):55
1963 Fitch, Henry S. Natural history of the Black Rat Snake (Elaphe o. obsoleta) in Kansas. Copeia 1963(4):649-658
1972 Baker, Robert J., George A. Mengden, and James J. Bull. Karyotypic studies of thirty-eight species of North American snakes . Copeia 1972(2):257-265
1986 Miller, Larry L. The status of the black rat snake in Sumner County, Kansas Kansas Herpetological Society Newsletter (64):12
1996 Dundee, Harold A. Some reallocations of type localities of reptiles and amphibians described from the Major Stephen H. Long Expedition to the Rocky Mountains, with comments on some of the statements made in the account written by Edwin James.  Tulane Studies in Zoology and Botany 30:75–89
1997 Prior, Kent A. Conservation biology of Black Rat Snakes: Ecological, demographic, and genetic approaches. Dissertation. Carleton University, Ottawa, Ontario. 211pp.
1999 Lardie, Richard L. The subspecific status and western distribution of the Eastern Rat Snake, Elaphe obsoleta, in Oklahoma. Kansas Herpetological Society Newsletter (115):16-17
2000 Burbrink, Frank T. Systematics of the polymorphic North American rat snake (Elaphe obsoleta). Dissertation. Louisiana State University, Baton Rouge. 202pp.
2000 Burbrink, Frank T., Robin Lawson, and Joseph B. Slowinski. Mitochondrial DNA phylogeography of the polytypic North American Rat Snake (Elaphe obsoleta): A critique of the subspecies concept. Evolution 54:2107-2118
2001 Burbrink, Frank T. Systematics of the Eastern Rat Snake complex (Elaphe obsoleta). Herpetological Monographs 15:1-53
2006 Soltis, Douglas E., Ashley B. Morris, Jason S. McLachlan, Paul S. Manos, and Pamela S. Soltis. Comparative phylogeography of unglaciated eastern North America. Molecular Ecology 15(14):4261–4293
2007 Burbrink, Frank T. and Robin Lawson. How and when did Old World ratsnakes disperse into the New World? Molecular Phylogenetics and Evolution 43:173-189
2008 Collins, Joseph T. and Travis W. Taggart. An alternative classification of the New World rat snakes (genus Pantherophis [Reptilia: Squamata: Colubridae]). Journal of Kansas Herpetology (26):16-18
2008 Genoways, Hugh H. and Brett C. Ratcliffe. Engineer Cantonment, Missouri Territory, 1819-1820: America's first biodiversity inventory. Great Plains Research 18(Spring):3-31
2010 Woodman, Neal. History and dating of the publication of the Philadelphia (1822) and London (1823) editions of Edwin James' Account of an expedition from Pittsburgh to the Rocky Mountains. Archives of Natural History 37(1):28-38
2020 Hillis, David M. The detection and naming of geographic variation within species. Herpetological Review 51(1):52-56
2020 Burbrink, Frank T. Marcelo Gehara, Alexander D. McKelvy, and Edward A. Myers. Resolving spatial complexities of hybridization in the context of the gray zone of speciation in North American ratsnakes (Pantherophis obsoletus complex) Evolution 75(2):260–277
2021 Taggart, Travis W. On the type locality of Pantherophis obsoletus. Collinsorum 10(2):3-4
2021 Hillis, David and Wolfgang Wuster. Taxonomy and nomenclature of the Pantherophis obsoletus complex. Herpetological Review 52(1):51–52
2021 Burbrink, Frank T., R. Alexander Pyron, Marcelo Gehara, Alexander D. McKelvy, and Edward A. Myers. The corrected taxonomic history of the North American Ratsnakes (Pantherophis obsoletus Complex), Herpetological Review 53(3):537-547
2022 Hillis, David M. Species, clades, and their relationship to paraphyly and monophyly: Examples from the Pantherophis obsoletus complex. Herpetological Review 53(1):47-53
2023 Burbrink, Frank T., Sean M. Harrington, Dean Bobo, and Edward A. Myers. Considering admixture when producing draft genomes: an example in North American ratsnakes (Pantherophis alleghaniensis/Pantherophis obsoletus) G3 Genes Genomes Genetics 13(10):1-8
2024 Burbrink, Frank T., Edward A. Myers, R. Alexander Pyron. Understanding species limits through the formation of phylogeographic lineages. Ecology and Evolution 14(10):1-18

THE CENTER FOR NORTH AMERICAN HERPETOLOGY — Accessed: Saturday 26 April 2025 23:44 CT