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Reptilia    Testudines    Kinosternidae  

Mississippi Mud Turtle
Kinosternon hippocrepis Gray, 1856
KY-no-ster-non — hip-oh-KREP-iss

SSAR 9th Edition Comments:
 'Gray, 1855' '(Gray, 1855)' [Catalogue of shield reptiles in the collection of the British Museum. Part I. Testudinata (Tortoises). Taylor and Francis, London, England] was listed as the authority in previous editions of this list. That publication didn't appear until 8 March 1856 (Webb, 1995, Chelonian Conservation and Biology 1: 322–32). Gray (1856, Proceedings of the Zoological Society of London 1855: 197–202) was published on 5 February 1856 (Webb, op. cit.), and therefore has priority. Iverson et al. (2013, Molecular Phylogenetics and Evolution 69: 929–939) supports the species-level recognition hippocrepis. Bourque (2016, Journal of Paleontology 89: 821-844) elevated this taxon to species status. However, Turtle Taxonomy Working Group (2021, Chelonian Research Monographs (8): 1–472) did not follow that recommendation pending additional research. Hurtado-Gómez et al. (2024, Molecular Phylogenetics and Evolution 197: 1–19) supported the elevation of K. s. subrubrum and K. s. hippocrepis (noting a divergence time of more than 11 million years and paraphyly) but stopped short of making that declaration formally. (Taggart, Travis W. and John Carr. 2025. Testudines – Turtles. Pages 55-63 in Kirsten E. Nicholson (Editor), Scientific and Standard English Names of Amphibians and Reptiles of North America North of Mexico, with Comments Regarding Confidence in Our Understanding, 9th Edition. Society for the Study of Amphibians and Reptiles, Lawrence, Kansas. 87 pp.)
Errata/Changes: “Gray, 1855” [Catalogue of shield reptiles in the collection of the British Museum. Part I. Testudinata (Tortoises). Taylor and Francis, London, England] was listed as the authority in previous editions of this list. That publication did not appear until 8 March 1856 (Webb, 1995, Chelonian Conservation and Biology 1: 322–332). Gray (1856, Proceedings of the Zoological Society of London 1855: 197–202) was published on 5 February 1856 (Webb, op. cit.) and therefore has priority. Iverson et al. (2013, Molecular Phylogenetics and Evolution 69: 929–939) supported species-level recognition of K. hippocrepis, and Bourque (2016, Journal of Paleontology 89: 821–844) elevated it to species status. Hurtado-Gómez et al. (2024, Molecular Phylogenetics and Evolution 197: 1–19) reported more than 11 million years of divergence and paraphyly within K. subrubrum sensu lato, supporting the recognition of K. hippocrepis as a distinct species but stopping short of formally proposing the change. Reid et al. (2025, Zoological Journal of the Linnean Society 205: zlaf156), using genomic and morphological data, confirmed a deep divergence corresponding with the Mississippi River Basin and found the western group distinguishable from taxa east of the Mississippi based on multiple morphological characters. They proposed restoring K. hippocrepis to species status, a treatment followed here. — (8/3/2026)

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Occurrences:; 3,613 Total; 2,282 Museum; 1,331 Other
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Province/State Distribution:
United States: Arkansas Illinois Kentucky Louisiana Mississippi Missouri Oklahoma Tennessee Texas

Taxonomic Etymology:
Named for its slightly reddish tone.
Kinosternon — From Greek for “moving chest.”
hippocrepis — Greek hippos = “horse” + krepis = “shoe,” meaning “horseshoe,” referring to the head-stripe pattern.

First instance(s) of published English names:
No historic English names have been assigned to this taxon yet.

Taxon Links:

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

Selected References:
1856 Gray, John E. Catalogue of shield reptiles in the collection of the British Museum. Part I. Testudinata (Tortoises). Taylor and Francis, London, England. 79pp.
1856 Gray, John E. On some new species freshwater tortoises from North America, Ceylon and Australia. The Annals and Magazine of Natural History; Zoology, Botany, and Geology 18(2):263-268
1856 Gray, John E. On some new species of freshwater tortoises from North America, Ceylon and Australia, in the collection of the British Museum. Proceedings of the Zoological Society of London 1855(23):197-202
1995 Webb, Robert G. Date of publication of Gray's Catalogue of Shield Reptiles. Chelonian Conservation and Biology 1(4):322-323
1997 Starkey, David E. Molecular systematics and biogeography of the New World turtle genera Trachemys and Kinosternon. Dissertation. Texas A&M, College Station, Texas.. 149pp.
2013 Iverson, John B., Minh Le, and Colleen Ingram. Molecular phylogenetics of the mud and musk turtle family Kinosternidae. Molecular Phylogenetics and Evolution 69:929-939
2016 Bourque, Jason R. New mud turtles (Kinosternidae, Kinosternon) from the middle-late Miocene of the United States. Journal of Paleontology 89:821-844.
2021 Rhodin, Anders G. J., John B. Iverson, Roger Bour, Uwe Fritz, Arthur Georges, H. Bradley Shaffer, and Peter Paul van Dijk. Turtles and tortoises of the world during the rise and global spread of humanity: First checklist and review of extinct pleistocene and holocene chelonians. Chelonian Research Monographs (8):1-472
2024 Hurtado-Gómez, Juan Pablo, Mario Vargas-Ramírez, John B. Iverson, Walter G. Joyce, James R. McCranie, Claudia Paetzold, and Uwe Fritz. Diversity and biogeography of South American mud turtles elucidated by multilocus DNA sequencing (Testudines: Kinosternidae). Molecular Phylogenetics and Evolution 197(108083):1-19
2025 Reid, Brendan N., Hanh T. Ngo, Tinh H. Nguyen, and John B Iverson. Integrated phylogenetic analysis of south-eastern mud turtles (Kinosternon) using genomic data and morphology supports deep divergence and species status for the Mississippi Mud Turtle (Kinosternon hippocrepis Gray, 1856). Zoological Journal of the Linnean Society 205(3):zlaf156

THE CENTER FOR NORTH AMERICAN HERPETOLOGY — Accessed: Monday 10 August 2026 02:57 CT