Kinosternon subrubrum
Kinosternon subrubrum
(Eastern Mud Turtle)
Native Transplant
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Kinosternon subrubrum (Bonnaterre, 1789)

Common name: Eastern Mud Turtle

Taxonomy: available through www.itis.govITIS logo

Identification: Kinosternon subrubrum is a small kinosternid (mud turtle) with a carapace (upper shell) length of 70-125 mm (2.75-4.92 in) (Iverson, 1977; Ernst et al., 1994; Conant and Collins, 1998).  Unlike the kinosternid genus Sternotherus, the plastron (lower shell) is relatively large and has two movable hinges rather than one (Conant and Collins, 1998).  The color of the domed, smooth carapace can be brown, olive, yellowish, or black; in juveniles the carapace can have three longitudinal keels (raised ridges) (Iverson, 1977; Conant and Collins, 1998).  The head and neck are generally brown with a variety of lighter colored stripes or mottling (Iverson, 1977).  Unlike other species of Kinosternon, the ninth marginal scute (plate or lamina) does not extend dorsally, and the first vertebral scute does not contact the second marginal (Iverson, 1977; Powell et al., 1998).  Compare this description with some other kinosternid species accounts on this website titled "Kinosternon scorpioides (Linnaeus, 1766)" and "Sternotherus odoratus (Latreille, 1801)."  The three described subspecies (geographic races) of the Eastern Mud Turtle are Kinosternon subrubrum hippocrepis Gray, 1855 (Mississippi Mud Turtle), K. s. steindachneri (Siebenrock, 1906) (Florida Mud Turtle), and K. s. subrubrum (Lacepède, 1788) (Eastern Mud Turtle), are considered full species by some authorities (discussed by Iverson et al., 2000).  The distinguishing features of the subspecies primarily involve small differences in the size and shape of the plastron, and the size of the bridges (the lateral portions of the shell connecting the plastron to the carapace) (Iverson, 1977; Conant and Collins, 1998).  There is a great deal of overlap in the expression of these subtle differences (Iverson, 1977).  Eastern Mud Turtles have been illustrated by numerous authors (Carr, 1952; Smith, 1961; Ernst and Barbour, 1972, 1989; Mount, 1975; Behler and King, 1979; Pritchard, 1979; Martof et al., 1980; Smith and Brodie, 1982; Garrett and Barker, 1987; [Sievert] and Sievert, [1988]; Dundee and Rossman, 1989; Ashton and Ashton, 1991; Carmichael and Williams, 1991; Ernst et al., 1994; Mitchell and Anderson, 1994; Palmer and Braswell, 1995; Conant and Collins, 1998; Powell et al., 1998; Bartlett and Bartlett, 1999a, b; Behler, 1999; Phillips et al., 1999; Johnson, 2000; Hulse et al., 2001; Minton, 2001).

Size: carapace length of 70-125 mm

Native Range: The indigenous range of K. subrubrum extends from Long Island, New York, southward (excluding higher elevations of the Appalachians) to the entire state of Florida and the Gulf Coast, westward through all the Gulf Coast states, northward through the Mississippi Valley including western Tennessee and Kentucky, southern Indiana (isolated colony in northwestern Indiana) and Illinois, extreme southeastern Missouri, Arkansas, and continuing westward through eastern Oklahoma, and eastern and central Texas (Martof, 1956; Smith, 1961; Webb, 1970; Mount, 1975; Stevenson, 1976; Iverson, 1977, 1989, 1992; Martof et al., 1980; Lohoefener and Altig, 1983; Garrett and Barker, 1987; Moler, 1988; [Sievert] and Sievert, [1988]; Carpenter and Krupa, 1989; Dundee and Rossman, 1989; Ashton and Ashton, 1991; Carmichael and Williams, 1991; Gibbons and Semlitsch, 1991; Ernst et al., 1994; Mitchell, 1994; Mitchell and Anderson, 1994; Palmer and Braswell, 1995; Conant and Collins, 1998; Bartlett and Bartlett, 1999a, b; Phillips et al., 1999; Dixon, 2000; Johnson, 2000; King, 2000; Hulse et al., 2001; Minton, 2001). 


Previous reports of Eastern Mud Turtles from Connecticut and the Florida Keys were based upon misidentifications of Sternotherus odoratus and Kinosternon baurii, respectively (Ernst et al., 1994).

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Interactive maps: Point Distribution Maps

Nonindigenous Occurrences: In California, one K. subrubrum (subspecies not given) was collected in the Nature Conservancy Santa Rosa Plateau Preserve near Temecula, Riverside County, in 1993, and another in a canal (drainage ditch) in Kern County, in 1976 (D. Holland, personal communication 1997).


A K. subrubrum was collected from Essex County, northeastern Massachusetts, in 1992 (Cardoza et al., 1993).

Means of Introduction: As with most introduced turtles, the K. subrubrum found in California and Massachusetts are probably released or escaped pets.

Status: Not established.  All known individuals were collected.

Impact of Introduction: Should these semiaquatic omnivores become established, they can potentially impact any ecosystem by feeding on or competing with indigenous fauna (especially mollusks, insects, crustaceans, amphibians, and other turtles).

Remarks: The taxonomy of the Eastern Mud Turtle has been reviewed or summarized by Iverson (1977, 1989, 1991, 1992, 1998) and Iverson et al. (2000).  The literature and natural history of K. subrubrum has been reviewed by Iverson (1977), Frazer et al. (1991), Gibbons and Semlitsch (1991), and Ernst et al. (1994).  Scientific and standard English names follow Crother (2008).


The Eastern Mud Turtle prefers quiet, well-vegetated, shallow waters with soft substrates, often tolerating brackish waters (Ernst et al., 1994; Conant and Collins, 1998).  Although K. subrubrum does not bask often, it is capable of much terrestrial activity, wandering far from water (Gibbons and Semlitsch, 1991; Ernst et al., 1994; Conant and Collins, 1998).  Kinosternon subrubrum is omnivorous but feeds principally upon insects, mollusks, crustaceans, amphibians, carrion, and occasionally fish (Ernst et al., 1994).  While most food consists of aquatic fauna and vegetation, some foraging is done on land (Ernst et al., 1994).  Females annually lay 1-3 clutches, consisting of 1-6 hard-shelled eggs, in well-drained soil often under some sort of terrestrial cover (Iverson, 1979; Frazer et al., 1991; Ernst et al., 1994).

References: (click for full references)

Ashton, R. E., Jr., and P. S. Ashton. 1991. Handbook of Reptiles and Amphibians of Florida. Part Two. Lizards, Turtles & Crocodilians. Revised Second Edition. Windward Publishing, Inc., Miami. 191 pp.

Bartlett, R. D., and P. P. Bartlett. 1999a. A Field Guide to Florida Reptiles and Amphibians. Gulf Publishing Company, Houston. 280 pp.

Bartlett, R. D., and P. D. Bartlett. 1999b. A Field Guide to Texas Reptiles and Amphibians. Gulf Publishing Company, Houston. 331 pp.

Behler, J. L. 1999. National Audubon Society First Field Guide. Reptiles. Scholastic, Inc., New York. 160 pp.

Behler, J. L., and F. W. King. 1979. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, Inc., New York. 743 pp.

Carmichael, P., and W. Williams. 1991. Florida's Fabulous Reptiles and Amphibians. World Publications, Tampa. 120 pp.

Cardoza, J. E., G. S. Jones, T. W. French, and D. B. Halliwell. 1993. Exotic and Translocated Vertebrates of Massachusetts. Fauna of Massachusetts Series 6. Massachusetts Division of Fisheries and Wildlife, Westborough, Massachusetts. 106 pp.

Carpenter, C. C., and J. J. Krupa. 1989. Oklahoma Herpetology. An Annotated Bibliography. University of Oklahoma Press, Norman. 258 pp.

Carr, A. 1952. Handbook of Turtles. The Turtles of the United States, Canada, and Baja California.  Comstock Publishing Associates, Ithaca and London. 542 pp.

Conant, R., and J. T. Collins. 1998. A Field Guide to Reptiles & Amphibians. Eastern and Central North America. Third Edition, Expanded. Houghton Mifflin Company, Boston. 616 pp.

Crother, B.I. (chair). Committee on Standard and English and Scientific Names. 2008. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. Society for the Study of Amphibians and  Reptiles Herpetological Circular. No. 37. iii + 86p.

Dixon, J. R. 2000. Amphibians and Reptiles of Texas. Second Edition. Texas A & M University Press, College Station. 421 pp.

Dundee, H. A., and D. A. Rossman. 1989. The Amphibians and Reptiles of Louisiana. Louisiana State University Press, Baton Rouge and London. 300 pp + unattached erratum.

Ernst, C. H., and R. W. Barbour. 1972. Turtles of the United States and Canada. The University Press of Kentucky, Lexington. 347 pp.

Ernst, C. H., and R. W. Barbour. 1989. Turtles of the World. Smithsonian Institution Press, Washington, D.C. and London. 313 pp.

Ernst, C. H., J. E. Lovich, and R. W. Barbour. 1994. Turtles of the United States and Canada. Smithsonian Institution Press, Washington and London. 578 pp.

Frazer, N. B., J. W. Gibbons, and J. L. Greene. 1991. Life history and demography of the common mud turtle Kinosternon subrubrum in South Carolina, USA. Ecology 72(6):2218-2231.

Garrett, J. M., and D. G. Barker. 1987. A Field Guide to Reptiles and Amphibians of Texas. Texas Monthly Press, Austin. 225 pp.

Gibbons, J. W., and R. D. Semlitsch. 1991. Guide to the Reptiles and Amphibians of the Savannah River Site. The University of Georgia Press, Athens, Georgia, and London. 131 pp.

Holland, D. C. 1997. Personal communication—Herpetologist, Fallbrook, California.

Hulse, A. C., C. J. McCoy, and E. Censky. 2001. Amphibians and Reptiles of Pennsylvania and the Northeast. Comstock Publishing Associates, Ithaca. 419 pp.

Iverson, J. B. 1977. Kinosternon subrubrum. Catalogue of American Amphibians and Reptiles (193):1-4.

Iverson, J. B. 1979. Reproduction and growth of the mud turtle, Kinosternon subrubrum (Reptilia, Testudines, Kinosternidae), in Arkansas. Journal of Herpetology 13(1):105-111.

Iverson, J. [B.] 1989. Kinosternon subrubrum (Lacépède 1788). P. 66. In: F. W. King and R. L. Burke (editors). Crocodilian, Tuatara, and Turtle Species of the World. A Taxonomic and Geographic Reference. The Association of Systematics Collections, Washington, DC. 216 pp.

Iverson, J. B. 1991. Phylogenetic hypotheses for the evolution of modern kinosternine turtles. Herpetological Monographs 5:1-27.

Iverson, J. B. 1992. A Revised Checklist with Distribution Maps of the Turtles of the World. John B. Iverson, Richmond, Indiana. 363 pp.

Iverson, J. B. 1998. Molecules, morphology, and mud turtle phylogenetics (Family Kinosternidae). Chelonian Conservation and Biology 3(1):113-117.

Iverson, J. [B.], P. [A.] Meylan, and M. [E.] Seidel. 2000. Testudines—turtles. Pp. 75-82. In: B. I. Crother (chair), and Committee on Standard English and Scientific Names (editors). Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. Society for the Study of Amphibians and Reptiles Herpetological Circular (29):i-iii, 1-82.

Johnson, T. R. 2000. The Amphibians and Reptiles of Missouri. Revised and Expanded Second Edition. Missouri Department of Conservation, Conservation Commission of the State of Missouri, Jefferson City. 400 pp.

King, F. W. 2000. Florida Museum of Natural History's Checklist of Florida Amphibians and Reptiles [online]. Florida Museum of Natural History, University of Florida, Gainesville. Available on URL:

Lohoefener, R., and R. Altig. 1983. Mississippi herpetology. Mississippi State University Research Center Bulletin (1):i-vi, 1-66.

Martof, B. S. 1956. Amphibians and Reptiles of Georgia. University of Georgia Press, Athens, Georgia. 94 pp.

Martof, B. S., W. M. Palmer, J. R. Bailey, and J. R. Harrison III. 1980. Amphibians and Reptiles of the Carolinas and Virginia. The University of North Carolina Press, Chapel Hill. 264 pp.

Minton, S. A., Jr. 2001. Amphibians & Reptiles of Indiana. Revised Second Edition. Indiana Academy of Science, Indianapolis. 404 pp.

Mitchell, J. C. 1994. The Reptiles of Virginia. Smithsonian Institution Press, Washington and London. 352 pp.

Mitchell, J. C. and J. M. Anderson. 1994. Amphibians and reptiles of Assateague and Chincoteague Islands. Virginia Museum of Natural History Special Publication (2):[i-iv], 1-120.

Moler, P. 1988. A Checklist of Florida's Amphibians and Reptiles. Nongame Wildlife Program, Florida Game and Fresh Water Fish Commission, Tallahassee. 18 pp.

Mount, R. H. 1975. The Reptiles and Amphibians of Alabama. Auburn University Agricultural Experiment Station, Auburn. 347 pp.

Palmer, W. M., and A. L. Braswell.1995. Reptiles of North Carolina. The University of North Carolina Press for North Carolina State Museum of Natural Sciences, Chapel Hill and London. 412 pp.

Phillips, C. A., R. A. Brandon, and E. O. Moll. 1999. Field Guide to Amphibians and Reptiles of Illinois. Illinois Natural History Survey, Champaign, Illinois. 282 pp.

Powell, R., J. T. Collins, and E. D. Hooper, Jr. 1998. A Key to Amphibians & Reptiles of the Continental United States and Canada. University Press of Kansas, Lawrence. 131 pp.

Pritchard, P. C. H. 1979. Encyclopedia of Turtles. T.F.H. Publications, Inc., Neptune, New Jersey. 895 pp.

[Sievert], G., and L. Sievert. [1988]. A Field Guide to Reptiles of Oklahoma. Oklahoma Department of Wildlife Conservation, Oklahoma City. 96 pp.

Smith, H. M., and E. D. Brodie, Jr. 1982. A Guide to Field Identification. Reptiles of North America. Golden Press, New York. 240 pp.

Smith, P. A. 1961. The amphibians and reptiles of Illinois. Illinois Natural History Survey Bulletin 28(1):[i-v], 1-298. (Reprinted 1986.)

Stevenson, H. S. 1976. Vertebrates of Florida. Identification and Distribution. University Presses of Florida, Gainesville. 607 pp.

Webb, R. G. 1970. Reptiles of Oklahoma. University of Oklahoma Press, Norman. 370 pp.

Author: Louis A. Somma, Pam Fuller, and Ann Foster

Revision Date: 10/28/2009

Citation Information:
Louis A. Somma, Pam Fuller, and Ann Foster, 2018, Kinosternon subrubrum (Bonnaterre, 1789): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL,, Revision Date: 10/28/2009, Access Date: 1/16/2018

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.

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Citation information: U.S. Geological Survey. [2018]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [1/16/2018].

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