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Sternotherus odoratus.jpg
Common musk turtle, Sternotherus odoratus
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Superfamily: Kinosternoidea
Family: Kinosternidae
Agassiz, 1857[1]


  • Cinosternoidae - Agassiz, 1857
  • Kinosterna - Gray, 1869
  • Kinosternidae - Hay, 1892

The Kinosternidae are a family of mostly small turtles that includes the mud turtles and musk turtles. The family contains 25 species within four genera, but taxonomic reclassification is an ongoing process, so many sources vary on the exact numbers of species and subspecies. They inhabit slow-moving bodies of water, often with soft, muddy bottoms and abundant vegetation.


Most kinosternids are small turtles, 10–15 cm (3.9–5.9 in) in carapace length. The highly domed carapace has a distinct keel down its center. The genus Staurotypus gets much larger, to 30 cm (12 in). Females are generally larger than males, but males have much longer tails. Kinosternids can be black, brown, green, or yellowish in color. Most species do not have shell markings, but some species have radiating black markings on each carapace scute. Some species have distinctive yellow striping along the sides of the head and neck.

The musk turtles are so named because they are capable of releasing a foul-smelling musk from glands under the rear of their shells when disturbed. They are native to North America and South America.


All members of the family are carnivorous, feeding on crustaceans, aquatic insects, mollusks, annelids, amphibians, small fish, and sometimes carrion. Though they still eat vegetation such as aquatic plants. In captivity they can eat red and green leaf lettuce.


Kinosternids lay about four hard-shelled eggs during the late spring and early summer. After hatching, some species overwinter in the subterranean nest, emerging the following spring. Some adults also spend the winter on land, constructing a burrow with a small air hole used on warm days.

Kinosternids contain the only species of turtle known, or at least suspected, to exhibit parental care. Studies of the yellow mud turtle in Nebraska, United States, suggest females sometimes stay with the nest and may urinate on the eggs long after laying, to either keep them moist or to protect them from snake predation (by making them less palatable).[citation needed]

Some kinosternids, particularly those in the genera Claudius and Staurotypus, exhibit genetic sex determination; in Staurotypus this is XY sex determination, and the same is suspected to be true of Claudius as well. Kinosternon and Sternotherus have temperature-dependent sex determination as is typical of turtles.[2][3]


Family Kinosternidae

Additional images[edit]


  1. ^ a b c Rhodin 2011, pp. 000.175–000.178
  2. ^ Badenhorst, Daleen; Stanyon, Roscoe; Engstrom, Tag; Valenzuela, Nicole (2013-03-20). "A ZZ/ZW microchromosome system in the spiny softshell turtle, Apalone spinifera, reveals an intriguing sex chromosome conservation in Trionychidae". Chromosome Research. 21 (2): 137–147. doi:10.1007/s10577-013-9343-2. ISSN 0967-3849. PMID 23512312. S2CID 14434440.
  3. ^ Kawagoshi, Taiki; Uno, Yoshinobu; Nishida, Chizuko; Matsuda, Yoichi (2014-08-14). "The Staurotypus Turtles and Aves Share the Same Origin of Sex Chromosomes but Evolved Different Types of Heterogametic Sex Determination". PLOS ONE. 9 (8): e105315. Bibcode:2014PLoSO...9j5315K. doi:10.1371/journal.pone.0105315. ISSN 1932-6203. PMC 4133349. PMID 25121779.
  4. ^ Asher J. Lichtig; Spencer G. Lucas (2015). "Turtles of the Eocene Huerfano Formation, Raton Basin, Colorado". New Mexico Museum of Natural History and Science Bulletin. 67: 153–160.
  5. ^ Jason R. Bourque (2013). "Fossil Kinosternidae from the Oligocene and Miocene of Florida, USA". In Donald B. Brinkman; Patricia A. Holroyd; James D. Gardner (eds.). Morphology and Evolution of Turtles. Vertebrate Paleobiology and Paleoanthropology. Springer. pp. 459–475. doi:10.1007/978-94-007-4309-0_25. ISBN 978-94-007-4308-3.
  6. ^ Don Brinkman; Martha Carolina Aguillon-Martinez; J. Howard Hutchison; Caleb M. Brown (2016). "Yelmochelys rosarioae gen. et sp. nov., a stem kinosternid (Testudines; Kinosternidae) from the Late Cretaceous of Coahuila, Mexico". PaleoBios. 33: 1–20.