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.
- Kingdom: Animalia
- Phylum: Chordata
- Class: Reptilia
- Order: Testudines
- Suborder: Cryptodira
- Superfamily: Kinosternoidea
- Family: Kinosternidae
Within their ranges, these turtles can be found in nearly any freshwater aquatic system. Because of their relatively poor swimming ability, they prefer slow-moving or still waters. However, some species inhabit highly seasonal ephemeral ponds which may only contain water for a few months of each year.
The family Kinosternidae consists of two genera and twenty three species. Four species belong to the genus Sternotherus (musk turtles), and nineteen belong to the genus Kinosternon (mud turtles). The family Kinosternidae is distributed from southeastern Canada to the United States east of the Rockies and southward to Brazil. These are small turtles, with the largest species in Texas achieving a maximum length close to 7 inches (17.8 cm).
All members of the family are carnivorous, feeding on crustaceans, aquatic insects, mollusks, annelids, amphibians, small fish, and sometimes carrion.
In seasonal environments (high latitude or deserts), these turtles have short annual activity periods (three months or less in some cases) and spend the rest of the year hibernating or estivating underground. In wetter, more tropical habitats, they are active year-round. Most are highly aquatic, rarely leaving the water except to nest, although a few species may spend considerable time foraging terrestrially.
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.
Sternotherus odoratus (stinkpot or common musk turtle) derives is common name from its cloacal secretions; it grows to 14 cm, lives on the bottom of ponds and sluggish streams, and is rarely seen on land. There are 20 species in the family, occurring in the New World. “Kinosternidae.”