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Turtles & Tortoises of the United States
There are 7 families of turtles represented in the United States and Canada. These are comprised of 37 Genus with 88 species.
These popular and easily recognized creatures are found in almost every enviroment, aquatic, oceanic, and terrestrial, throughout the tropical and temperate zones. Large land dwelling turtles are often called tortoises, while those that are hard shelled, edible, and aquatic are terrapins. Structurally, turtles are a bizarre group of animals. With their expanded ribs incorporated into a protective shell, the unique placement of limb girdles inside the rib cage, and horny beak instead of teeth, turtles do not appear closely related to other reptiles. Indeed, turtle origins have puzzled palentologists. However, like other reptiles, turtles have dry scaley skin and body temperature that is controlled behaviorally. Whether aquatic or terrestrial, all turtles enjoy basking in the sun.
Without exception, turtles lay eggs. Some small terrestrial species lay as few as 2 or 3 eggs per clutch, whereas sea turtles come ashore to lay several clutches of a hundred or more. Typically, the female digs a hole, deposits her hard shelled eggs into it, then fills the hole with earth before departing. Depending on the species, incubation may take as little as 6 weeks to more than 7 months. The hatchlings must then dig to the surface and, if aquatic, find their way to the water.
Carettochelyidae is a family of cryptodiran turtles belonging to the Trionychia. It contains only a single living species, the pig-nosed turtle (Carettochelys insculpta) native to New Guinea and Northern Australia.
There are 1 species, representing 1 genus, found in the United States.
Chelidae is one of three living families of the turtle suborder Pleurodira, and are commonly called Austro-South American side-neck turtles. The family is distributed in Australia, New Guinea, parts of Indonesia, and throughout most of South America. It is a large family of turtles with a significant fossil history dating back to the Cretaceous.
There are 2 species, representing 2 genus, found in the United States.
Sea Turtles are characterized by heart shaped, scute covered carapaces, paddlelike limbs with one or two claws, with the exception of the leatherback, are the largest living aquatic turtles. They dwell in tropical waters, ranging into temperate zones in the summer.
There are 6 species, representing 5 genus, found along the coasts of the United States.
Snapping Turtles are among the largest of living freshwater species. They are characterized by massive heads with powerful hooked jaws, long tails, relatively small cross shaped plastrons, and carapaces with 12 marginal scutes on each side.
There are 3 species, representing 2 genus, found in the United States, all of which are native to the U.S.
Dermochelyidae is a family of turtles which has seven extinct genera and one extant genus, including the largest living sea turtles.
The majority are found in the eastern United States. These turtles found north of Mexico are small to medium sized turtles with horny scute covered shells, 12 marginal scutes on each side of the carapace, and 6 pairs of scutes on the plastron. The plastron and bridge are well developed. Unlike tortoises, the hind feet are flattened and elongated with some webbing. With the exception of the high domed Terrapenes, most of these turtle's shells are low profile.
There are 46 species, representing 18 genus, found in the United States, 35 species are native to the U.S. and 9 species have been Introduced.
Geoemydidae are turtles of various sizes (from about 4 to 30 inches in length) with often a high degree of sexual dimorphism. They usually have webbed toes, and their pelvic girdles articulate with their plastrons flexibly. Their necks are drawn back vertically. Their carapaces have 24 marginal scutes. The plastron is composed of 12 scutes and has no mesoplastron; the pectoral and abdominal scutes contact the marginal scutes.
There are 6 species, representing 4 genus, found in the United States.
Musk and Mud Turtles can be distinguished by a small, smooth oval shaped carapace bearing 11 marginal scutes on each side. Rear margin of carapace is not serrated, the plastron is single or double hinged with 10 or 11 scutes. Females have short tails, those of males extend well beyond the carapace margin and end in a blunt of spinelike horny nail.
There are 14 species, representing 3 genus, of Mud & Musk turtles found in the United States, 13 species are native to the U.S. and one is Introduced.
Pelomedusidae is a family of freshwater turtles endemic to sub-Saharan Africa, including Madagascar and São Tomè. They range in size from 4.7 to 17.7 inches in carapace length, and are generally roundish in shape. They are unable to fully withdraw their heads into their shells, instead drawing them to the side and folding them beneath the upper edge of their shells, hence are called African side-necked turtles.
There are 1 species, representing 1 genus, found in the United States.
Tortoises are strictly terrestrial. Their hind feet are stumpy and elephantine, the front limbs bear thick hard scales, and lack all webbing. The shell is often dome shaped, and the thick carapace and plastron are united by a well developed bridge.
There are 13 species, representing 6 genus, found in the United States, only 1 genus with 5 species are native to the U.S. and 8 species have been Introduced.
Softshell Turtles are easily identified by a nearly circular, pancakelike carapace covered with a soft leathery skin instead of horny scutes. The feet are paddlelike, fully webbed, and have 3 claws. The snout is tubular, the beak sharp and enclosed in fleshy lips.
There are 6 species, representing 3 genus, found in the United States, 3 species are native to the U.S. and 3 species have been Introdcued.
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