Spiny Softshell

Trionyx spiniferus

Spiny Softshell

SPSO

Status

The Spiny Softshell is uncommon to common rangewide although at certain locations it is locally common. North Carolina lists this turtle as a species of special concern.

Description

The Spiny Softshell is a medium-sized to large (12–47 cm) turtle with a flat, leathery carapace that has a sandpaper-like surface. The carapace, head, and limbs are olive, gray, or tan with a pattern of spots or blotches. It has a snorkel-like nose and two stripes on each side of the head. Six subspecies have been described: asperus, emoryi, guadalupensis, hartwegi, pallidus, and spiniferus.

Distribution

Trionyx spiniferus is found from northwestern Vermont to Montana in the north, and southward to the Gulf Coast states and New Mexico (except peninsular Florida and the eastern seaboard). It also occurs in the Colorado River system of California, Nevada, Arizona, and New Mexico.

Habitat

The Spiny Softshell Turtle is highly aquatic. It inhabits creeks, large, swift-flowing rivers, bayous, oxbows, lakes, and impoundments (Ernst and Barbour 1972). Important components of its habitat include sand bars, mud flats, and a soft bottom with some aquatic vegetation. Logs which have fallen in the water provide excellent basking sites.

Special Requirements

The Spiny Softshell requires a soft-bottomed body of water with some aquatic vegetation (Ernst and Barbour 1972).

Breeding Habits

Mating takes place in April or May. Nesting may extend from May to August, with June being the peak month. Clutches of 4–32 eggs are laid in nests excavated in sand banks near water. Hatching occurs from late August until October, with some hatchlings overwintering in the nest.

Food Habits

It eats crayfish, insects, mollusks, worms, tadpoles, and fish.

Remarks

Recently Collins (1990) and Conant and Collins (1991) have followed Maylen’s (1987) classification scheme which subdivided the genus Trionyx into nine genera including the genus Apalone. Webb (1990) thought Meylen’s change premature and that the taxon needs more research. Ernst and others (1994) also chose not to recognize the change from Trionyx to Apalone for the southeastern softshells.

Management Suggestions

Trionyx spiniferus management practices should include the prevention of water pollution and the retention of sand bars, mud flats and soft bottom substrates.

Additional References

Webb 1962, 1973; Mount 1975.