diamondback terrapin

n.
One of several turtles of the genus Malaclemys of the southern Atlantic and Gulf coasts of the United States, having edible flesh and a carapace with diamond-shaped ridged or knobbed markings.

Malaclemys terrapin

SUBFAMILY

Deirochelyinae

TAXONOMY

Testudo terrapin Schoepff, 1793, Philadelphia, Pennsylvania, and Long Island, New York, later restricted by Schmidt (1953, 95) to the coastal waters of Long Island. Seven subspecies are recognized.

OTHER COMMON NAMES

French Malaclémyde terrapin; German: Diamantschildkröte.

PHYSICAL CHARACTERISTICS

A small- to medium-sized turtle (maximum carapace length 9 in [24 cm]) with a rough, slightly keeled carapace and smooth speckled skin. The light brown, gray, or black carapace has raised concentric rings because the scutes are not shed each year, and new larger scutes form below. The rigid plastron varies in color from yellow to black and may have a distinctive pattern of blotches. The color of the soft skin is also quite variable, ranging from black to a light gray with black flecks. The females are much larger than the males and have larger heads with broad crushing plates. There are specialized salt glands near the eyes that excrete excess salt.

DISTRIBUTION

East Coast of temperate North America from southern Texas along the Gulf of Mexico and around Florida to Cape Cod, Massachusetts.

HABITAT

Salt marshes in brackish coastal waters and estuaries.

BEHAVIOR

Normally active during the day, this species may haul out on rocks or the banks of tidal creeks to bask. Terrapins range widely while foraging for food; however, they are often found in the same small area over consecutive years. Adults hibernate communally on the muddy bottom of creek beds. In southern climates the terrapins may become active on warm winter days, but in northern populations they remain in dormancy.

FEEDING ECOLOGY AND DIET

This species is highly specialized to feed upon mollusks. The females develop especially large heads with broad jaws for crushing the shells of marine gastropods. The diet of the smaller males differs from that of the female in that they consume different size classes of gastropods and they may supplement with a variety of aquatic insects.

REPRODUCTIVE BIOLOGY

The female is considerably larger than the male and may therefore choose her mate. In temperate regions, nesting occurs from mid-May to late July, but southern populations may nest as late as September. The females can store sperm in their oviducts for at least four years; however, fertility rates drop precipitously after the second year. The elongate eggs (1.0–1.7 in [26–42 mm] long and 0.6–1.1 in [16–27 mm] wide) have flexible shells. Two or more clutches of up to 20 eggs are deposited annually in the sandy dunes above the winter high tide mark. The eggs hatch after 61 to 104 days of incubation. Sex is dependent upon the incubation temperature; mostly males are produced from 77 to 84°F (25 to 29°C), however at 86°F (30°C) the hatchlings are all female. Most hatchlings emerge in the autumn and are presumed to hibernate aquatically, but some hatchlings may overwinter in the nest.

CONSERVATION STATUS

This species is listed as Lower Risk/Near Threatened on the IUCN Red List. Once considered a delicacy among aristocrats, it was decimated during the early twentieth century by overcollection for human consumption. The terrapin has largely recovered; however, populations continue to be threatened by the destruction and degradation of the tidal marshes they inhabit, and many thousands are needlessly drowned in crab traps that could be made safe by a simple modification.

SIGNIFICANCE TO HUMANS

This species was once prized for its delicate flesh; however, it fortunately fell out of favor with the wealthy. It is still consumed locally and is often sold in the Asian markets of large North American cities.

Note: click on a word meaning below to see its connections and related words.

The noun has one meaning:

Meaning #1: of marshes along Atlantic and Gulf coasts of United States
  Synonym: Malaclemys centrata

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