Olive ridley sea turtle

The olive ridley sea turtle (Lepidochelys olivacea), also known as the Pacific ridley sea turtle, is a medium-sized species of sea turtle found in warm and tropical waters, primarily in the Pacific and Indian Oceans.

Description

The olive ridley is a small sea turtle, with an adult carapace length averaging 60 to 70 cm. The heart-shaped carapace is characterized by four pairs of pore-bearing inframarginal scutes on the bridge, two pairs of prefrontals, and up to 9 lateral scutes per side. Olive ridleys are unique in that they can have variable and asymmetrical lateral scute 6 to 8 counts ranging from five to 9 plates on each side, with six to eight being most commonly observed. Each side of the carapace has 12–14 marginal scutes.

The carapace is flattened dorsally and highest anterior to the bridge. It has a medium–sized, broad head that appears triangular from above. The head's concave sides are most obvious on the upper part of the short snout. It has paddle-like forelimbs, each having two anterior claws. The upperparts are grayish green to olive in color, but sometimes appear reddish due to algae growing on the carapace. The bridge and hingeless plastron of an adult varies from greenish white in younger individuals to a creamy yellow in older specimens.

Sea turtle

Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines. There are seven extant species of sea turtles: the green, loggerhead, Kemp's ridley, olive ridley, hawksbill, flatback, and leatherback.

Taxonomy and Evolution

Sea turtles, along with other turtles and tortoises, are part of the order Testudines. All species except the leatherback are in the family Cheloniidae. The leatherback is the only extant member of the family Dermochelyidae.

In general, sea turtles have a more fusiform body plan than their terrestrial or freshwater counterparts. The reduced volume of a fusiform body means sea turtles can not retract their head, legs, and arms into their shells, like other turtles can.

The species are primarily distinguished by their anatomy: for instance, the prefrontal scales on the head, the number of and shape of scutes on the carapace, and the type of inframarginal scutes on the plastron.

The leatherback is the only sea turtle that does not have a hard shell. Instead, it bears a mosaic of bony plates beneath its leathery skin. It is the largest sea turtle, measuring 6 to 9 feet (1.8 to 2.7 m) in length at maturity, and 3 to 5 feet (0.91 to 1.52 m) in width, weighing up to 1,500 pounds (680 kg). Other species are smaller, being mostly 2 to 4 feet (0.61 to 1.22 m) and proportionally narrower.

Ridley sea turtle

Ridley sea turtles (Lepidochelys) are a genus of sea turtle comprising two species: Kemp's ridley sea turtle and the olive ridley sea turtle.

Kemp's ridley sea turtles are currently on the New York and United States lists of endangered species .

Anatomy

Adult ridley sea turtles grow to a length of 51–71 cm (20–28 in). They have a weight of 36–50 kg (79–110 lb). They feed on crabs, fish, cephalopods, clams, and some marine vegetation.

Etymology and taxonomic history

The etymology of "ridley" is a subject of speculation. Prior to being known as ridleys, the French naturalist Bernard Germain de Lacépède referred to the Lepidochelys species as "bastard turtles". Renowned sea turtle conservationist Archie Carr claimed that "ridley" was a common Floridan term.

Conservation

The Kemp's ridley sea turtle's were on the brink of extinction in the 1960s with low numbers of 200 nesting individuals. Due to strict protection laws that protected their nesting sites in Mexico and altered fishing gear to avoid accidental capture of the Kemp's, the Kemp's ridley numbers have increased to estimated 7000–9000 nesting individuals today. The olive ridley sea turtle is considered to have the most abundant numbers today, estimated as 800,000 nesting individuals. The threats to their survival is loss of nesting habitat, direct harvest of the eggs and adults, and getting caught in fishing gear. Protection of the nesting beaches, changes to the fishing gear, and laws against harvesting the adults and eggs have helped the olive ridley sea turtles numbers gradually increase.