Dermochelys coriacea: Four Leatherback Turtles found dead on New South Wales beaches.

A Leatherback Turtle, Dermochelys coriacea, was found dead on North Shelly Beach, New South Wales, on Sunday 10 April 2022, bringing the number of these Turtles found dead in the area to four since 27 March. Leatherbacks, which are not typically found in the waters off New South Wales, have also been found on beaches at Toowoon Bay, Avoca, and Birdie. The cause of the strandings is unclear, although the New South Wales National Parks and Wildlife Service has suggested that the Animals may have been blown off course by recent Pacific storms, and then got into trouble in the cooler waters off the southern Australian coast. The Australian Registry for Wildlife Health has collected the Turtles to perform necropsies, which may help to understand what has happened to them.

 

A Leatherback Turtle found dead on North Shelly Beach, New South Wales, on Sunday 10 April 2022. Trinity Peace/ABC News.

Leatherback Turtles are the larges species of Chelonian (Turtles and Tortoises) alive today. and have a distinctive leathery shell which makes them easy to identify. They are placed in a separate family to all other Turtles, the Dermochelyidae, which has no other living species, but a fossil record dating back to the Late Cretaceous. Modern Leatherback Turtles are found in tropical and warm temperate waters in the Atlantic and Pacific Oceans, as well as in the southwest Indian Ocean. They are considered to be Vulnerable under the terms of the International Union for the Conservation of Nature's Red List of Threatened Species, mostly due to a loss of suitable breeding grounds due to Human encroachment; unlike other Turtle species their flesh is generally considered to oily for consumption by Humans, limiting the impact of hunting on the species, although they are vulnerable to being caught as bycatch in fishing nets and becoming entangled in abandoned fishing gear. Other marine plastics are also a significant risk to the species, as items such as plastic bags can resemble Jellyfish, the main diet of these Turtles.

 

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Learthback Turtle found on beach in Essex, England.

A Leatherback Turtle, Dermochelys coriacea, has been discovered on a beach in Essex, southeast England, this week. The Turtle, which is estimated to weigh about 250 kg, was discovered by a Dog-walker on a beach on Mundon Creek, part of the Blackwater River Estuary System, on the morning of Wednesday 11 December 2019. The UK Cetacean Strandings Investigation Programme was called in to investigate the Turtle, and was able to work with the local Coastguard and landowners to recover the body of the animal, for examination at the Natural History Museum in London. Leatherback Turtles are occasionally washed up on the warmer beaches of southwest England and the south coast of Ireland, but have not previously been recorded on the east coast of England, or elsewhere on the North Sea.

The body of a Leatherback Turtle, Dermochelys coriacea, which was recovered on the Essex coast this week. South Woodham Coastguard Rescue Team.

Leatherback Turtles are the larges species of Chelonian (Turtles and Tortoises) alive today. and have a distinctive leathery shell which makes them easy to identify. They are placed in a separate family to all other Turtles, the Dermochelyidae, which has no other living species, but a fossil record dating back to the Late Cretaceous. Modern Leatherback Turtles are found in tropical and warm temperate waters in the Atlantic and Pacific Oceans, as well as in the southwest Indian Ocean. They are considered to be Vulnerable under the terms of the International Union for the Conservation of Nature's Red List of Threatened Species, mostly due to a loss of suitable breeding grounds due to Human encroachment; unlike other Turtle species their flesh is generally considered to oily for consumption by Humans, limiting the impact of hunting on the species, although they are vulnerable to being caught as bycatch in fishing nets and becoming entangled in abandoned fishing gear. Other marine plastics are also a significant risk to the species, as items such as plastic bags can resemble Jellyfish, the main diet of these Turtles.

Leatherback Turtle, Dermochelys coriacea, washed up on a beach in Essex, southeast England, earlier this week. Harwich and Manningtree Standard.

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Leatherback Turtle dies in aquarium after being rescued from rope on Cape Cod, Massachusetts.

A 190 kg Leatherback Turtle, Dermochelys coriacea, has died at a Sea Turtle Hospital in Quincy,  Massachusetts, run by the New England Aquarium, the day after being found entangled in rope on Cape Cod on 31 October 2018. The female animal had been rescued from the rope and treated for an injury to its front flipper, but did not survive the night. It was later found to have swallowed a piece of plastic 28 cm in length and 12 cm in width, which is believed to be the cause of its death.

A female Leatherback Turtle being treated for injuries on 31 October 2018. New England Aquarium.

Leatherback Turtles are more-or-less global in distribution, being found in all the world's oceans except the Arctic and Southern, though this global population is generally considered to be split into a series of subpopulations. The species is currently considered to be Vulnerable under the terms of the International Union for the Conservation of Nature's Red List of Threatened Species, as it has suffered a 40% loss in numbers over the past three generations, due to loss of breeding grounds and encounters with marine litter, particularly floating plastics, which they appear to be incapable of differentiating from Jellyfish, their main prey, and abandoned or lost fishing nets, in which they become entangled.

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A new species of Turtle from the Late Cretaceous of Morocco.

Turtles are aquatic reptiles with a shell that encases their body, and into which the head and limbs can be retracted at least partially. They have a fossil record that dates back to the Late Triassic, about 220 million years ago, and they have been an important part of many marine and freshwater ecosystems ever since. Their exact relationship to other reptiles is difficult to determine from morphological evidence since their bodies have become so heavily modified, but genetic studies suggest that they are a sister group to the Archosaurs (Crocodiles, Dinosaurs and Birds). The Leatherback Turtles, Dermochelyoidae, lack the rigid boney shells of other turtles, instead having a carapace covered by thick oily skin, which has boney plates embedded within it. The living Leatherback (Dermochelys coriacea) is the largest extant Turtle species, reaching around 2.5 m, but it is thought some extinct species may have been even larger.

In a paper published in the journal PLoS One on 11 July 2013, a team of scientists led by Nathalie Bardet of the Département Histoire de la Terre, Muséum National d’Histoire Naturelle describe a new species of Leatherback Turtle from the Late Cretaceous phosphatic deposits of Sidi Chennane in the Oulad Abdoun Basin in central Morocco.

The new species is named Ocepechelon bouyai, where 'Ocepechelon' derives from 'OCP', acronym for the Groupe Office Chérifien des Phosphates, the mining company exploiting phosphatic deposits in Morocco, plus 'chelon', Greek for Turtle, and 'bouyai' honours Baâdi Bouya, head of the OCP Geological Survey in Khouribga.

The species is named from a single skull, excluding the lower mandible. The skull is 70 cm long, suggesting that the complete animal would have been considerably larger than the extant Leatheback Turtle, and has a unique set of features not seen in any other known living or fossil turtle.

Ocepechelon bouyai, right lateral view of the skull. Photograph and interpretative drawing. Abbreviations: En, external nare; Fr, frontal; Ica, incisura columellae auris; Ju, jugal; Mx, maxilla; Na, nasal; Pa, parietal; Pal, palatine; Pfr, prefrontal; Pmx, premaxilla; Po, postorbital; Pt, pterygoid; Q, quadrate; Qj, quadratojugal; Ra, marks of the rhamphotheca; Sq, squamosal. Bardet et al. (2013).

Ocepechelon bouyai has an elongated cylinder shaped snout, resembling a pipette, without any sign of teeth or other food-processing structures, as well as highly developed pterygoid flanges, forming wing-like structures on the sides of its head.

Ocepechelon bouyai, dorsal (left) and ventral (right) views of the skull. Photographs and interpretative drawings. Abbreviations: Boc, basioccipital; Bsph, basisphenoid; Cho, choanae; En, external nare; Fpci, foramen posterior canalis carotici interni; Fr, frontal; Ica, incisura columellae auris; Ju, jugal; Mx, maxilla; Na, nasal; Op, opisthotic; Pa, parietal; Pal, palatine; Pfr, prefrontal; Pmx, premaxilla; Po, postorbital; pr tro ot, processus trochlearis oticus; Pt, pterygoid; Ptw, pterygoid wing; Q, quadrate; Qj, quadratojugal; Ra, marks of the rhamphotheca; Sq, squamosal; Vo, vomer. Bardet et al. (2013).

Bardet et al. interpret these structures to imply Ocepechelon bouyai was a suction feeder, with a feeding technique similar to that seem in Pipefish and Seahorses, but capable of targeting small Fish, Cephalopods (Squid, Octopus, Belemnites etc.) or Jellyfish, and driven by powerful muscles attached to the pterygoid flanges, which could have been used to create a vacuum in the mouth, sucking food in.

Reconstruction of Ocepechelon bouyai as a living animal. C. Letenneur in Bardet et al. (2013).

See also A Geomydid Turtle from the Miocene of Tanegashima Island, Japan, A Jurassic Turtle bone-bed from the far northwest of China, The death of Lonesome George and the extinction of the Pinta Island Giant Tortoise, An Eucryptodiran Turtle from the Early Cretaceous of Spain and A new species of Giant Side-Necked Turtle from the Palaeocene of Columbia.

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