Proganochelys
Encyclopedia
Proganochelys quenstedti is the second oldest turtle
species discovered to date, known only from fossils found in Germany
and Thailand
in strata from the late Triassic
, dating to approximately 210 million years ago. It has several synonyms, including Chelytherium ("Turtle Beast"), Psammochelys ("Sand Turtle"), Stegochelys ("Roof Turtle") and Triassochelys ("Triassic Turtle").
Until 2008, when the 220 million year old Odontochelys
was discovered, Proganochelys was the oldest known turtle species.
and plastron were already in the modern form, although there were additional plates along the margins of the shell, that would have served to protect the legs. Also unlike any modern species of turtle, its long tail had spikes and terminated in a club, its head could not be retracted under the shell, and its neck was protected by small spines. While it had no teeth in its jaws, it did have small denticles on the palate
.
Turtle
Turtles are reptiles of the order Testudines , characterised by a special bony or cartilaginous shell developed from their ribs that acts as a shield...
species discovered to date, known only from fossils found in Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
and Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
in strata from the late Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
, dating to approximately 210 million years ago. It has several synonyms, including Chelytherium ("Turtle Beast"), Psammochelys ("Sand Turtle"), Stegochelys ("Roof Turtle") and Triassochelys ("Triassic Turtle").
Until 2008, when the 220 million year old Odontochelys
Odontochelys
Odontochelys semitestacea is an extinct turtle species, the oldest known one. It is the only known species in the genus Odontochelys and the family Odontochelyidae. O. semitestacea was first described from three 220 million year-old specimens excavated in Triassic deposits in Guizhou,...
was discovered, Proganochelys was the oldest known turtle species.
Palaeobiology
In life it was about 1 metres (3.3 ft) long, its overall appearance resembling modern turtles in many respects: it lacked teeth, likely had a beak, and had the characteristic heavily armored shell formed from bony plates and ribs which fused together into a solid cage around the internal organs. The plates comprising the carapaceCarapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
and plastron were already in the modern form, although there were additional plates along the margins of the shell, that would have served to protect the legs. Also unlike any modern species of turtle, its long tail had spikes and terminated in a club, its head could not be retracted under the shell, and its neck was protected by small spines. While it had no teeth in its jaws, it did have small denticles on the palate
Palate
The palate is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but, in most other tetrapods, the oral and nasal cavities are not truly separate. The palate is divided into two parts, the anterior...
.