Trionychidae

The tortoises of the family of the trionychidés ( Trionychidae ) have a carapace soft glaze of a thick leather. The family indexes 25 species primarily carnivorous. The family of triasochelydés exists since the beginning of the Trias.

Description

The Hyoplastron and Hypoplastron are distinct. There are no femoral valves. Osseous surface is dug of Cupule S or vermiculations or of the furrows separated by pads, laid out radiairement and concentrically to leave and around a specific center or an axis.

The neurales have Cupule S in " nest of abeille" , or aligned, irregularly, or radiairement starting from the center of the plate.

Certain tortoises can absorb the air by their skin. Trionychidés can absorb for them in water up to 70% their requirements in Dioxygène.

Behavior

These tortoises with soft carapace are probably the first tortoises to have begun again an aquatic life to live in muddy or sandy water not very deep. For that they thus had to undergo physical and behavioral transformations. Their carapace was flattened, round, their osseous structure was reduced, the scales disappeared to leave room to leather. Their carapace does not have peripheral bones (except for the Lissemys ). Their legs provided with three characteristic fingers griffus to their family, are webbed, their neck became extensible and the nostrils were perched at the end of a species of small horn. Moreover, being protected by a hard carapace like the other tortoises, they developed a great aggressiveness.

Kind

The family of the Trionychidés includes/understands the following kinds of tortoises répartient into two:
  • the Cyclanorbinae subfamily:
    • Cyclanorbis Gray, 1852 (Africa)
    • Cycloderma Peters, 1854 (Africa)
    • Lissemys Smith, 1931 (Asia)
  • the Trionychinae subfamily is characterized by braided pads insulating the cups:
    • Amyda Geoffroy Saint-Hilaire, 1809 (Asia)
    • Apalone Rafinesque, 1832 (North America)
    • Aspideretes Hay, 1904 (Asia)
    • Chitra Gray, 1844 (Asia)
    • Dogania Gray, 1844 (Asia)
    • Nilssonia Gray, 1872 (Asia)
    • Palea Meylan, 1987 (Asia)
    • Pelochelys Gray, 1864 (Asia)
    • Pelodiscus Fitzinger, 1835 (Asia)
    • Rafetus Gray, 1864 (Asia)
    • Trionyx Geoffroy Saint-Hilaire, 1809 (Africa)

Paleontology

The kind Palaeotrionyx disappeared. These tortoises measured 45 cm. One found of them many fossils with the higher Crétacé and the tertiary of France.

See too

Random links:Danny Blind | Eurofins Scientific | Competence (French right) | South of Santa Catarina | Rene Maingourd | Raven_Blanc-étranglé