Tortoises

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Tortoises
Leopard tortoise (Stigmochelys pardalis)

Panther turtle ( Stigmochelys pardalis )

Systematics
without rank: Amniotes (Amniota)
without rank: Sauropsida
Order : Turtles (Testudinata)
Subordination : Halsberger tortoises (Cryptodira)
Superfamily : Terrapins and tortoises (Testudinoidea)
Family : Tortoises
Scientific name
Testudinidae
Batsch , 1788
Bony anatomy of a tortoise ( sagittal plane )

True tortoises (Testudinidae) are the most adapted to a terrestrial lifestyle family of turtles . The ancient turtle Chinlechelys tenertesta already lived terrestrially, as finds from the late Triassic show. From the Eocene , they are widespread in tertiary deposits. The genus Chinlechelys is not closely related to the recent tortoises, which are predominantly found in the tropics and subtropics of the Old World . There are only a few tortoises in North , Central and South America and none at all in Australia . The Moorish tortoise Testudo graeca , the Greek tortoise Testudo hermanni and the wide-brimmed tortoise Testudo marginata live in southern Europe .

The size of the recent tortoises ranges from a few centimeters to just under a meter. The largest known tortoise of all time was the extinct Colossochelys atlas with a shell length of up to 2.5 meters.

Up to now 16 recent genera and 59 species of tortoises have been distinguished, plus the genus Cylindraspis , whose 5 species became extinct in historical times.

Appearance

Tortoises usually have a domed shell. Exceptions to this are the East African column turtles and the South African flat turtles, which seek refuge in narrow crevices while fleeing from predators. The legs of the tortoises are wide, the hind legs are columnar. Some ground-digging turtles, such as the gopher tortoises , have their front legs flattened and covered with scales. In all species, fingers and toes do not have more than two phalanges and are fused up to the claws. Most species exhibit pronounced sexual dimorphism , with males having thicker tails and a concave belly armor that makes mating easier. In many female turtles, on the other hand, there is a V-shaped incision in the plastron below the tail, which favors egg-laying.

The sawn flat turtle with an average shell length of 7 - 9 centimeters and the Egyptian tortoise with 12 centimeters are considered the smallest species of tortoise . The largest are the Galápagos giant tortoise ( Chelonoidis nigra ) and the Seychelles giant tortoise ( Dipsochelys ) at 70–95 centimeters

Reproduction

Female tortoises carefully choose where to lay their eggs, but do not care for the brood after they have laid their eggs. The sun provides the necessary incubation temperature. The females dig nesting holes with their hind legs, in which they lay between one and thirty eggs, depending on the species and age. The egg size also depends on the species, or on the size and age of the individual mother animal. For some species, multiple clutches are possible per season, depending on the supply situation of the dams. Eggs are usually laid during the day. After the clutch has been deposited, the nest cavity is carefully closed again and the ground leveled to make it more difficult for nest robbers to find it. The time it takes for the young to hatch depends on the climatic conditions and can be between 60 and 150 days.

Young turtles are already physically fully developed by the time they hatch. After hatching, they dig themselves to the surface of the nesting pit and immediately begin an independent life. After hatching, they pull in remnants of the yolk sac and are still supplied with nutrients for some time after hatching. After that, like the adult animals, they eat mostly vegetarian food.

Systematics

Coal turtle ( Chelonoidis carbonaria )
Galápagos giant tortoise ( Chelonoidis nigra )
Spurred Tortoise ( Centrochelys sulcata ) previously ( Geochelone sulcata )
California gopher tortoise ( Gopherus agassizii )
Stutz jointed turtle ( Kinixys homeana )
Tortoise ( Malacochersus tornieri )
Brown forest turtle ( Manouria emys )
Spiked- Edge Tortoise ( Psammobates oculifer )
Malagasy spider turtle ( Pyxis arachnoides )
Greek tortoise ( Testudo hermanni )

Up to now 16 recent genera and 59 species of tortoises have been distinguished, in addition there is the genus Cylindraspis , whose 5 species became extinct in historical times and several fossil tortoises such. B. the Atlas turtle. In addition to several newly described species, the main differences to older classifications are that the spurred turtle was placed in the new genus Centrochelys and the Galápagos giant tortoise ( Chelonoidis nigra ) is now considered a species complex , which means that 9 of its subspecies have been granted species status.

supporting documents

Individual evidence

  1. ^ WG Joyce, SG Lucas, TM Scheyer, AB Heckert, AP Hunt: A thin-shelled reptile from the Late Triassic of North America and the origin of the turtle shell. In: Proceedings of the Royal Society B. 2008.
  2. Tortoise Trust Egg FAQ ( Memento of the original from September 5, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.tortoisetrust.org
  3. Tortoise egg incubation ( Memento of the original from September 5, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.tortoisetrust.org
  4. N. Poulakakis, DL Edwards, Y. Chiari, RC Garrick, MA Russello, E. Benavides et al: Description of a New Galapagos Giant Tortoise Species (Chelonoidis; Testudines: Testudinidae) from Cerro Fatal on Santa Cruz Island. In: PLoS ONE. 10 (10), 2015, p. E0138779, doi: 10.1371 / journal.pone.0138779 .
  5. ^ Uwe Fritz: Handbook of the reptiles and amphibians in Europe. Turtles (Testudines) I . Aula Verlag, Wiebelsheim 2001, ISBN 3-89104-004-0 .

literature

Web links

Commons : Tortoises (Testudinidae)  - Collection of images, videos and audio files