Spurred tortoise
| Spurred tortoise | ||||||||||||
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Spurred Tortoise ( Centrochelys sulcata ) |
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Centrochelys | ||||||||||||
| JE Gray , 1872 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Centrochelys sulcata | ||||||||||||
| ( Miller , 1779) |
The spurred turtle ( Centrochelys sulcata ) belongs within the family of tortoises (Testudinidae) to the recently monotypical genus Centrochelys , previously it was included in the genus Geochelone . Spurred tortoises are the third largest living tortoises after the Galápagos giant tortoises ( Chelonoidis nigra ) and the Seychelles giant tortoises ( Dipsochelys ) and reach a back shell length of about 80 cm and a weight of over 80 kg. They colonize a dry area of distribution with sparse vegetation in north central Africa , which stretches like a narrow band over 8000 km from the Atlantic to the Red Sea . So far, no subspecies have been described.
description
The flattened back armor Carapax has curved edge shields with a sawn rear edge. The growth rings are very pronounced and remain visible even with age. A distinctive feature of this species are upwardly curved, forked throat shields (gulare), which protrude over the edge of the back armor. The armor color ranges from brown, olive to yellow-orange to cream-colored. The belly shell also shows clearly recognizable growth rings . Very old animals are light, sometimes almost white. The individual shields are clearly dark at the edges. The skin is beige and turns yellow in places. It is named after the noticeable spur on the thighs of the hind legs , which is present in both sexes .
For wild spurred turtles a maximum back armor length of 83 cm is given, combined with a weight of up to 105 kg. Animals in captivity may become even bigger and heavier. However, reliable information is not available.
Gender differences
The spurred turtle shows a pronounced sexual dimorphism , only juveniles are difficult to differentiate according to sex. Male animals are larger than females, which usually only reach 60–70 cm and weigh around 45–60 kg. Males have a clearly inwardly curved plastron and a longer tail. The marginal shields are also more arched up, the thigh spurs larger and the throat shields more pronounced.
Systematics
The spurred tortoise was first given a scientific name, Testudo sulcata , by the English animal and plant draftsman John Frederick Miller in 1779 . For a long time later it was assigned to the genus Geochelone Fitzinger , 1835. According to a proposal by the French herpetologist Roger Bour in 1985, however, it is now placed in the former subgenus Centrochelys Gray , 1872, which has meanwhile been raised to the rank of genus . Subspecies have not yet been described.
- Holotype : meanwhile no longer traceable
- Terra typica : "India occidentali [s]" ( West India , which turned out to be an error)
- Origin of the name: kentron gr., Sting; chelys, gr., turtle; sulcatus, a, around Latin, furrowed.
Way of life in nature
Spurred turtles are cold-blooded reptiles that have to minimize seasonal and daily temperature fluctuations through appropriate behavior in order to be able to maintain a suitable body temperature. With this type of thermoregulation, seeking shelter at the appropriate time of year and time plays an important role. For this purpose, spurred turtles use burrows in the ground that can be up to 4 m deep and 15 m long. If available, the abandoned buildings of other animals are used. But from the age of 2–3 years spurred turtles dig underground tunnels themselves with their strong front legs and sometimes with their forked throat shields. Usually they don't just use a single cave, but “own” several, which are occasionally shared with other spurred turtles and even other animal species. In the cooler season of the year, the spurred turtle leaves its burrow in the morning and warms up before it goes looking for food. In the hotter season, however, it often only becomes active in the evening hours. In the intermediate periods it is often active in two phases, i.e. that is, she returns to her cave in the hot time of the day. In particular, the wetter season is used intensively, whereas the hot dry periods to protect against dehydration must also be survived inactive in the cave. During this summer dormancy , the metabolism and heartbeat are severely reduced , similar to the winter rigor of other species .
distribution and habitat
The range of the spurred turtle is the African Sahel zone , which borders on the Sahara in the south. CITES lists stocks in the following countries: Ethiopia, Egypt, Benin, Eritrea, Mali, Mauritania, Niger, Nigeria, Senegal, Somalia, Sudan, Chad and Togo. In some parts of this distribution area, however, it was naturalized by humans. In parts of the distribution area, the population must be classified as endangered.
The spurred turtle lives in three different vegetation zones. These include dry and hot grassland with a semi-desert character, leafy bush and grassland with acacia trees. Daytime temperatures of over 40 ° C are the rule in their area of distribution. Even 50 ° C can be reached. The minimum temperature values are 3–21 ° C. In some biotopes, however, night frosts can occasionally occur. The sparse vegetation in the spurred tortoises' habitat consists mainly of various acacia species, baobabs, tamarinds, thorn bush species, long filaments and various wild millet species, Digitaria sp., Panicum sp., Prickly grasses Cenchrus sp. and a sparse, mostly annual growth of herbs and grasses.
food
The spurred turtle is predominantly vegetarian . Depending on the season, these are fresh, green shoots of succulents , herbs and grasses, but in the vast majority of cases dry and dead plant parts, because rainfall is rare in their area and can sometimes be absent for months or years. The preferred food plants include button grass, Dactyloctenium aegypticum , and finger millet, thread millet or dwarf millet Digitaria sp., Eragrostis sp., Also senna (syn. Cassia) obtusifolia and succulent plants such as day flowers Commelina benghalensis and summer purslane Portulaca oleracea . In addition, insects are captured and carrion, bones and feces are eaten by mammals.
Because they rarely have enough drinking water available, the spurred turtle uses water very sparingly and only excretes extremely small amounts of urine, even less in volume than the much smaller European tortoises.
Reproduction
The onset of sexual maturity in tortoises is less tied to a certain age than to a certain height or weight. Spurred turtles become sexually mature at around 15–20 kg, the weight of females in nature at around 10–12 years, males only around 3 years later. When kept in captivity, adult size can be reached much earlier.
The mating season is not limited to any particular season, but cooler and wetter months are preferred. The males actively search for females and often have to cover very long distances (10–20 km, sometimes significantly more). If you have found a female, try to prevent her from escaping by ramming it against the shell or biting her head and extremities. This can lead to severe mating injuries, sometimes resulting in death. If the male has managed to get up, mating takes about 15 minutes, but is usually repeated several times a day. The male makes hoarse grunts that can be heard from afar. Occasionally there are territorial fights among the males, which are as violent as the mating, with powerful bites and rams from the armor and throat shield.
Eggs are laid about a month after mating, preferably in the more humid root area of bushes. The eggs are laid in up to 9 clutches per year, but mostly there are 2–3 eggs with up to 40 eggs per clutch. The eggs are placed in self-dug earth hollows, which are carefully closed again after the eggs have been laid. In the wild, the young prefer to hatch shortly before the onset of the rainy season and therefore after very different breeding seasons, around 120 days on average. But much longer incubation times are also described. When hatching, the young weigh an average of about 40 g and are about 5 cm long.
Danger
The spurred turtle is listed as endangered in the Red List and listed as an endangered species in Appendix II of the Washington Convention on Endangered Species . The reasons for this are collection for personal use (pets, food) and exports, dismemberment and urban sprawl of the once huge distribution area, advancement of the desert into the distribution area. On the other hand, breeding in human care is very successful.
gallery
Spurred tortoise
Rump
leg
head
copulation
Young spurred turtle
literature
- MRK Lambert: On growth, sexual dimorphism, and the general ecology of the African spurred tortoise, Geochelone sulcata, in Mali. Chelonian Conserv. Biol. 1 (1) pp. 37-46, 1993
- MRK Lambert: On general biology and utilization of the African spurred tortoise, Geochelone sulcata, in Mali, West Africa. - In: B. Devaux (ed.), Proceedings — International Congress of Chelonian Conservation, pp. 112-114. Gonfaron, France: Editions SOPTOM, 1996
- Holger Vetter: Panther and Spurred Tortoise - Stigmochelys pardalis and Centrochelys sulcata . Turtle Library Volume 1, Edition Chimaira, Frankfurt am Main 2005, ISBN 3-89973-501-3
Web links
- Centrochelys sulcata in the endangered Red List species the IUCN 2006. Posted by: Tortoise & Freshwater Turtle Specialist Group, 1996. Retrieved on 11 May, 2006.
- Centrochelys sulcata in The Reptile Database
Individual evidence
- ^ A b John Frederick Miller: Icones Animalium et Plantarum. London 1776–1782, plate 26 ( associated inscriptions )
- ↑ Roger Bour: Les tortues terrestres géantes the îles de l'océan India occidental: données géographiques, taxinomiques et phylogénétiques. Pp. 17–76 in: F. De Broin, E. Jiménez-Fuentes (ed.): Comunicaciones del I Simposium Internacional sobre Quelonios Fósiles, París, Octubre, 1983. Studia Geologica Salmanticensia, Volume Especial 1 (Studia Palaeocheloniologica 1), 1985 ( PDF 2.9 MB), p. 63 ff.
- ^ CITES Species Database
- ↑ Manfred Rogner: Tortoises - Biology, Keeping, Multiplication , Eugen Ulmer KG, Stuttgart 2008, ISBN 978-3-8001-5440-1 , p. 81