Biology
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The flat-shelled spider tortoise is active only during the hot/rainy season (4) (5), from December until around March (6), and is most active during and after rains (4) (5). During the cooler dry season, this species buries itself and lies dormant in the leaf litter of the forest floor (a period known as aestivation) (4). Breeding occurs during the hot/rainy season, and is followed a month later by egg-laying (5). Females may produce up to three clutches a year (5), each containing only one, relatively large egg (4). Hatching is timed with the return of the rainy season the following December (5).
The diet of the flat-shelled spider tortoise consists of fallen fruits from trees, and the shoots and leaves of bushes (4).
Conservation
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The majority of the flat-shelled tortoise's range now occurs within the recently designated Menabe Antimena protected area, which offers some hope that a significant proportion of its remaining habitat will be preserved (6). Other protected areas of forest occur within this species' range, such as the special Andranomena Forest Reserve and private Analabe Reserve, but regulations are believed to have been rarely enforced and the precise status of the species in these areas is currently unknown (2).
The flat-shelled spider tortoise has proven difficult to breed in captivity (2). Thus, creating an effective and sustainable captive-breeding programme to supply demand or to fuel reintroduction efforts would appear difficult. The flat-shelled spider tortoise was raised from Appendix II to Appendix I of CITES in 2003, banning all international trade in wild-caught specimens (3), which is thought to have been largely successful, although some illegal collection from the forest is still suspected to continue (2) (6).
Description
provided by Arkive
The various English common names for this small tortoise generally refer to the noticeably flattened nature of either its oblong upper shell (carapace) or its tail (2) (4). The carapace is distinctively patterned, with each scute having a light brown to yellow centre surrounded by a wide, dark brown to black border. In older tortoises, an additional yellow border may surround this dark border (4). Yellow rays extend outward from the centre of the scutes, across the dark border. The scutes around the perimeter of the shell (marginals) are dark with a yellow band (2) (4). The lower shell (plastron) is yellow with scattered dark spots or rays along the sides (2) (4). The limbs range from yellow to brown in colour, and large yellow scales cover the hind legs (2). By contrast, the head ranges from dark brown to black, with some variable yellow markings (2) (4).
Habitat
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Confined to lowland fragments of dry, deciduous forest, found only on the west coast of Madagascar (5).
Range
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Endemic to the west coast of Madagascar (5), between the Monrondava and Tsiribihina Rivers (4).
Status
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Classified as Endangered (EN) on the IUCN Red List (1), and listed on Appendix I of CITES (3).
Threats
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Like Madagascar's other tortoises, the flat-shelled spider tortoise has been severely threatened by rampant degradation of its habitat and harvesting for the international pet trade (2). Deforestation has been widespread largely due to conversion to agriculture and timber extraction (2) (5) (6). The species' already precarious position has been compounded by excessive harvesting to sell to private collectors, which has resulted in its total elimination from some forest fragments. This species has also been sold in Chinese marketplaces for food. Even since their listing on Appendix I of the Convention on International Trade in Endangered Species (CITES), with export of wild specimens therefore banned, there have still been reports of tortoises being smuggled out illegally. In addition, there are serious concerns that specimens advertised as 'captive-bred' are really captured from the wild. Given that the species has a low reproductive rate, and it is mostly breeding females that are collected, the flat-shelled spider tortoise has little capacity to recover from sustained over-harvesting. Floods caused by cyclones are one of the natural threats which this species has to endure (2).
Distribution
provided by ReptileDB
Continent: Indian-Ocean
Distribution: SW Madagascar (vicinity of Morondava)
Type locality: "Mouroundava, ouest de Madagascar," restricted by Bour 1981:165, to "Morondava, province de Tulear, Madagascar (puirrait etre restrainte a la foret d'Andranomena).
Flat-backed spider tortoise
provided by wikipedia EN
The flat-backed spider tortoise (Pyxis planicauda), more commonly known as the flat-tailed tortoise, and Madagascan flat-tailed tortoise, is a tortoise that belongs to the family Testudinidae.[4] The various common names for this small tortoise usually refer to the noticeably flattened nature of its oblong upper-shell or its tail.[4]
The flat-backed spider tortoise is endemic to the west coast of Madagascar, between the Monrondava and Tsiribihina rivers. Due to the specifications of its habitat, the flat-backed spider tortoise is classified as critically endangered on the IUCN Red List.[4]
Description
The flat-backed spider tortoise receives its name from its distinctive physical appearance. Its upper-shell (carapace) and tail are outstandingly flatter than the common tortoise.[4] Its carapace is patterned, with each scute ranging in color from light brown to yellow center and a dark brown to black outline. In older tortoise, an additional yellow border can be seen that surrounds the dark outline. Yellow rays extend outwards from the center of each scute.[4] Scutes along the borders of the shell (marginal) are usually dark in color, surrounded by a yellow band. The lower shell (plastron) usually appears to be yellow in color, with scattered dark spots or rays. The limbs are covered with scales that range from yellow to brown in color. The head, on the other hand, is usually darker in color (ranges from dark brown to black, with some yellow markings).[4][5]
Habitat and behavior
The flat-backed spider tortoise is confined to lowland fragments of dry, deciduous forest, found only on the west coast of Madagascar.[1] It is concentrated between the Monrondava and Tsirbihina rivers. The forests inhabited by the flat-backed spider tortoise grow on loose sandy soils and the tortoises take shelter amongst the leaf litter of the forest floor during their inactive seasons.[1] The flat-backed spider tortoise is active only during the warm/raining season (December–March), with most activity concentrated during and after rain.[6] During the cooler dry season the flat-backed spider tortoise enters a stage similar to hibernation known as aestivation, the species buries itself and lies dormant.[1]
Mating season usually takes place during the hot/rainy season, and is followed a month later by egg-laying. Females may produce up to three clutches a year, each containing only one relatively large egg. Hatching is therefore timed with the return of the rainy season, when the species is most active.[1]
Threats
Due to its habitat restrictions, the flat-backed spider tortoise is considered to be critically endangered[4] . Its major threat comes from habitat loss due to the process of deforestation, particularly from burning and clearing for agricultural lands/cattle grazing, highway development, mining, and petroleum exploration.[7] A combined forest habitat loss of 70% has been estimated for the period (1963-2040).[1]
Another threat arises from the collection for pet trade. Pet trade is estimated to have removed about 4,000 adults during 2000 to 2002, representing 20 to 40% of the total number of adults (depending on the estimated population of adults[7]).[1] The reproductive nature of this species does not make it eligible of excessive pet trading since they are particularly low even by tortoise standards, with females producing up to three clutches a year consisting only of one egg each.[4]
References
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^ a b c d e f g Leuteritz, T.; Randriamahazo, H.; Lewis, R.; et al. (Madagascar Tortoise and Freshwater Turtle Red List Workshop) (2008). "Pyxis planicauda". IUCN Red List of Threatened Species. 2008: e.T19036A8789990. doi:10.2305/IUCN.UK.2008.RLTS.T19036A8789990.en. Retrieved 12 November 2021.
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^ "Appendices | CITES". cites.org. Retrieved 2022-01-14.
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^ Fritz Uwe; Peter Havaš (2007). "Checklist of Chelonians of the World" (PDF). Vertebrate Zoology. 57 (2): 293–294. ISSN 1864-5755. Archived from the original (PDF) on 2011-05-01. Retrieved 29 May 2012.
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^ a b c d e f g h "Flat-shelled spider Tortoise (Pyxis planicauda)". Archived from the original on 2014-03-06. Retrieved 10 August 2013.
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^ "Anatomy of the turtle's shell". Retrieved 11 August 2013.
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^ Zovickian, William. "Spider Tortoises". Retrieved 10 August 2013.
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^ a b Young, Richard P.; Volahy, Anselme Toto; Bourou, Robert; Lewis, Richard; Durbin, Joanna; Fa, John E. (2008). "Estimating the population of the Endangered flat-tailed tortoise Pyxis planicauda in the deciduous, dry forest of western Madagascar: a monitoring baseline". Oryx. 42 (2). doi:10.1017/S0030605308006844. ISSN 0030-6053.
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Flat-backed spider tortoise: Brief Summary
provided by wikipedia EN
The flat-backed spider tortoise (Pyxis planicauda), more commonly known as the flat-tailed tortoise, and Madagascan flat-tailed tortoise, is a tortoise that belongs to the family Testudinidae. The various common names for this small tortoise usually refer to the noticeably flattened nature of its oblong upper-shell or its tail.
The flat-backed spider tortoise is endemic to the west coast of Madagascar, between the Monrondava and Tsiribihina rivers. Due to the specifications of its habitat, the flat-backed spider tortoise is classified as critically endangered on the IUCN Red List.
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