Asian Giant Tortoise

The Asian forest tortoise (''Manouria emys''), also known commonly as the Mountain tortoise or Burmese Brown Mountain tortoise, is a species of tortoise in the family Testudinidae. The species is endemic to Southeast Asia. It is believed to be among the most primitive of living tortoises, based on molecular and morphological studies.

Taxonomy

There are two recognized subspecies: ''M. e. emys'' occurring in southern Thailand, Malaysia, Sumatra, Borneo; and ''M. e. phayrei'', occurring from northwestern Thailand to northeastern India. The latter was named after Sir Arthur Purves Phayre (1812–1885), British Army officer in India who became Commissioner of British Burma.

Based on a variety of phylogenetic characteristics, the genus '' Manouria'' is regarded as comparatively primitive and basal to other Testudinidae.

Description

The Asian forest tortoise is the largest tortoise in mainland Asia. The largest adults of the northern subspecies, ''Manouria emys phayrei'', can reach 25 kg (55 lb) in the wild and much more in captivity.It has a broad, flattened upper shell and a large lower shell, with distinctive features on its head, limbs, and skin that set it apart from other tortoises.

The carapace is considerably depressed (flattened), its depth less than half its length. Anterior and posterior margins are reverted (upturned) and strongly serrated (toothed). A nuchal (neck) shield is present, along with two supracaudal (above the tail) shields. Dorsal shields show concentric striations (grooves) and are often concave. Vertebral shields are much broader than long and at least as broad as costals (side plates). The lower shell (plastron) is large, with the gular region (throat area) produced (slightly extended) and typically notched (indented). The hind lobe (rear section) is deeply notched (indented). Pectoral shields may be widely separated or joined by a short median suture (seam). The axillary (armpit) shield is very small, while the inguinal (groin) shield is large. The head is moderate in size, featuring two large prefrontal shields and a large frontal shield. The beak is not hooked. Jaws are feebly denticulated (weakly toothed), with a strong median ridge (raised line) on the upper jaw’s alveolar surface (inner surface). Anterior forelimb surfaces have large, bony, pointed, imbricate tubercles (overlapping bumps) in four or five longitudinal series. Hind limbs bear large bony tubercles (bumps) on the plantar surface (sole), with larger, conical, spur-like tubercles (bumps) on the heel and a group of even larger conical tubercles (bumps) on each side of the thighs’ posterior. Adults are dark brown or blackish. Juveniles have a yellowish-brown carapace with dark-brown markings.

Distribution

The Asian forest tortoise occurs in Bangladesh, Cambodia, India, Indonesia, Malaysia, Myanmar, Thailand, and Vietnam.

Diet

''Manouria emys'' has been observed in the wild to consume whole fungi, shoots of koster's curse ('' Miconia crenata''), leaves and petioles of elephant ears ('' Alocasia sarawakensis and Alocasia scabriuscula),'' shoots of ''Begonia sp.'', shoots of ''Phrynium sp.,'' shoots of vegetable fern ('' Diplazium esculentum),'' and flowers of wild ginger ('' Etlingera coccinea).'' Most commonly eaten were plants of the genus ''Alocasia,'' with individuals observed standing nearly vertical to reach leaves. In captivity, individuals have accepted a wide variety of food, predominantly being herbivorous but occasionally consuming frogs, snails, or carrion when presented.Høybye-Mortensen K. 2004.  ''M. Sc. Thesis'', University of South Denmark. p. 100

Reproduction

''Manouria emys'' is the only tortoise which lays its eggs above ground in a nest, which the female constructs of leaf litter. The female uses both front and rear legs to gather material for the nest and lays up to 50 eggs deep inside it. She then sits on and near the nest to protect it, and will "chase" predators and intruders away.

Preliminary research has been conducted into Temperature-Dependent Sex Determination (TSD) in Manouria Emys Emys, and an estimated pivotal temperature of 29.29°C was determined. Incubation temperatures higher than this produce high rates of female hatchlings, and lower than this produce high rates of males.

A correlation was also seen between temperature and incubation time, with higher temperatures resulting in a shorter incubation time, and lower temperatures resulting in a longer incubation time. Incubation time ranged from 60 to 90 days.

Cited references

Further reading

*
* Blyth E (1854). "Notices and Descriptions of Various Reptiles, New or Little-known. Part I". ''J. Asiatic Soc. Bengal'' 22 853 639–655.
* Schlegel H, Müller S (1844). "''Over de Schildpadden van den Indischen Archipel'' ". In: Temminck CJ (1839–1847). ''Verhandelingen over de natuurlijke geschiedenis der Nederlandsche overzeesche bezittingen, door de leden der Natuurkundige Commisie in Oost-Indie en andere schrijvers. Leijden folio. Afd. 1 Zoologie in 12 afleveringen, met 45 gekl. pl. - Vitg. door C.J. Temminck, Leiden, Leuchtmans u. Hoeck in comm.'': 29–36. (''Testudo emys'', new species, p. 34 + Plate IV). (in Dutch).
*

External links

*
* http://www.tortoise.org/archives/manouria.html

{{Taxonbar, from=Q900757

Manouria
Reptiles of India
Reptiles of Borneo
Reptiles of Bangladesh
Reptiles of Myanmar
Reptiles of Vietnam
Reptiles of Cambodia
Reptiles of Thailand
Reptiles of Indonesia
Reptiles of Malaysia
Reptiles described in 1844