Impressed tortoise (Manouria impressa)

Synonyms: Geochelone impressa, Geoemyda impressa, Testudo impressa, Testudo pseudemys
  
French: Tortue Imprimée
Spanish: Tortuga Marrón De Burma
KingdomAnimalia
PhylumChordata
ClassReptilia
OrderTestudines
FamilyTestudinidae
GenusManouria (1)
SizeLength: up to 31 cm (2)

The impressed tortoise is classified as Vulnerable (VU) on the IUCN Red List (1) and listed on Appendix II of CITES (3).

Despite first being described back in 1882 (4), the impressed tortoise remains something of an enigma, with very little known about the species either in the wild or in captivity (5). This tortoise can be identified by its relatively flattened carapace, which has a strongly serrated rim (2) and concave scutes, from which the common and scientific names derive (4). The carapace is a pale horn to dull orange colour, with brown colouring at the centre of each scute, blending into darker radiating streaks towards the edges, which contrast starkly with the pale under-colour. These markings fade with age, however, and older adults may be nearly uniformly horn coloured (4). While the limbs and tail are dark brown to black, the head is a conspicuous yellow to tan colour, with pink pigment around the snout of some individuals (2).

The impressed tortoise occurs in Myanmar, Thailand, Vietnam, Laos (Lao People's Democratic Republic), Cambodia and Malaysia, and has also been reported in China, although the validity of these reports has been questioned and its status here requires confirmation (3).

The preferred habitat of the impressed tortoise is unknown, but there is some consensus that it is an upland species of hills and mountains (4). This species is thought to inhabit evergreen forests and bamboo thickets, and is not believed to be associated with bodies of water, relying instead on heavy dew or rain-drenched vegetation for water. Much time may be spent hiding under leaf litter of the forest floor (2).

The mating season of the impressed tortoise reportedly coincides with the rainy season, with courtship activity observed from mid-March to September. The male courtship ritual involves bobbing the head up and down of in front of a female, whilst simultaneously opening and closing the mouth. The eggs are laid in a shallow cavity and then covered with leaves to conceal them from predators. One report exists of a clutch of 17 eggs being laid in May (2). In captivity, the female guards the eggs for between three and twenty days after laying them, continuously adding more material to the nest (5).

The available evidence suggests that the impressed tortoise is most active at twilight and during showers (2). Although previous reports exist of this species feeding on grasses, bamboo sprouts, and fruits (4), a more recent study in 1996 claimed that the diet is almost entirely composed of mushrooms (2).

The impressed tortoise is declining in the wild due to exploitation for the Chinese and Vietnamese food markets, and habitat loss as the result of agricultural expansion and uncontrolled forest fires (2). Additionally, the tortoise’s collection for the pet trade seems to have grown in recent decades, with 1,634 specimens legally exported between 1986 and 1990, mostly from Malaysia and Thailand, with the total number for 1990 being over double the total for 1988 (4). This is particularly tragic considering the notorious difficulty of maintaining this delicate and highly sensitive species in captivity (4), with almost 100% mortality during the adaptation process to captivity (6).

Thailand banned the legal export of impressed tortoises in 1992 (4) and the species is conferred a degree of protection through its listing on Appendix II of CITES, which limits and regulates the quota that can be legally exported (3). Nevertheless, poaching for the Asian food and western pet market continue, alongside ongoing habitat destruction, providing little optimism for the long-term survival of this poorly known species, which may sadly vanish before its biology and ecology are truly understood (4).

For more information on the impressed tortoise see:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

  1. IUCN Red List (June, 2006)
    http://www.iucnredlist.org
  2. Turtles of the World (CD-ROM), by Ernst, C.H., Altenburg, R.G.M. and Barbour, R.W. (June, 2006)
    http://nlbif.eti.uva.nl/bis/turtles.php?selected=beschrijving&menuentry=soorten&id=368
  3. CITES (May, 2006)
    http://www.cites.org
  4. Espenshade, W.H. and Buskirk, J. (1994) Manouria impressa (Günther 1882): A Summary of Known and Anecdotal Information. Tortuga Gazette, 30(5): 1 - 5. Available at:
    http://www.tortoise.org/archives/impressa.html
  5. Central Pets (June, 2006)
    http://www.centralpets.com/animals/reptiles/tortoises/tor4984.html
  6. World Chelonian Trust (June, 2006)
    http://www.chelonia.org/sexing/sexing_Manouria_impressa.htm