Geometric tortoise (Psammobates geometricus)

loading
Geometric tortoise
loading
Loading more images and videos...

Geometric tortoise fact file

Geometric tortoise description

KingdomAnimalia
PhylumChordata
ClassReptilia
OrderTestudines
FamilyTestudinidae
GenusPsammobates (1)

The geometric tortoise, a medium-sized terrestrial tortoise, is the rarest of the three Psammobates (tent tortoise) species restricted to southern Africa (4) (5). It is named for the pattern adorning its high, domed shell, which occasionally may be perfectly geometric (6). The shell is dark brown or black and each scute has yellow stripes radiating out from a yellow centre (7). The rear edges of the shell are slightly upturned. Female geometric tortoises can be distinguished by their larger size and smaller tail (6), while the males typically have a concave plastron, or lower shell (2).

Synonyms
Testudo geometrica, Testudo luteola, Testudo strauchi.
French
Sakafi, Tortue Géométrique.
Spanish
Sacafi, Tortuga Geométrica.
Size
Male length: up to 12 cm (2)
Female length: up to 15 cm (2)
Top

Geometric tortoise biology

The geometric tortoise lays one to two clutches of two to five eggs in spring and early summer, which are incubated for a period of five to eight months before they hatch (5) (9). Typically, eggs hatch at the onset of the winter rains in the Western Cape (late April to May). This long-lived tortoise reaches sexual maturity at seven to eight years and may live for over 30 years (4) (5) (10). The geometric tortoise feeds on a wide range of grasses, reeds, sedges, herbs and shrubs (9).

Top

Geometric tortoise range

This species is restricted to the extreme south-western part of the Western Cape Province, South Africa (8), from near Cape Town, 160 kilometres north to Eendekuil, and east to the Upper Breede River Valley and the Ceres Valley (4) (5) (8).

Top

Geometric tortoise habitat

The geometric tortoise primarily inhabits a relatively narrow strip of coastal lowland, between the Cape Fold Mountains and the sea, with two isolated populations east of the mountains (4) (5) (8). The vegetation of this region forms part of the Cape Floral Kingdom or fynbos biome, and the geometric tortoise is restricted to a specific vegetation type within the fynbos biome, called renosterveld (8).

Top

Geometric tortoise status

Classified as Endangered (EN) on the IUCN Red List 2007 (1), and listed on Appendix I of CITES (3).

IUCN Red List species status – Endangered

Top

Geometric tortoise threats

The destruction of more than 90 percent of the renosterveld habitat in which the geometric tortoise resides has resulted in the depletion of tortoise numbers, and the range of this species continues to be reduced (2) (8) (11). This habitat loss has been the result of indiscriminate urban and agricultural development and unfortunately the geometric tortoise has proved to be intolerant of habitat modification (4) (12). The fynbos biome and renosterveld vegetation is adapted to fire, but too frequent unplanned and uncontrolled fires can result in local extinction of the geometric tortoise (4) (8). In addition, the spread of invasive alien vegetation in the region competes with, and excludes, important food items (8). The geometric tortoise is occasionally eaten by farm workers, and in the past it has been much sought after for the pet trade. However the impact of these activities is negligible compared to the major threat of habitat degradation and destruction (4).

Top

Geometric tortoise conservation

The geometric tortoise is protected by Western Cape Provincial legislation, which is rigidly and effectively enforced (4), and it is listed on Appendix I of the Convention on International Trade in Endangered Species (CITES), meaning that trade in this species is only permitted in exceptional circumstances (3). In addition, around 75 percent of the total population exists in formal protected areas (4), such as the Elandsberg Private Nature Reserve and a number of smaller provincial reserves (8). However, the majority of remaining geometric tortoise habitat is in the hands of private landowners and efforts are being made to secure the future of some of these sites through a conservation stewardship programme (13). Captive breeding of the geometric tortoise has had limited success and is currently not considered a priority, thus the primary focus of conservation efforts is to ensure its continued survival in the wild (4). The continued enforcement of conservation legislation and vigilance towards the unscrupulous collection of animals for the pet trade is called for (2), while the maintenance of protected areas is essential. In addition, it is imperative that private landowners take custodianship of the last remaining renosterveld remnants that contain geometric tortoise populations, in partnership with conservation agencies, since it is practically not possible to buy enough land to protect formally (2). Without such measures, the renosterveld habitat and its endangered inhabitants may disappear completely.

View information on this species at the UNEP World Conservation Monitoring Centre.
Top

Find out more

For further information on conservation of renosterveld habitat see:

Top

Authentication

Authenticated (17/04/08) by Dr Ernst Baard, Senior Manager: Scientific Services, CapeNature.
http://www.capenature.co.za

Top

Glossary

Cape Floral Kingdom
An area occupying about 90,000 square kilometres of South Africa that contains an incredibly high diversity of plant species (around 8,700 species), of which 68 percent are found no where else.
Fynbos
The natural shrubland vegetation occurring in the south-western and southern Cape of South Africa, holding the greatest diversity of plant species in the world. Fynbos is characterised by tall shrubs with large leaves, heath-like shrubs, wiry reed-like plants, and bulbous herbs.
Fynbos biome
Refers to the two key vegetation groups (fynbos and renosterveld) found within the Cape Floral Kingdom.
Renosterveld
One of the dominant vegetation types in the Cape Floral Kingdom. It grows on fertile soils where rainfall is moderate, and is characterised by a great richness in bulb plant species and other geophytes.
Scute
A large, bony plate or scale on the upper or lower shell of a turtle or tortoise.
Top

References

  1. IUCN Red List (September, 2007)
    http://www.iucnredlist.org
  2. Baard, E.H.W. (2008) Pers. comm.
  3. CITES (April, 2007)
    http://www.cites.org
  4. Groombridge, B. and Wright, L. (1982) The IUCN Amphibia-Reptilia Red Data Book. IUCN, Gland, Switzerland and Cambridge, UK.
  5. Boycott, R.C. and Bourquin, O. (2000) The Southern African Tortoise Book: A Guide to Southern African Tortoises, Terrapins and Turtles. O. Bourquin, Hilton, KwaZulu-Natal, South Africa.
  6. Branch, B. (1993) Southern African Snakes and other Reptiles. New Holland Ltd, London.
  7. Ernst, C.H., Altenburg, R.G.M. and Barbour, R.W. (1997) Turtles of the World. ETI Information Systems Ltd, Netherlands.
  8. Baard, E.H.W. (1993) Distribution and status of the geometric tortoise Psammobates geometricus in South Africa. Biological Conservation, 63: 235 - 239.
  9. Baard, E. (1994) Cape Tortoises; their identification and care. Cape Nature Conservation, Cape Town.
  10. Baard, E.H.W. (1995) Growth, age at sexual maturity and sexual dimorphism in the geometric tortoise, Psammobates geometricus. Journal of the Herpetological Association of Africa, 44(1): 10 - 15.
  11. Rouget, M., Richardson, D.M., Cowling, R.M., Lloyd, J.W. and Lombard, A.T. (2003) Current patterns of habitat transformation and future threats to biodiversity in terrestrial ecosystems of the Cape Floristic Region, South Africa. Biological Conservation, 112: 63 - 85.
  12. Baard, E.H.W. and de Villiers, A.L. (2000) State of Biodiversity: Western Cape Province, South Africa. Amphibians and Reptiles. Western Cape Nature Conservation Board, South Africa.
  13. Turner, A.A., De Villiers, A.L. and Baard, E.H.W. (2007) Western Cape State of Biodiversity 2007. Reptiles. Western cape Nature Conservation Board, South Africa.
X
Close

Image credit

Geometric tortoise  
Geometric tortoise

© Martin Harvey / www.photoshot.com

NHPA/Photoshot Holdings Ltd
29-31 Saffron Hill
London
EC1N 8SW
United Kingdom
Tel: +44 (0) 20 7421 6003
Fax: +44 (0) 20 7421 6006
sales@photoshot.com
http://www.photoshot.com

X
Close

Link to this photo

ARKive species - Geometric tortoise (Psammobates geometricus) Embed this ARKive thumbnail link ("portlet") by copying and pasting the code below.

Terms of Use - The displayed portlet may be used as a link from your website to ARKive's online content for private, scientific, conservation or educational purposes only. It may NOT be used within Apps.

Read more about

X
Close

MyARKive

MyARKive offers the scrapbook feature to signed-up members, allowing you to organize your favourite ARKive images and videos and share them with friends.

Play the Team WILD game:

Team WILD, an elite squadron of science superheroes, needs your help! Your mission: protect and conserve the planet’s species and habitats from destruction.

Conservation in Action

Which species are on the road to recovery? Find out now »

Help us share the wonders of the natural world. Donate today!

Blog RSS