Ringed map turtle (Graptemys oculifera)
|Also known as:||Ringed sawback|
|Size||Male carapace length: up to11 cm (2)|
Female carapace length: up to 22 cm (2)
The ringed map turtle is classified as Vulnerable (VU) on the IUCN Red List (1) and listed on Appendix II of CITES (3).
The characteristically narrow-headed ringed map turtle (Graptemys oculifera) is one of the most poorly known turtles in the United States (2). The upper shell, or carapace, has flattened, black, spine-like projections running along the centre, and a slightly serrated edge (2). The carapace is a mainly dark olive-green, with yellow or orange eye-like spots on the bony-plates, or scutes, running along its back. A wide yellow semicircle patterns the outermost scutes (2). The underside of the shell, or plastron, is yellow or orange (2).
The skin covering the head and body is black with vibrant yellow stripes. The adult male differs from the female in having a long, thick tail, elongated foreclaws and a narrower head (2).
The ringed map turtle is endemic to the United States, where it is restricted to the Pearl River and its major tributaries in the states of Mississippi and Louisiana. It is not found in the lower-most section of the West Pearl River, which is tidally influenced (1) (2).
The total length of river occupied by the ringed map turtle is just 875 kilometres (1).
The ringed map turtle prefers wide, sand- or clay-bottomed rivers with strong currents and adjacent white sand beaches (2). An abundance of basking sites in the form of brush, logs and debris is also an important part of its habitat (2).
Like many species of reptile, the ringed map turtle is cold-blooded and spends much of its day basking in the sun (2). At night, it rests on branches and other partially submerged wood (2). Its diet consists mainly of a range of insects including caddisfly larvae, aquatic beetles and their larvae, mayflies and dragonfly nymphs. It is also known to feed on plant matter and the material scraped from submerged logs (1) (2).
The male ringed map turtle becomes sexually mature when the plastron reaches 65 centimetres in length. Mating has been observed to occur in April (2), and the female is gravid for approximately two and a half weeks before laying a clutch of around three or four eggs (4). The eggs are deposited in nests on sandbars, approximately 18 metres from the water’s edge. The female can lay two clutches per year (4). The eggs are laid from mid-May to mid-July, peaking in mid-June, and the hatchlings begin to emerge after sunset in late July and early August (2) (4).
The eggs and juveniles of the ringed map turtle are preyed upon by numerous species, including ants, snakes, crows, racoons, canids and also humans (2). Boat traffic in some areas can cause mutilation and even death of adults, and they also often become hooked on fishing lines and are subsequently killed by fishermen (2).
Habitat modification and water-quality degradation have also had a detrimental impact on this species (1). In addition, it is suspected that illegal collecting, assumed to be for the pet trade, may have added to the decline of this species (3).
In Louisiana, the ringed map turtle is listed as a ‘Species of Special Concern’ meaning that any person involved in the acquiring, handling, buying or selling of this reptile must hold either a collectors license or a reptile wholesale or retail dealers license (3). It is also protected by law in Mississippi (1).
A 19 kilometre stretch of the Pearl River has been designated as a turtle sanctuary, with a further 240 kilometres of river habitat suggested for future protection. Further studies on aspects of this species’ ecology would also be beneficial in understanding how best to conserve it (1).
Find out more about the ringed map turtle and its conservation:
US Fish & Wildlife Service species profile - Ringed map turtle:
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- Carapace: the top shell of a turtle or tortoise. In arthropods (insects, crabs etc), the fused head and thorax (the part of the body located near the head), also known as the ‘cephalothorax’.
- Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
- Gravid: carrying developing young or eggs.
- Larva: stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
- Plastron: the lower shell of a turtle or tortoise.
- Scute: a large scale on the shell of a turtle or tortoise.
IUCN Red List (September, 2011)
- Ernst, C.H. and Lovich, J.E. (2009) Turtles of the United States and Canada: Second Edition. The John Hopkins University Press, Baltimore.
CITES (September, 2011)
- Jones, R.L. (2006) Reproduction and nesting of the endangered ringed map turtle, Graptemys oculifera, in Mississippi. Chelonian Conservation and Biology, 52(2): 195-209.