Euphrates softshell turtle
The round to oval carapace (to 68 cm) is olive green, flecked with yellow, cream, or white in juveniles but without markings or with a few dark blotches in adults. Numerous longitudinal rows of small tubercles occur on the juvenile carapace, and some may persist into adulthood. A series of enlarged blunt tubercles lies above the neck on the anterior rim of the carapace. A single neural bone separates the 1st pair of costals due to the absence of a preneural. The 8th pair of costals is reduced in size and does not meet at the midline. Carapacial bones are coarsely pitted. The plastron is gray or white to cream colored and has only two poorly developed callosities (on the hyo- and hypoplastra). Its epiplastra do not touch and the entoplastron forms acute angles to the plastral midline. The skull is moderate in size with a short, bony snout. The triturating surface on the maxilla is ridgeless but rugose; the mandibular symphysis is narrower than the diameter of the orbit and always exhibits a more or less developed median ridge (Taskavak, 1999). The basisphenoid is medially constricted and not in contact with the palatines. The head, dorsal surface of the neck, and exposed parts of the limbs are green. The chin and undersides of the neck and limbs are whitish.
Sexual dimorphism is absent (Taskavak et al., in press).
Rafetus euphraticus is known from the Tigris and Euphrates drainages in southern Turkey, Syria, Iraq, and Iran. Reports that this species occurs in northeastern Israel are probably false and based on misidentified Trionyx triunguis (Balázs L. Farkas, pers. comm.).
Relatively shallow and calm rivers and ponds, and temporary pools in wetlands are preferred over deep, fast-flowing main river channels; the substrate generally is blackish mud (Taskavak et al., in press).
Gramentz (1991) reported nesting occurs in the end of May and beginning of June, but Taskavak et al. (in press) extend this to late-April to mid-September. Females may lay several clutches per season (Taskavak et al., in press). A 50 cm female contained 30 eggs (Gramentz, 1991); 19 hard, brittle-shelled eggs dissected from two females were spherical (to ellipsoidal), with a diameter of 23.34 ± 0.13 mm (Taskavak and Atatür, 1998).
Rafetus euphraticus is omnivorous: Taskavak (1992) and Taskavak and Atatür (1998) report it consumes considerable amounts of plant food (Chaetomorpha linum, tomatoes, watermelon), while animal prey taken includes insect larvae, crustaceans, mollusks, amphibians, and fish. Stomachs of dissected animals also contained bird remains (Gramentz, 1991; Taskavak and Atatür, 1998). Taskavak and Atatür (1998) observed several Rafetus euphraticus scavenging on a drifting horse carcass in the river Euphrates. Captives take invertebrates, raw frog meat, chopped beef, heart and liver, live white mice, and vegetable matter such as watermelon, cucumber, tomato, orange and banana (Taskavak and Atatür, 1998).
Rafetus euphraticus is diurnal and fond of basking close to the water, but dashes into the water at the slightest disturbance. Adults are active at water temperatures above 20°C (Gramentz, 1991), and the species is not tolerant of decreasing water temperatures; a local population in the upper Euphrates River in southeastern Turkey was seriously threatened (rather than extirpated; Ertan Taskavak, pers. comm.) when the water temperature dropped to 12.4°C due to construction of a dam about 60 km upstream (Gramentz, 1993b).
IUCN Red List Status (1996)
Endangered (A1ac+2c). Taskavak and Reimann (1998) discuss the theats this species is facing in Turkey and present a small-scale conservation measure.