The Herpetological Journal

pp.115-120

Authors: John Davenport And Tat Meng Wong

Abstract: Black-rayed softshell turtles (Amyda cartilaginea) from Malaysia were shown to be capable of extracting oxygen from water by a combination of cutaneous and buccopharyngeal respiration. Given access to air as well as water they consumed a mean 81 ml 0₂ g^·1h^-1; when submerged and respiring aquatically the uptake fell to a mean value of 21 ml 0₂ g^·1h^·1 (ratio 3.86:1 ). Behavioural data show that the turtles cannot survive indefinitely by aquatic respiration alone as they incur an oxygen debt, even when inactive. Scope for activity is substantially reduced, even when air becomes available, until the oxygen debt is repaid. Buccopharyngeal respiration is a normal feature of behaviour, and is not used solely during prolonged submergence. The turtles pump some 40-80 ml water min-' through the pharynx at 30ºC. Turtles display dilated cutaneous blood vessels when they are submerged for long periods.