Myuchelys bellii (Gray 1844) – Western Saw-shelled Turtle, Bell‘s Turtle.

Abstract

Myuchelys bellii is an intermediate-sized short-necked freshwater turtle (Family Chelidae) with a range restricted to upland streams in the Namoi, Gwydir, and Border Rivers catchments of the Murray-Darling Basin, New South Wales and Queensland, Australia. Sexual size dimorphism is moderate, with adult males (up to 227 mm carapace length) smaller than females (up to 300 mm). The species occupies streams between 600 and 1100 m elevation that contain permanent pools deeper than about 2 m, frequently with granite boulders and bedrock, and often with underwater caverns formed by boulders, logs, and overhanging banks. In areas of lower water velocity, the typical substratum is coarse granitic sand overlain by fine silt, algal growth, and dense beds of macrophytes. The species has a nonspecialized omnivorous diet, which includes aquatic plants, algae, sponges, terrestrial fruits, aquatic insects, crayfish, and carrion. The species lays a single clutch of between 8 and 23 eggs per year in September-December and has one of the lowest reproductive outputs of any Australian chelid. Eggs hatch after 49-51 days, and hatchlings average 26.7 mm in carapace length. The species relies on aquatic respiration through cloacal bursae during inactive winter months to hibernate at depth, and has a crepuscular habit during the active months, using shallows and riffle zones for foraging at night. Threats include ongoing loss of riparian vegetation, loss of lotic habitat from water resource development and associated infrastructure, and physical modifications resulting from land clearing and livestock grazing, such as increased turbidity and infilling of deep pools. There is concern also for the impact of exotic nest predators, exotic fish, translocation of other native turtle species, and disease. No major conservation initiatives are currently directed at the species, but are planned under the draft recovery strategy of the NSW Office of Environment and Heritage. It is regarded as potentially vulnerable to extinction. DistriBution.-Australia. Restricted to upland streams of the Namoi, Gwydir, and Border Rivers catchments of the inland Murray-Darling Basin in northeastern New South Wales and extreme southeastern Queensland. synonymy.-Phrynops bellii Gray 1844, Hydraspis bellii, Elseya bellii, Wollumbinia bellii 1 , Wollumbinia bellii bellii 1 , Elseya latisternum bellii, Myuchelys bellii, Elseya dorriani Wells 2002 1 (nomen nudum), Wollumbinia bellii dorriani 1. suBspecies.-None currently recognized.