The Mary River turtle, Elusor macrurus, is an endangered short-necked turtle that inhabits the Mary River in South-East Queensland, Australia. In the 1960s and 1970s, they were popular as pets in Australia, with about 15,000 sent to shops every year during a ten-year period. They were originally known as the "Penny Turtle" or "Pet Shop Turtle". Elusor is a monotypic genus representing a very old lineage of turtles that has all but disappeared from the evolutionary history of Australia.
Chris Van Wyk
The Mary River turtle is one of Australia's largest turtles. Specimens in excess of 50 cm carapace
length have been recorded. Hatchlings have a straight carapace length
of 2–3.5 cm. Adult Mary River turtles have an elongated, streamlined
carapace that can be plain in colour or intricately patterned. Overall
colour can vary from rusty red to brown and almost black. The plastron
varies from cream to pale pink. The skin colouration is similar to that
of the shell and often has salmon pink present on the tail and limbs.
The iris can be pale blue. Mary River turtles use bimodal respiration,
and are therefore capable of absorbing oxygen via the cloaca whilst underwater. However, they do regularly come to the surface to breathe air in the usual way.
Chris Van Wyk
A unique feature of male Mary River turtles is the tail, which can
measure almost two-thirds of the carapace length. The tail has haemal arches,
a feature lost in all other modern turtles. It is probably a derived
feature but its function is not understood. Another unique feature is
the exceptionally long barbels under the mandible.
Proportionately, the Mary River turtle has the smallest head and
largest hind feet of all the species within the catchment, which
contributes to its distinction of being the fastest swimmer. Wikipedia