Emydura macquarii (Gray, 1830)

Species Nomenclature and Aquatic Habit

The Macquarie River turtle, scientifically named Emydura macquarii (Gray, 1830), is almost entirely aquatic.

Shell and Plastron Structure

Its intergular plate extends to the front edge of its shell, and its plastrons are shaped with cut-away sections.

Locomotion Adaptation

This structure lets the turtle's legs move freely, allowing it to swim powerfully.

Geographic Range Overview

Emydura macquarii has a broad geographic range across multiple Australian states.

Native Distribution Details

It occurs in coastal Queensland rivers, the Cooper Creek ecosystem, Fraser Island, Brisbane, the Macquarie River basin and all of its major tributaries, a number of coastal rivers along the New South Wales coast, northern Victoria, South Australia, the billabongs and channels of Cooper Creek, and along the Murray River.

Introduced Populations

Introduced populations of this species are also present in the Adelaide city area.

Nesting Period

The Macquarie River turtle nests from October to early January.

Egg Laying Behavior

Females may lay multiple clutches of eggs, in nests they excavate in riverbanks.

Sex Determination System

This species uses the XY sex-determination system, making it one of the few turtle species with a genetic sex-determination mechanism.

Sex Chromosome Type

Its X and Y chromosomes are macrochromosomes.

Sex Chromosome Comparison

This differs from most other genetically sex-determined turtles, including its close relative Chelodina longicollis, which has sex microchromosomes.

Sex Chromosome Origin Hypothesis

It has been hypothesised that this turtle's sex chromosomes formed when an ancestral Y microchromosome translocated onto an autosome.

Gender Identification

It is often difficult to identify the gender of young Macquarie River turtles, but gender becomes easier to distinguish as the turtle grows.