Chelodina (Chelydera) expansa, commonly known as the broad-shelled river turtle or the broad-shelled snake-necked turtle, is a pleurodiran freshwater turtle and is the largest of the long-necked turtles. The broad-shelled river turtle is one of the oldest-maturing and longest-living species of freshwater turtles in existence and occurs in wide sympatry with Emydura macquarii and Chelodina longicollis. C. expansa is listed as ‘vulnerable’ in South Australia and ‘threatened’ in Victoria. Distribution and habitat Broad-shelled river turtles are found throughout the Murray-Darling basin of southeastern Australia. A number of distinct populations are also found across areas of central and coastal Queensland. C. expansa is mostly found in turbid waters of depths greater than three metres. It is mostly a river turtle, generally inhabiting permanent streams but is also found in oxbows, ponds in floodplains, backwaters, and swamps across its distributed region. The broad-shelled river turtle will tend to inhabit environments that are undisturbed and have moderate vegetation cover for nest construction. The turtle has shown a preference of aquatic habitats in structured environments, where submerged logs, root systems and dead trees occur. Factors such as shelter from predators and food availability may influence the habitat preference of C. expansa. Seasonal changes including water level and flow may also influence the selected the habitat. Description The broad-shelled river turtle has a broad, oval and flattened shell with a length of around 50 cm. The carapace length is often greater in females than males. The turtle has a rich brown to blackish-brown carapace above, typically displaying fine dark flecks or reticulations, and a whitish or cream-colored belly. The plastron is narrow and the shell does not display any noticeable expansion anteriorly. The shell is usually twice as long as wide and is broadest at the level of the bridge. The head is broad and highly depressed and the eyes are directly dorsolateral. When extended, the neck may be longer than the carapace. Behaviour The broad-shelled river turtle is mostly active from Austral spring season (October) through to early autumn (April). The species tends to decrease in movement and feeding over the cooler winter months. C. expansa is described to also show head bobbing and self-grooming actions.<ref name="Legler 1978" Chelodina expansa spends most of its time in water. During periods when water levels are low, C. expansa will traverse over land to find other water sources. The turtle may also bury itself into mud and