Mary River turtle (Elusor macrurus) lives in Mary /Moonaboola River, Queensland, Australia. They mostly eat aquatic plants, but sometimes seeds, fruits and insect larvae. This turtle has a unique and distinct appearance that resembles a punk, which is due to the green algae growing from its head and body. This algae helps the turtle to blend in with its surroundings and hide from predators in its aquatic habitat. The turtle also has two long and fleshy protrusions known as barbels on its chin that help it detect and sense its environment.
In addition to its unusual appearance, the Mary River turtle also has a neat trick up its sleeve — or rather, its butt.
“It can spend days at a time submerged, managing to ‘breathe’ underwater — a feat achieved by very few reptiles — through specialised organs inside its cloaca [an orifice found mostly in non-mammalian vertebrates for intestinal, urinary and genital tracts],” Rikki Gumbs, a researcher at the EDGE of Existence programme, a conservation initiative focusing on unique and overlooked species, told Live Science in an email.
Some freshwater turtles use their skin for aquatic respiration, but others, like the Mary River turtle, have cloacal glands that allow them to be submerged for longer periods. These glands, known as cloacal bursae, are covered with papillae, which are tiny structures lining the walls of the bursae. Oxygen from the water diffuses across the papillae and into the turtle’s bloodstream. As a result, the Mary River turtle can stay underwater for up to 72 hours.
The Mary River turtle is also unique: No other turtle is closely related to it. “It is the only surviving species in its genus,” Gumbs said. “It is thought the ancestors of the Mary River turtle diverged from all other living turtle lineages more than 18 million years ago — several million years before our ancestors and those of the orangutan parted ways.”