It’s time for another turtle, but you may only have heard of it if you’re in the punk scene.
This is the Mary River turtle, aka the punk turtle on the internet, because it grows a green algae mohawk in its Australian river home. Unfortunately, scientists don’t tend to call it ‘punk turtle’ and instead revert to the scientific name Elusor macrurus.
As the name ‘Mary River turtle’ suggests, you can find these turtles in the Mary River in southeast Queensland, Australia. In fact, this is the only place in the world where you can find them: Mary River turtles are endemic to the Mary River and are found nowhere else on Earth.
Recent discovery
Mary River turtles are one of Australia’s largest turtles: females grow to be 34 cm (13 in) long, and males can get 42 cm (16.5 in) long. But even with this large shell, they still managed to slip under the radar of scientists for a while. This species was first described by science in 1994, making the Mary River turtle scientifically the same age as me!
How did such a giant turtle evade scientists for so long?
Two words: pet trade.
In the 1960s and 1970s, Mary River turtles were sold as hatchlings in pet shops throughout Victoria. Hatchlings are tiny, with a shell that is only 2 – 3 centimeters long; due to their small size, these hatchlings were sold as ‘penny-turtles.’
At some point, turtle researcher John Cann noticed that these penny-turtles were unlike any other turtle hatchlings he had seen before. He spent 20 years trying to find out where pet shops were getting the turtles but kept hitting dead ends since poachers aren’t typically very open about where they source their animals. But with the wildlife pet trade ending in the 1970s, Cann soon got a lead as to where the turtles lived.
Finally, in 1994, Cann located the source of the turtles: the Mary River. He and American researcher John Leggler described the turtle and cemented its place in the written scientific records.
Evolutionarily old
Even though we may have only formally discovered Mary River turtles recently, they have been around for a long time. This species diverged from all other living species 40 million years ago. In comparison, we diverged from our closest living relatives, chimps and bonobos, less than 10 million years ago.
The Mary River turtle is the only living member of its genus, a relic from the time of the dinosaurs.
Unique turtle traits
Because the Mary River turtle is so evolutionarily old, it has traits not seen in modern turtles.
For instance, they have little fleshy bits under their chins! These tubercles act like feelers, letting the Mary River turtle search easily search for food on the river floor.
Male Mary River turtles also have incredibly long tails – their tail can be 70% of their shell length! The tails of both males and females are also interesting because they are the only turtles in the world with vertebrae that taper down to the tip of their tails.
Butt breathers
No, I’m not being rude! Mary River turtles really can breathe from their butt.
Unlike most turtles, Mary River turtles have two ways to breathe: through their mouth and through their cloaca. You may have heard me talk about the cloaca before – it’s the all-in-one hole amphibians, reptiles, and some fishes use for pooping, peeing, and reproducing.
Mary River turtles have added breathing to this list of things a cloaca can do. Their cloaca has specialized, gill-like structures that can extract oxygen from the surrounding water.
Since they don’t have to come out of the water to breathe, Mary River turtles can stay submerged for long periods. One young male in optimal conditions (i.e., the perfect temperature and lots of oxygen in the water) was able to stay underwater for 2.5 days!
Endangered
Unfortunately, there aren’t many Mary River turtles left. The Zoological Society of London ranks them 30th out of 50 on their Evolutionarily Distinct and Globally Endangered (EDGE) list. This list ranks species based on how close they are to extinction and their evolutionary uniqueness.
Part of the problem is that Mary River turtles only live in the Mary River. Any changes to the river, from invasive plants and animals to pollution, can make it harder for them to survive.
The pet trade also did a number on the species. Between 1960 and 1974, up to 12,000 eggs were collected annually from the Mary River. This decimated the number of young Mary River turtles around, so the current population is composed of older individuals.
Luckily, environmentalist work has helped increase the number of hatchlings in the Mary River. Unfortunately, that doesn’t seem to be enough. New research suggests that no hatchlings survive in the river for more than six months; by that point, they’ve almost certainly been eaten by a fish like the fork-tailed catfish.
This is an excellent example of why conservation programs need constant monitoring throughout all stages of the program. As the Mary River turtles show us, just because you match doesn’t mean you’ll make it to adulthood.
Hopefully, researchers will find ways to help this species survive in the future!
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