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Illustration of the Obdurodon tharalkooschild, a middle to late Cenozoic giant toothed platypus from the the World Heritage fossil deposits of Riversleigh, Australia.

A giant toothed platypus that lived in the middle to late Cenozoic era had powerful teeth (inset: the holotype, a first lower molar) that would have enabled it to kill prey such as lungfish and even small turtles.

Reconstruction by Peter Schouten

Christine Dell'Amore

National Geographic

Published November 4, 2013

What's cooler than a venomous, duck-billed mammal that lays eggs? A giant one—and that's just what researchers have found.

A newly discovered species of three-foot-long (one-meter-long) platypus, dubbed Obdurodon tharalkooschild, swam through freshwater pools in Australian forests about 5 to 15 million years ago, according to a new study. That's a much bigger critter than a modern-day platypus, which at 15 inches (38 centimeters) long is about the size of a small domestic cat.

Scientists fleshed out the animal based on a single tooth found several years ago in limestone collected from the fossil-rich Riversleigh World Heritage Area of northwest Queensland (map).

The limestone fossils were stowed in a cupboard and forgotten until study leader Rebecca Pian, a Ph.D. student at Columbia University in New York City, pulled them out in 2012 while studying at Australia's University of New South Wales.

One tooth struck her as odd: It was bigger than any known platypus tooth. After closer study, "I said, 'Wait a second, not only is it quite big, it's quite different as well,'" Pian remembers. When she showed it to study co-author Mike Archer, he immediately agreed it was new.

For instance, the tooth clearly had the unique shape known to belong only to platypus teeth. But it also had bumps and ridges never before seen in the group. To estimate the size of the animal the tooth came from, Pian and colleagues compared the tooth with other platypus teeth and made a rough extrapolation of the size of the new species.

It was bigger than any platypus known before. The team had just shaken up platypus evolution.

Filling in the Gaps

The ancient platypus belongs to a tiny group of egg-laying mammals called monotremes, of which only three modern species remain: the platypus and two species of echidna, all of which are found in Australia and New Guinea. (See "Platypus Genome Reveals Secrets of Mammal Evolution.")

Only four extinct platypus species have been discovered, each in different periods of time, leading scientists to believe that either there are huge gaps in the fossil record or the platypus family tree is simply not very diverse. Part of the problem is that most of the time, only the teeth with their hardy enamel survive the wear and tear of time.

Now, with the discovery of O. tharalkooschild, researchers know that "the evolution of the platypus is potentially more complicated than we thought," said Pian, whose study was published in the November issue of the Journal of Vertebrate Paleontology.

That's because its larger size and possibly more carnivorous teeth suggest it had a different diet from other platypuses—which mostly eat soft invertebrates—possibly taking on bigger prey such as frogs, Pian said. Such a hearty diet may have also been why the newfound platypus was so big, she added.

The fact that the ancient species had such a big tooth was surprising, since older platypus fossils have suggested they evolved smaller and fewer teeth over time. Today's platypus, for example, only has teeth as a youngster. Later in life, an adult chews its soft prey using horny pads in its mouth. (Watch a video about platypus evolution.)

It's even possible the new fossil platypus was part of a now-extinct side branch of the main platypus lineage.

Solid Research

"This seems like a solid piece of research—if I'd found it, I'd have given it a new name as well," noted Timothy Rowe, director of the Vertebrate Paleontology Laboratory at the University of Texas, Austin.

Platypus teeth are so "exceedingly unique" that it's clear the new tooth is from a platypus, added Rowe, who wasn't involved in the new study.

The paleontologist also said the finding reinforces that "we don't really know" a lot about the evolution of platypuses and echidna.

But, he said, "we're starting to fill in some of the gaps, and that's always a happy thing."

Follow Christine Dell'Amore on Twitter and Google+.

72 comments
Gloria A.
Gloria A.

So cool! Animals are like so evolutionary and COOL! Especially on how they evolved over time. Well, but I have not actually seen a real, live platypus before. Unless you count on videos and such. I wish I could see one real soon! I lurv animals!!!

Xiaohan Sun
Xiaohan Sun

Amazing world.The powerful world can creat many kinds of animals.We should protect them.They are one of member in the world.

N A Creator
N A Creator

I'm looking forward to seeing photographs of the next amazing creature that has not yet been discovered.

Jerold Te
Jerold Te

This is so cool, Platypus was the king of the river 5-15 million years ago

Grace Cole
Grace Cole

this platy is so scary is has talons and everything


Grace Cole
Grace Cole

hey Grace H  I am doing this for a current event also thats boss!! sorry guys im kinda hyped this is so cool and im in a good part in my book ......... i am SUCH A NERD


Yitzchak Fried
Yitzchak Fried

wow very cool. are there any follow up studies? It'd be great if National Geographic posted relevant links to articles bearing further analysis or detail. 

Grace H
Grace H

this site asked me three times for my email and password to get on here. I think it is kinda ridiculous because now it is just one more password i have to remember. That is just my opinion. But this article is pretty darn cool, I'm gonna do it for my current event for school :)

Jonathan Hernandez
Jonathan Hernandez

i think this is true but at the same time i think its fake can you post of the body and then we will see if bigger than the other platypus 

Harry Mikolowski
Harry Mikolowski

how do you know that they lived 5-15 million years ago and not 500-1000 years ago & how do know that the tooth found is even from a platypus and some other type of creature

Ray Tan
Ray Tan

seems like they were eating turtles like crackers

Yasuo Miyagi
Yasuo Miyagi

That's cool. Old  platypus was big and had teeth.

Jim Lindstrom
Jim Lindstrom

It is interesting to be aware of the diversity of life before homo "sapiens" came along

Charles Lee
Charles Lee

@Zebedee C. Please take your religious nonsense talk to creationist museum in Kentucky. This is serious scientific website and article about Evolution not "creationism delusion"

Tim Morris
Tim Morris

@Zebedee C.  Or, conversely, of natures' brilliance, regardless of any human concept of a deity. Religious ideas in my opinion, belittle the true scope and majesty of nature.

ADVENTURE MAN C.
ADVENTURE MAN C.

@Christian Senra If you don't want to leave home I'd recommend  Stratford, it's a online university

Willem Cousineau
Willem Cousineau

@Grace Cole A current event for school? If so, what school do you go to? I'm not a stalker I am just using this for a current event too.

Grace Cole
Grace Cole

@Grace H Hi I think its cool that we are both doing a current event cuz' i dunno just there are so many school assighnments out there and we have the same one and we are using this one..... cool chiz

anne boad
anne boad

@Grace H me too! Had to set up a new email account and jump through all kind of hoops just to read a couple of new articles each week.

Ventura Calderon Parada
Ventura Calderon Parada

Same here. Wouldn't take my old password; when I tried a new one, it was rejected over and over, even though it fit their criteria. When I finally give up, I find out I'm logged in. It shouldn't be a mystery tour to get into this place...or should it? Hmmm.

Tim Morris
Tim Morris

@Harry Mikolowski  Mammal teeth are particularly diagnostic, meaning you can tell what kind of animal, even just from one tooth. Riversleigh fossils are usually encased in hard limestone, if you can find stone that forms so hard in only 500 years, I'll eat my hat.

Kristaps Eglitis
Kristaps Eglitis

@Harry Mikolowski The same way they could tell how old are dinosaurs (And separate what time each of them lived) and other prehistoric species - Carbon Dating.

badrun n.
badrun n.

@Ventura Calderon Parada mine didn't ask for anything i think it saved my password or im just thinking things

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