Fossil Reveals New Species of Ancient Platypus

Posted November 5th, 2013 at 7:15 pm (UTC-4)
1 comment

Obdurodon tharalkooschild, a middle to late Cenozoic giant toothed platypus.  Fossil found in the World Heritage fossil deposits of Riversleigh, Australia. Unlike today's platypus this ancient species had teeth - see inset. (Peter Schouten)

Obdurodon tharalkooschild, a middle to late Cenozoic giant toothed platypus. Unlike today’s platypus, this ancient species had teeth (see inset). (Peter Schouten)

Australian scientists say they’ve found the fossil of a new species of  giant platypus that walked the Earth between 5 and 15 million years ago.

Up until now, the fossil record of the platypus indicated that only one species of the animal lived on Earth at any one time. The new study suggests this new extinct giant platypus species, called Obdurodon tharalkooschild, is a side-branch of the platypus family, rather than its direct ancestor.

The platypus is a mammal with a duck-like bill, thick fur that’s much like an otter’s, and a tail similar to a beaver’s. It has webbed feet and reproduces by laying eggs rather than giving birth like other mammals.

The animal was so odd that in 1798 when Captain John Hunter, then the governor of New South Wales, Australia, sent a pelt of a platypus along a sketch of the animal to scientists in Great Britain, the British researchers at first thought it was a joke or a hoax.

The Australian researchers were able to identify this new species of platypus from a single fossilized tooth found in the Riversleigh World Heritage Area of northwest Queensland, Australia.

Monotremes (platypuses and echidnas) are the last remnant of an ancient radiation of mammals unique to the southern continents,” said Rebecca Pian, lead author of the study. “A new platypus species, even one that is highly incomplete, is a very important aid in developing understanding about these fascinating mammals.”

The fossilized tooth’s size leads researchers to believe this ancient platypus was about a meter in length, two times the length of today’s platypus. Today, the male platypus grows to a length of about 50 cm while females grow to about 43 cm in length.

A modern day platypus swimming underwater at the Sydney Aquarium (wehunts via Flickr/Creative Commons)

A modern day platypus swimming underwater at the Sydney Aquarium (wehunts via Flickr/Creative Commons)

“Like other platypuses, it was probably a mostly aquatic mammal and would have lived in and around the freshwater pools in the forests that covered the Riversleigh area millions of years ago,” said Dr. Suzanne Hand of the University of New South Wales, a co-author of the study.

The ancient Obdurodon tharalkooschild was able to eat its prey with a set of well-developed teeth, unlike today’s platypus which has horny pads in its mouth instead.

The extinct platypus probably ate a varied menu that included not only crayfish and other freshwater crustaceans, but also small vertebrates such as lungfish, frogs, and small turtles.

The researchers named  the prehistoric animal Obdurodon, Greek for “lasting (obdurate) tooth,”  because its teeth are unlike today’s platypus species.  Tharalkooschild was given in honor of a story told by Indigenous Australians about the creation and origin of the platypus.

Rick Pantaleo
Rick Pantaleo maintains the Science World blog and writes stories for VOA’s web and radio on a variety of science, technology and health topics. He also occasionally appears on various VOA programs to talk about the latest scientific news. Rick joined VOA in 1992 after a 20 year career in commercial broadcasting.

One response to “Fossil Reveals New Species of Ancient Platypus”

  1. Cranksy (USA) says:

    Although I know next to nothing about naming new species, the name given to this one seems classy. I think names sometimes are chosen for more ego gratifying and personal reasons. There does seem to be a fair(?) amount of speculation about this creature. I am grateful for this post for providing me also with known facts.