Featured Research

from universities, journals, and other organizations

Primitive Mouse-Like Creature May Be Ancestral Mother Of Australia's Unusual Pouched Mammals

Date:
March 26, 2008
Source:
University of New South Wales
Summary:
A new study has confirmed that a primitive mouse-like creature that lived 55 million years ago (called Djarthia) is also a primitive relative of the small marsupial known as the Monito del Monte -- or "little mountain monkey" -- from the dense humid forests of Chile and Argentina.

The Monito del Monte (Dromiciops gliroides)
Credit: Image courtesy of University of New South Wales

They are separated by a vast ocean and by millions of years, but tiny prehistoric bones found on an Australian farm have been directly linked to a strange and secretive little animal that lives today in the southern rainforests of South America.

The fossilised ankle and ear bones are those of Australia's earliest known marsupial, Djarthia, a primitive mouse-like creature that lived 55 million years ago. It is a kind of Australian Eve, possibly the mother of all the continent's unusual pouched mammals, such as kangaroos, koalas, possums and wombats.

But a new study has confirmed that Djarthia is also a primitive relative of the small marsupial known as the Monito del Monte -- or "little mountain monkey" -- from the dense humid forests of Chile and Argentina.

Although scientists now generally agree that marsupials found their way to Australia from South America, the new finding suggests that the Monito del Monte may subsequently have made the return journey and is indeed a living fossil, the last of a lineage that can be traced back to Djarthia.

The bones were collected from the Tingamarra fossil site near Murgon, in Queensland, and have been studied by a research team led by Mr Robin Beck, a doctoral student in palaeontology at the University of New South Wales, in Sydney.

"It's now accepted that Australia's marsupials are the result of dispersal from South America via Antarctica, when the three continents were joined as part of the super-continent Gondwana," Mr Beck says.

"We know from other fossils that marsupials were present in South America at least five million years before Djarthia, which is by far Australia's oldest and most primitive marsupial fossil.

"Scientists already suspected that the Monito del Monte is more closely related to Australia's marsupials than to South America's, but its exact origins have been controversial. Until now, we only knew Djarthia from isolated teeth, which weren't enough to tell us whether it was related to the Monito del Monte or not."

"The fossil ankle and ear bones of Djarthia make it clear that the Monito del Monte descends from a Djarthia-like ancestor, and so probably returned to South America from Australia before Gondwana broke up. The continents have been separated by deep ocean since about 40 million years ago."

Like the Monito del Monte, Djarthia was a little larger than a mouse and, likewise, its ankle bones show adaptations for climbing trees. It probably had a similar diet as well: the Monito del Monte eats insects and other small invertebrates and some fruits.

The Monito del Monte is nocturnal and its agility and prehensile tail make it an excellent climber. Females carry up to five young in a well-developed pouch.

Journal reference: Beck RMD, Godthelp H, Weisbecker V, Archer M, Hand SJ (2008) Australia's Oldest Marsupial Fossils and their Biogeographical Implications. PLoS One 3(3): e1858. doi:10.1371/journal.pone.0001858


Story Source:

The above story is based on materials provided by University of New South Wales. Note: Materials may be edited for content and length.


Cite This Page:

University of New South Wales. "Primitive Mouse-Like Creature May Be Ancestral Mother Of Australia's Unusual Pouched Mammals." ScienceDaily. ScienceDaily, 26 March 2008. <www.sciencedaily.com/releases/2008/03/080325203453.htm>.
University of New South Wales. (2008, March 26). Primitive Mouse-Like Creature May Be Ancestral Mother Of Australia's Unusual Pouched Mammals. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2008/03/080325203453.htm
University of New South Wales. "Primitive Mouse-Like Creature May Be Ancestral Mother Of Australia's Unusual Pouched Mammals." ScienceDaily. www.sciencedaily.com/releases/2008/03/080325203453.htm (accessed July 25, 2014).

Share This




More Fossils & Ruins News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Mint Gives JFK Coin a Face-Lift

Mint Gives JFK Coin a Face-Lift

AP (July 24, 2014) The U.S. Mint has re-designed the John F. Kennedy half dollar coin to better match the former president's likeness. (July 24) Video provided by AP
Powered by NewsLook.com
Raw: MD Church Built in 1773 Ravaged by Fire

Raw: MD Church Built in 1773 Ravaged by Fire

AP (July 22, 2014) Authorities say a 241-year-old church on the National Register of Historic Places has been ravaged by fire in Maryland. (July 22) Video provided by AP
Powered by NewsLook.com
Neil Armstrong's Post-Apollo 11 Life

Neil Armstrong's Post-Apollo 11 Life

Newsy (July 19, 2014) Neil Armstrong gained international fame after becoming the first man to walk on the moon in 1969. But what was his life like after the historic trip? Video provided by Newsy
Powered by NewsLook.com
A Centuries' Old British Tradition Is Far from a Swan Song

A Centuries' Old British Tradition Is Far from a Swan Song

AFP (July 19, 2014) As if it weren't enough that the Queen is the Sovereign of the UK and 15 other Commonwealth realms, she is also the owner of all Britain's unmarked swans. Duration: 02:18 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins