No other mammal currently known has such an unusual crushing premolar, but similar teeth are seen in Australian lizards that feed on snails, suggesting that malleodectids may have had a similar diet. Malleodectids, which were about the size of ferret, are known only from 10-15 million year old fossils from the Riversleigh World Heritage Area in far northern Australia.
Very incomplete malleodectid fossils were described in 2011, but the discovery of a new fossil jawbone has now revealed unique features indicating a previously unknown marsupial family.
The research is published today in the Scientific Reports arm of the journal Nature.
Malleodectids were probably related to living Australian carnivorous marsupials such as quolls, the Tasmanian Devil and the marsupial anteater or numbat, as well as the recently extinct thylacine or Tasmanian tiger. However, malleodectids represent a lineage of marsupials that has been distinct since at least 23 million years ago.