Paleontologist from the University of New South Wales have discovered that the fossil remains excavated in the Riversleigh World Heritage Area of remote north-western Queensland belongs to a tiny new species of marsupial lions that lived in the lush rainforest of Northern Australia about 18 million years ago.

The new specie, dubbed as Microleo attenboroughi due to its size and in honor of famous broadcaster and naturalist Sir David Attenborough, was as big as ringtail possum, weighing about 600 grams.

According to a paper published in the journal Palaeontologia Electronica, the small marsupial lion was much smaller in size compared to the other member of the marsupial lion family, including the famous lion-sized Thylacoleo carnifex.

"Despite its relatively small size compared with the Pleistocene Thylacoleo carnifex -- the last surviving megafaunal marsupial lion -- the new species was one of the larger flesh-eaters existing in its ancient community of rainforest creatures at Riversleigh," said Mike Archer, a professor from the UNSW and member of the research team, in a statement.

Due to its relatively small size, the researchers believe that the tiny marsupial lion most likely to fed on small insects, lizards and birds. These tiny carnivores might also scamper among tree tops to avoid becoming a prey for its larger relatives.

The discovery was made after the researchers found part of skull and teeth from a limestone deposit believed to have formed in a pool within a rainforest landscape about 19 million years ago, during the Miocene.

Like all the members of the marsupial carnivore family, Microleo attenboroughi has a dentition including an elongate, lethally sharp, knife-like premolar in front of the basined molars.

National Public Radio reported that M. attenboroughi is the ninth and smallest species of marsupial lions excavated and discovered from the Riversleigh World Heritage fossil site.

Marsupial lions, despite of the name, is not related with modern lions. They are more closely linked to modern marsupials such as koalas. Scientists named them lion to refer to their status as an ancient hunter and dangerous carnivores.