Riversleigh rainforest koala facts for kids

Quick facts for kids Riversleigh rainforest koala Temporal range: Early-middle Miocene
Restoration of N. greystanesi
Scientific classification
Genus:	Nimiokoala
Species:	greystanesi

The Riversleigh rainforest koala (Nimiokoala greystanesi) was an extinct marsupial. It was a close relative of the koalas we know today. This ancient koala lived in northwestern Queensland, Australia. It roamed the Earth during the early to middle Miocene epoch, which was about 23 to 16 million years ago.

Compared to modern koalas, the Riversleigh rainforest koala was much smaller. It was one of the smallest members of the koala family, called Phascolarctidae. Scientists believe it died out because of climate change. The area where it lived became much drier. We don't know exactly what it ate, but it likely had a more varied diet than today's koalas.

What's in a Name?

The name Nimiokoala comes from a Latin word, Nimio, which means "excessive." This refers to its complex teeth, which were more detailed than those of other koala species. The second part of its name, greystanesi, was chosen to honor Greystanes High School.

How We Know About It

Scientists have found many fossils of extinct koalas in a place called Riversleigh. As of 2013, 55 of these fossils belong to the Riversleigh rainforest koala.

So far, researchers have found a partial skull, several lower jaws, and many separate teeth. These fossils have helped scientists figure out what the animal's teeth looked like. The species was officially named in 1997. The main fossil, called a holotype, is kept at the Queensland Museum.

What Did It Look Like?

Since scientists haven't found a full skeleton, they estimate the size of the Riversleigh rainforest koala from its teeth. It was probably about 25–30 cm (9.8-11.8 in) long. It weighed around 3.5 kg (7.7 lb). This means it was only about one-third the size of a modern koala! It was also more than 10 times smaller than the biggest known ancient koala, Phascolarctos yorkensis.

Its face was different from modern koalas. It had a snout that looked more like a possum. Its teeth were crescent-shaped with many bumps and sharp edges for shearing food. The fossilized skull also shows that it had large eye sockets and very big ear bones.

Life in the Ancient Rainforest

Millions of years ago, the Riversleigh area was a lush tropical forest. There were also open areas with karst soil near streams and lakes. As the climate changed and became drier, smaller koala species, including the Riversleigh rainforest koala, died out.

Because Nimiokoala was so small, it needed to eat a lot to get enough energy. Its large eye sockets suggest it had good night vision. These features mean it was likely much more active than today's koalas. The structure of its ear bones was similar to modern koalas. Its large ear bones also suggest it could hear and use low-frequency sounds. These sounds might have been used to communicate or find mates.

See also

In Spanish: Nimiokoala greystanesi para niños