While today crocodiles follow a fairly rigid semi-aquatic body template without too much room for variation, in the past there have been many different types of (often bizarre) specially designed crocs that look very different to those of today. One design that has consistantly reappeared throughout the fossil record was that of the terrestrial running crocodile. Quinkana (whose name comes from the Aboriginal term 'Quinkans', ghostly mythological beings) was one of the last to have eisted. It lived in northern and western Australia.
Quinkana was a fairly long lived genus. It's earliest known members lived some 5 million years ago at the end of the Miocene, while the last of it's kind survived up until 40,000 years ago (the Pleistocene). While the tail end of Quinkana's reign may have overlapped with the first Aboriginal people arriving in Australia, no direct evidence to suggest that they ever encountered each other exists.
Australia did however have no shortage of large reptiles at this time. In addition to Quinkana there was also Meiolania (the largest land based turtle known), megalania (the giant monitor lizard) and Wonambi (a primitive, but massive snake) among others. The hot and dry climates of Australia would have favoured such reptiles as they typically thrive in such environments due to their ability to conserve energy better and eat much less than warm blooded animals.
First discovered in 1981, Quinkana showed many features commonly seen in land based crocodiles; long and powerful legs, a broad head and serrated teeth that curved backwards. All of these adaptations suggest it was built for chasing down prey across land, unlike modern crocs which are adapted to spend most of their time in water and are comparitively slow when moving across land.
Quinkana's size varied from species to species. The largest was Q. fortirostrum (the latest surviving member of the genus) which may have exceeded 5 meters (possibly as much as seven) in lenght, rivaling the giant megalania (Varanus priscus) in size. Their ranges appear to have overlapped too, conjuring up images of intense battles over food/territory. However, as with humans, there is no solid evidence of direct confrontation between the two. It has been suggested that megalania was a semi-aquatic hunter, ironically occupying the niche that modern crocodiles occupy, while Quinkana roamed dryer areas. The two may never have met at all.
While Q. fortirostrum was a giant, most species of Quinkana (meboldi, timara, barbarra) were of more modest size, between 2 and 3 meters in lenght, putting them within the size range of the average modern crocodile.
(left: megalania, right: Quinkana)
Quinkana may have fed on Diprotodon, a previous creature of the week.