Koolasuchus

*Koolasuchus cleelandi*

***Koolasuchus*** ( Kool’s crocodile) was a genus large Cretaceous amphibians that lived on the continent of Australia. They where a carnivores whose diet included turtles, clams and crayfish.

*Koolasuchus* species where members of the Temnospondyli order of amphibians and specifically of the Chigutisauridae family. They lived in the rift valley where southern Australia was starting to split from Antarctica, and perhaps elsewhere. It is notable both because it was one of the largest temnospondyls, and because they survived long after its cousins further north had become extinct. It was a large temnospondyl about the size of a large, modern day crocodile.

Since crocodiles and other crocodylimorphs weren't able to live in Antarctica (even without the ice caps), giant amphibians remained. They speculated to being able to prey upon small to medium sized dinosaurs, such as *Leallynasaura*.

They lived in Australia 137 to 105 MYA. It was about 4.5 to 5 metres (14.5 - 15 ft) long and weighed 500 kg.

Koolasuchus is one of the last temnospondyl species and larger amphibians to survive up into the Cretaceous.

Most temnospondyl lived and perished through the Carboniferous, Permian, and Triassic. Koolasuchus was probably one of the more successful species of his family of amphibians.

In January 13, 2022, Koolasuchus cleelandi was adopted as a fossil emblem for the state of Victoria, Australia.

## Description

Competition with phytosaurs during the Late Triassic, and later, crocodilians is believed to have contributed to the general decline of the temnospondyl order. At this point in time, Australia was within the Antarctic Circle, and had a climate too cold for crocodiles, protecting them from this competition. *Koolasuchus* could survive in this colder climate because, like modern salamanders, it is thought to have hibernated under the ice in ponds during the winter.

*Koolasuchus* shared with older temnospondyls a very wide, heavy skull (50 centimeters/20 inch wide) which contrasted with its small weak body and limbs. Like modern crocodiles, *Koolasuchus* had its eyes on the top of its head. This suggests that it was an ambush hunter. Around 5 meters (16 ft) long but only 30cm (1 ft) high, and with a weight of more than half a ton, it would have been able to hunt mammals or small dinosaurs who drank from the shallow swamps and rivers it lived in to supplement its diet. Due to its extremely large head and mouth, it may have been able to capture fish and shellfish by lying in wait and suddenly opening its mouth, sucking in water and its victim. This is a feeding style similar to that of the unrelated modern-day giant salamanders of Asia.

*Koolasuchus* is named for the palaeontologist Lesley Kool and geologist Mike Cleeland. Its remains were found in 1989 near San Remo, Victoria, Australia.

Koolasuchus was actually a rather large amphibian for his classification. A flat head lined with teeth made it easy for this predator to grip prey, either dragging smaller animals into the water to drown them or snapping up fish as well as any other similiar sized aquatic vertabrae.

A tapering tail was lined with a small fleshy-ridge, probably like the Spinosaurus's, a streamlined fin-like lobe for swimming through rivers. It walked on four stubby legs, and probably wasn't a threat to any dinosaur on land, but in the water, it was thought to be a lethal animal.

## History

*Koolasuchus* was named in 1997 from the Aptian Strzelecki Group of the Wonthaggi Formation in Victoria. It is known from four fragments of the lower jaw and several postcranial bones, including ribs, vertebrae, a fibula, and parts of the pectoral girdle. A jawbone was found in 1978 in a fossil site known from the punch bowl near the town of San Remo. Later specimens were found in 1989 on the nearby Rowell's Beach.

A partial skull is also known but has not been fully prepared. *Koolasuchus* was named for the paleontologist Lesly Kool. The name is also a pun on the word "cool" in reference to the cold climate of its environment. The type species K. cleelandi is named after geologist Mike Cleeland.

## Paleobiology

Little is known about the lifestyle of Koolasuchus, it's known that the amphibian adapted to colder water and weather conditions of Southern Pole; and often thought being an active predator for the smaller to medium sized animals within its habitat.

## Appearance in other media

### *Jurassic Park*

* *Koolasuchus* appeared in Jurassic Park: Builder as a limited edition aquatic creature. It uses the *Dakosaurus*, *Geosaurus*, and *Metriorhynchus* animations even though they are unrelated, and share almost no anatomical similarities. Furthemore it is inaccurately portrayed as a saltwater-loving marine animal, while in reality it wouldn't survive due to being a freshwater-loving terrestrial amphibian.
* *Koolasuchus* appeared in Jurassic World: The Game as a rare amphibian.
* *Koolasuchus* appeared in the mobile game, Jurassic World: Alive as an Epic amphibian. It also has a Gen 2 version, which is a Rare. The *Koolasuchus* can be fused for the Koolabourgania, which in turn is for the Geminitian.

## References

* https://www.academia.edu/21856327
* https://web.archive.org/web/20080220004845/http://www.geocities.com/dannsdinosaurs/non-rept.html
* https://web.archive.org/web/20110719145945/http://www.envs.emory.edu/faculty/MARTIN/ResearchDocs/Dinosaur\_burrows\_2009.pdf
* https://museumsvictoria.com.au/media-releases/victorias-kool-new-state-fossil-emblem-koolasuchus-cleelandi/
* https://blog.everythingdinosaur.co.uk/blog/\_archives/2022/01/14/koolasuchus-becomes-the-state-fossil-of-victoria.html
* https://www.abc.net.au/news/2022-01-16/victoria-fossil-emblem-kkoolasuchus-cleelandi-/100757650
* https://www.newdinosaurs.com/koolasuchus/
* https://www.mindat.org/taxon-P251484.html
* https://www.researchgate.net/publication/233303962\_An\_Early\_Cretaceous\_labyrinthodont
* https://www.researchgate.net/publication/225676198\_Temnospondyl\_amphibians\_from\_the\_Jurassic\_of\_the\_Southern\_Junggar\_Basin\_NW\_China
* https://www.researchgate.net/publication/233211575\_Postcranial\_skeleton\_of\_a\_brachyopoid\_Amphibia\_Temnospondyli\_from\_the\_Triassic\_of\_Mendoza\_Argentina
* https://www.sciencedirect.com/science/article/abs/pii/S019566710900072X?via%3Dihub
* https://pubs.geoscienceworld.org/sgf/bsgf/article-abstract/176/3/243/88426/A-giant-brachyopoid-temnospondyl-from-the-Upper?redirectedFrom=fulltext
* https://www.tandfonline.com/doi/abs/10.1671/0272-4634%282000%29020%5B0462%3AAPOTBT%5D2.0.CO%3B2