Meet the ‘River Boss’: Huge prehistoric crocodile the length of a London BUS roamed south-east Queensland’s waterways up to five million years ago

  • Giant prehistoric crocodile nicknamed the ‘River Boss’ identified by scientists
  • Researchers say it grew to 23ft long and may be largest to have lived in Australia
  • Species identified by digitally reconstructing a partial skull found in about 1875
  • Scientists think it roamed Queensland’s waterways up to five million years ago 

Nicknamed the ‘River Boss’ and almost as big as a London bus, the discovery of an enormous prehistoric crocodile sounds more like the premise of a low-budget horror film.

But the beast did in fact roam south-east Queensland’s waterways up to five million years ago, researchers say, and may be the largest to have lived in Australia.

They identified Gunggamarandu maunala – whose name means ‘River Boss’ – after analysing a partial skull unearthed in about 1875.

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Enormous: Researchers have identified a prehistoric crocodile, named the ‘River Boss’, which they believe may be the largest to have lived in Australia. It is pictured in an artist’s impression

Size: The crocodile was estimated to have been about 23ft (7m) long, while its skull alone is thought to have been at least 31 inches (80cm) in length (pictured as a comparison to a human)

WHAT DO WE KNOW ABOUT THE EVOLUTION OF CROCODILES? 

Of all the reptiles alive today, crocodiles may be the least changed from their prehistoric forebears of the late Cretaceous period, more than 65 million years ago.

However, the even earlier crocodiles of the Triassic and Jurassic periods sported some distinctly un-crocodile-like features, such as bipedal postures and vegetarian diets.

Along with pterosaurs – the family of flying reptiles – and their land-based relatives the dinosaurs, crocodiles were an offshoot of the archosaurs, the ‘ruling lizards’ of the early to middle Triassic period.

The earliest dinosaurs and the earliest crocodiles resembled one another a lot more than either resembled the first pterosaurs, which also evolved from archosaurs. 

What distinguished the first crocodiles from the first dinosaurs was the shape and musculature of their jaws, which tended to be much more deadly, as well as their relatively splayed limbs – as opposed to the straight, ‘locked in’ legs of theropod dinosaurs. 

It was only well into the Mesozoic Era that crocodiles evolved the three main traits with which they’re associated today: stubby legs; sleek, armoured bodies; and marine lifestyles.

‘It’s difficult to estimate the exact overall size of Gunggamarandu since all we have is the back of the skull – but it was big,’ said Jorgo Ristevski, a PhD candidate from the University of Queensland’s School of Biological Sciences.

‘This is one of the largest crocs to have ever inhabited Australia.’

He said the crocodile was estimated to have been about 23ft (7m) long, while its skull alone is thought to have been at least 31 inches (80cm) in length.  

‘This suggests Gunggamarandu was on par with the largest Indo-Pacific crocs ever recorded,’ Ristevski added.

‘The exact age of the fossil is uncertain, but it’s probably between two and five million years old.’ 

Researchers digitally reconstructed the crocodile’s skull using CT scans, helping them to learn more about the anatomy of its brain cavity. 

Gunggamarandu belonged to a group of crocodylians called tomistomines or ‘false gharials’.

‘Today, there’s only one living species of tomistomine, Tomistoma schlegelii, which is restricted to the Malay Peninsula and parts of Indonesia,’ Mr Ristevski said.

‘With the exception of Antarctica, Australia was the only other continent without fossil evidence of tomistomines.

‘But with the discovery of Gunggamarandu we can add Australia to the “once inhabited by tomistomines” list.’

The name of the new species honours the First Nations peoples of the Darling Downs area where the fossil was discovered, incorporating words from the languages of the Barunggam and Waka Waka nations. 

Gunggamarandu means ‘river boss’ and maunala ‘hole head’, in reference to the openings on the top of the crocodile’s skull.

Last December scientists identified another prehistoric crocodile which measured more than 16ft long.

Where did it roam? The name of the new species honours the First Nations peoples of the Darling Downs area (pictured with a star above), where the fossil was discovered in about 1875

Fossilised skull: Gunggamarandu means ‘river boss’ and maunala ‘hole head’, in reference to the openings on the top of the crocodile’s skull (pictured)

Analysing: Researchers digitally reconstructed the crocodile’s skull using CT scans (pictured), helping them to learn more about the anatomy of its brain cavity

Fossils of Paludirex vincenti, nicknamed the ‘swamp king’, were first unearthed in the 1980s but the creature was only recently identified as a distinct species.

It was an apex predator that preyed on giant prehistoric kangaroos in south Queensland millions of years ago.

In May, the skull of an 8 million-year-old crocodile that used to hunt ‘big prey’ was also found in Australia, with researchers believing it to be part of a new species. 

It was approximately the same size as a modern-day saltwater crocodile, or roughly 17ft in length and approximately 1,000lbs. 

The latest research has been published in the journal Nature Scientific Reports.

WHAT WAS THE TIMELINE OF CROCODILE EVOLUTION?

250,000,000 BC – Xilousuchus

Three feet long. 5-10lbs. Lived in the swamps of eastern Asia. Ate small animals. Ridge of fan-like ‘sails’ on their back. Split off into pre-historic crocodiles and early dinosaurs. 

228,000,000 BC – Phytosaur

Alive during the early Jurassic period. Most related to crocodilians. Herbivores. Looked much like modern day crocodiles – except their nostrils were located on the top of their head rather than the tops of their snout.

200,000,000 BC – Erpetosuchus

Bipedal. Didn’t resemble modern crocodiles in behaviour or body shape except the shape of their head. 

110,000,000 BC – Sarcosuchus 

Middle Cretaceous period. 40ft long. 10-15 tons. Ate dinosaurs and fish. Lived in the rivers of Africa. Odd protrusion on it’s snout. Looked and behaved like it’s modern decedents, but it was twice as long and about 10 times as heavy. 

100,000 BC – Stomatosuchus 

36 ft. long. ten tons. Ate plankton and krill with its high pelican-like jaw. 

80,000,000 BC – Beinosuchus

Greek for terrible crocodile. Lived in the rivers of North America. About 33 ft long and 10 tons. They had a 6ft. long skull. Fed on fish, shell fish, and land creatures. Evidence in fossils suggests that they attacked large North American tyrannosaurs.

70,000,000 BC – Champsosaurus  

Five ft long, 25-50 pounds, ate fish, and lived in the rivers of North America and western Europe. Long narrow profile and a tooth studded snout. Survived the Cretaceous-Paleogene extinction event that killed off three-quarters of the plant and animal species on Earth – including the dinosaurs.

65,000,000 BC – Cretaceous-Paleogene Extinction Event

Non-avian dinosaurs were wiped out and more than half the world’s species were obliterated. This mass extinction paved the way for the rise of mammals and the appearance of humans. 

55,000,000 BC – Crocodylidae (Modern day crocodile)

The modern day crocodile – including the saltwater, Nile, and American variants – spread throughout the world. Though it looks prehistoric, it is a highly evolved and complex organism that is a successful predator.

23,000,00 BC – Quinkana

Nine feet long, 500 pounds. Consumed red meat in woodlands. Long curved teeth and long legs, unlike modern croc’s short legs. These crocodiles continuously get smaller because of environmental changes.

4,200,000 BC – Crocodylus thorbjarnarsoni

This is a very close relative of the modern day crocodile. Large skull and small raised rim in front of the eyes. Likely prayed on early humans. Lived in the Turkana basin in Kenya. Could be the largest known true crocodile.

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