A new genus and species of large-sized tomistomine crocodylian has been identified from a large, incomplete skull found more than a century ago in Queensland, Australia.
Artistic representation of Gunggamarandu maunala. Image credit: Eleanor Pease.
Gunggamarandu maunala lived somewhere between 2 and 5 million years ago (Pliocene or Pleistocene epoch) in what is now south-eastern Queensland, Australia.
It belongs to Tomistominae, a subfamily of crocodylians that includes one living species, the false gharial (Tomistoma schlegelii).
“The false gharial is restricted to the Malay Peninsula and parts of Indonesia,” said Jorgo Ristevski, a Ph.D. candidate in the School of Biological Sciences at the University of Queensland.
Gunggamarandu maunala is one of the largest crocodylians to have ever inhabited Australia.
“At the moment it’s difficult to estimate the exact overall size of Gunggamarandu maunala since all we have is the back of the skull — but it was big,” Ristevski said.
“We estimate the skull would have been at least 80 cm (2.6 feet) long, and based on comparisons with living crocs, this indicates a total body length of around 7 m (23 feet).”
“This suggests Gunggamarandu maunala was on par with the largest Indo-Pacific croc — the saltwater crocodile (Crocodylus porosus) — recorded.”
Gunggamarandu maunala, holotype: (a) photograph, and (b) annotated digital model of the cranium in dorsal views; (c) photograph, and (d) annotated digital model of the cranium in occipital views; (e) hypothetical outline of the skull of Gunggamarandu maunala in dorsal view, with the specimen depicted in its corresponding position. Image credit: Ristevski et al., doi: 10.1038/s41598-021-91717-y.
A partial skull of Gunggamarandu maunala was unearthed in the Darling Downs region in the 19th century.
It possesses a unique combination of features that distinguishes it from other crocodylians.
“We had the skull CT-scanned, and from that we were able to digitally reconstruct the brain cavity, which helped us unravel additional details about its anatomy,” Ristevski said.
“With the exception of Antarctica, Australia was the only other continent without fossil evidence of tomistomines,” he added.
“But with the discovery of Gunggamarandu maunala we can add Australia to the ‘once inhabited by tomistomines’ list.”
The findings were published in the journal Scientific Reports.
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J. Ristevski et al. 2021. First record of a tomistomine crocodylian from Australia. Sci Rep 11, 12158; doi: 10.1038/s41598-021-91717-y
