A skink as big as a human arm has been comically dubbed the Mega Chonk after its bones were found alongside other blasts from the prehistoric past. After years of careful work, researchers from Flinders University have formally described what is by far the largest skink discovered so far. Its official name is Tiliqua frangens, or Frangens for short. But its bulky bod and serious spiky armour mean it already has a range of colourful nicknames including Mega Chonk and Chonkasaurus. Dr Kailah Thorn, a palaeontologist, said she hoped people would have some fun with the discovery. “There’s a bit of a meme trend around large ‘chonky’ animals with phrases like ‘oh lawd, he/she comin’ ’ associated with their arrival,” she said. “I’m keen to see what kind of memes come out when this animal is released on the world.” Thorn, who studied fossils of the Frangens when she was completing her PhD, says it was truly impressive in terms of size – about a thousand times larger than most skinks. It would have been similar in appearance to its closest living relative – the blue-tongued shingleback, or sleepy lizard – and existed about 50,000 years ago alongside other extinct megafauna including the marsupial lion and the diprotodon. Diana Fusco, from the university’s palaeontology lab, said the mega skink’s existence had been carefully pieced together from bones unearthed at Wellington Caves in New South Wales and fossils held in museums around Australia. “In the dig at Wellington Caves, we started finding these spiked armoured plates that had surprisingly never been recorded before,” she said. “We knew we had something interesting and unique.” Thorn said caves could be treasure troves when it came to getting a handle on prehistoric biodiversity. That’s certainly been true of Cathedral Cave in the Wellington system, where Frangens bones continue to be found. “There used to be a natural hole in the ceiling ... so there’s marsupial lions and thylacines and stuff in there as well, that have fallen in, or wandered in, and not been able to get out again,” Thorn said. “It’s a great way to sample biodiversity in a snapshot of time.” A paper about the Frangens has been published in the Royal Society’s flagship biological research journal.