In the case of what came first, the thorny devil or the desert, scientists believe the former is the answer.
But this only brings more questions about the unique Australian lizard.
For instance, how can an animal that has evolved to be a desert specialist — it stays hydrated by its skin drawing up moisture from the ground — pre-date its environment?
Evolutionary biologist Ian Brennan is based at London's Natural History Museum.
Tens of millions of years ago, the thorny devil broke off from its closest relative, the tree-dwelling chameleon dragon of Australia's Top End, Dr Brennan said.
The thorny devil is somewhere between 10 and 20 million years old, he says.
"They're older than the Australian deserts, which may have ebbed and flowed in size over the past 20 million years or so," Dr Brennan said.
"[They] have only really come into the habitat that we think of as Australian deserts within the past million or two years."
Dr Brennan believes genetics might be able to provide some insights into the origin of the thorny devil.
"If they followed the expansions of desert, we can find signatures of that in the genetic information," he said.
Formerly based at the Australian National University, Dr Brennan is drawing on genetic data in specimens from across the thorny devil's range, which includes much of inland Western Australia, the Northern Territory and South Australia.
Some devils have more bones than others
To better understand where the lizard originated from before it spread across the country, Dr Brennan plans to investigate what seems like a split in the species to the north and south of the Murchison River.
He says there's a genetic sample "blackhole" between Perth and Shark Bay, 800 kilometres north in WA's Mid-West.
"Devils above and below the river have different set-ups of bones in their fingers and toes," he said.
"We want to see if this lines up with genetic splits in the populations of the species.
"Genetics can help us answer this question and identify what we call cryptic species."
It is believed that the thorny devil has more recently evolved to have less finger and toe bones.
But some thorny devils in WA still have more bones than their eastern relatives.
"We have no idea if it's a functional thing, or just kind of a whim of evolution," Dr Brennan said.
"Maybe it has something to do with their lifestyle, maybe it's a freak mutation that wasn't negative. We don't really know.
"Thorny devils are just an amazing, amazing animal. They don't look like any other reptile on Earth — they kind of look like aliens."
Dead devils could help tell the tale
To help fill the knowledge gap in the lizard's evolution, Dr Brennan needs about 20 thorny devil specimens and is calling on citizen scientists to help.
On their travels, if people come across a thorny devil killed in a vehicle strike between Perth and Shark Bay, Dr Brennan has asked for the lizard to be collected.
He says because of their thick armour, thorny devils remain remarkably intact after being killed by a vehicle.
Dr Brennan has asked travellers to collect only deceased specimens, put them in a container or ziplock bag, and store them in an esky or fridge.
Specimens can then be dropped off at the WA Museum in Perth or Geraldton.
The research is part of the taxonomy and conservation genomics project under the Australian Amphibian and Reptile Genomics Initiative.
