SYDNEY: Australia’s burrowing echidna advanced from a water-dwelling ancestor in an “extraordinarily uncommon” organic occasion, scientists stated on Tuesday (Apr 29) in a brand new research of the peculiar egg-laying mammals.
With highly effective digging claws, protecting spikes and extremely delicate beaks, echidnas are nicely suited to a life shuffling by the forest undergrowth.
However a group of Australian and worldwide scientists imagine most of the echidna’s uncommon traits had been first developed tens of millions of years in the past when its ancestors splashed by the water.
“We’re speaking a few semiaquatic mammal that gave up the water for a terrestrial existence,” stated palaeontologist Suzanne Hand, from the College of New South Wales.
“Whereas that may be a particularly uncommon occasion, we expect that is what occurred with echidnas.”
Echidnas and one other Australian oddity, the semi-aquatic platypus, are believed to have advanced from a typical ancestor known as Kryoryctes cadburyi that lived in Australia greater than 100 million years in the past.
Researchers studied the one identified bone fragment left by this ancestor, which was found amongst a trove of fossils at Dinosaur Cove in southern Australia some 30 years in the past.
Platypus bones had been just like this historic ancestor, Hand stated, with a thick and heavy construction that supplied ballast for diving.
Echidnas, compared, had very skinny bone partitions that made it simpler to stroll on land, Hand stated.
This indicated echidnas had been descended from a water-dwelling ancestor however had advanced to reside on land, the analysis discovered.
It was much more frequent for prehistoric mammals to go from land to water, Hand stated, pointing in direction of seals, whales, dolphins and dugongs.
The researchers stated these findings gave the impression to be supported by different echidna traits.
Echidnas have backward-facing hind ft that assist them shift mounds of soil when burrowing.
These ft might have first developed as rudders serving to the echidna’s ancestor navigate fast-moving waterways, Hand stated.
Echidnas even have a “diving reflex” when submerged in water, which tells their physique to preserve oxygen serving to them maintain their breath for longer.
Echidnas and platypus are monotremes, a uncommon group of mammals that lay eggs as a substitute of reside younger.
“We’re hoping we’ll uncover different ancestral monotremes that can assist unravel the early historical past of this most fascinating group of mammals,” stated research co-author Michael Archer.
The analysis was printed in peer-reviewed journal PNAS.
