About 100 million years ago, in what is now Australia’s opal field, a strange, furry, egg-laying, rabbit-sized mammal glided through a puddle along a massive polar floodplain.
This mammal – Opalius is magnificent But this creature, which scientists thankfully nicknamed “echidnapus,” was among the ancient descendants of the monotremes, one of the planet’s most unique animal species.
New scientific research published on Monday showed that echidnas have characteristics of the last two remaining members of their tribe.
Modern Australia is a bastion of the one-hole species; the extremely peculiar platypus, a nippleless Australian mammal with a duck-like beak, and the spiny echidna with its hyperextended snout, also living in New Guinea.
But the discovery of echidnapus and two other ancient monotremes in opal field fossils means that at least six species of monotremes now exist in the northernmost outback of New South Wales.
“It’s like discovering a completely new civilization,” said Prof Tim Flannery, lead author of the new study published in the palaeontology journal Alcheringa.
“Today, Australia is known as the land of marsupials, but the discovery of these new fossils is the first indication that Australia was previously home to a diversity of monotreme species.
Relating to: ‘Unlike anything alive today’: Gippsland fossil reveals secrets of kangaroos that went extinct 46,000 years ago
“There are no other mammal species in the area where the fossils were found. “This suggests that Australia experienced a single-hole era when they were the dominant mammal.”
The discovery of opalized jawbones in an area known as Lightning Ridge almost never occurred. Elizabeth Smith and her daughter Clytie, of the Australian Opal Centre, found the specimens while sifting through the tailings pile of an opal mine about 25 years ago.
“It was largely by luck that I found the pieces,” he said. “But I quickly realized it was a mammal and therefore really important.”
He donated the specimens to the Australian Museum at the turn of the millennium. These days, his findings and those sent to him by opal miners remain at the nonprofit opal center.
“These examples are a revelation,” he said. “It’s extremely exciting. “They are showing the world that long before Australia became a land of marsupials and marsupials, it was a land of furry egg-layers (monotremes).”
The three species are described in the journal from opacified jaws dating back to the Cretaceous epoch, between 102 and 96.6 million years ago.
Second new ancient monotreme, Parvopalus clytieiwas a small land mammal. a third, Dharragarra auroraFlannery said it looked “remarkably like a modern platypus.”
Prof Kris Helgen, Director of the Australian Museum Research Institute, said: Opalios splendens It had characteristics of the earliest known monotremes, but other features suggestive of modern echidnas and platypuses.
Relating to: One-hole dreams: Plan to reintroduce platypuses to Adelaide’s once ‘harmful’ river
He said: “Its general anatomy is probably similar to a platypus, but the jaw and nose features are a little more echidna-like; you could call it an ‘echidnapus’.”
Flannery said Echidnapus cannot be its immediate ancestor because it is so old. However, it had a narrow beak like an echidna and five molars like a modern platypus.
One of the intriguing points about the modern platypus, an animal so strange that the 18th-century British scientist George Shaw thought it was a potential hoax, is how it loses its teeth (the young ones lose their molars when they become adults).
“This is a mystery we think we may have solved,” Flannery said. About two million years ago the Australian water mouse, known as the rakali, arrived in Australia.
This likely caused platypuses to seek out “softer, slipperier foods that were best handled with the leathery pads adults use today,” Flannery said.
All six of Lightning Ridge’s monotremes “potentially have evolutionary fates” that could split in all directions, he said, but are “very distant ancestors and relatives of current living monotremes.”
But between 100 and 54 million years ago, the single-hole variety disappeared. “Was it a result of the asteroid that killed the dinosaurs? Did they compete with marsupials? “We don’t know, but there has been a change.”
Australian Museum palaeontology curator Dr. Matthew McCurry said: “We have very few single-hole fossils and so finding new fossils can tell us more about where they lived, what they looked like and how changes in the environment affected their evolution.
“Every significant single-hole fossil known to date, from Teinolophos, a tiny mouse-like creature found in Antarctica 130 million years ago, fits this evolutionary story.”