Ancient fossil shows what you get crossing a platypus and echidna

A prehistoric species dubbed an “echidnapus” has been unearthed in rare opal fossils in New South Wales.

The 100-million-year-old fossils ”foreshadow” the modern platypus and echidna – the only monotremes (egg-laying mammals) in the world today, according to Australian Museum Research Institute director and chief scientist, Professor Kris Helgen.

“Opalios splendens sits on a place in the evolutionary tree prior to the evolution of the common ancestor of the monotremes we have today,” Helgen said.

“Its overall anatomy is probably quite like the platypus, but with features of the jaw and snout a bit more like an echidna – you might call it an ‘echidnapus’.

“The story of how our egg-laying mammals evolved is ‘toothy to toothless’ on the oldest monotreme, teinolophos trusleri, which dates back to Victoria 130 million years ago.

“What we see at Lightning Ridge is that by 100 million years ago, some of the monotremes still have five molars but some of them are down to three.”

The echidnapus – opalios splendens – is one of three previously-unknown prehistoric monotreme species discovered in the Lightning Ridge region.

The fossils were found by Elizabeth Smith and her daughter Clytie of the Australian Opal Centre in Lightning Ridge, who have spent decades working and searching over the opal fields.

“Opal fossils are rare, but opalised monotreme fossils are infinitely more rare, as there’s one monotreme fragment to a million other pieces,” Elizabeth Smith said.

“We don’t know when, or exactly where, they’ll turn up.”