Bizarre ‘platypus fish’ found on Australia’s original reef

Scientists in Australia have discovered a remarkable ancient fish fossil with a long snout, reminiscent of a platypus bill.

The fossil, named Brindabellaspis after the nearby Brindabella Ranges, belong to an extinct group called the placoderms and was first found in 1980 in limestone around Lake Burrinjuck in NSW, an area containing some of the the world’s earliest known reef fish fauna from about 400 million years ago.

Now palaeontologies from Flinders University and the Australian National University have reconstructed two of the ancient fossils and discovered the fish had a long bill extending out in front of its eyes.

“This was one strange looking fish,” says study author Benedict King, a Flinders University graduate now based Naturalis Biodiversity Centre in Leiden, Netherlands.

“The eyes were on top of the head, and the nostrils came out of the eye sockets. There was this long snout at the front, and the jaws were positioned very far forward,” he says.

The fossil had another surprise: a unique sensory system on the snout which turned out to be a modified form of the pressure sensor system found in other fish.

The paper, ‘New information on Brindabellaspis stensioi Young, 1980, highlights morphological disparity in Early Devonian placoderms’ (2018), by Benedict King, Gavin C Young and John A Long, has been published in Royal Society Open Science.

“We suspect that this animal was a bottom-dweller,” says Professor John Long. “We imagine it used the bill to search for prey, somewhat like a platypus, while the eyes on top of the head looked out for danger from above.”

Dr Gavin Young, who has spent more than 50 years researching fossil fish from Lake Burrinjuck, found the first two specimens but the sensitive snout region was missing.

“This is a fossil site that just keeps giving,” says Dr Young from the ANU Research School of Physics and Engineering.

Limestone outcrops on the shores of Lake Burrinjuck preserve an ancient reef fish fauna from an estimated 400 million years ago.

“There are over 70 species of fish known from this ancient coral reef ecosystem, and this finding shows they came in all shapes and sizes. Clearly this ancient reef was a thriving hotspot for evolution, as are the coral reefs of more recent times”.

“When we saw the dense sensory tubes on another broken snout, we immediately thought of the local platypus,”  he says. “I am very gratified there is finally an accurate reconstruction of this strange skull.

Of more than 70 species of fish known from this ancient coral reef ecosystem, Brindabellaspis is certainly the weirdest and most specialised example. “Clearly this ancient reef was a thriving hotspot for evolution, as are the coral reefs of today,” Dr Young says.

The fossil re-examination filled in the gaps, “but not in a way anyone expected,” says Flinders University Professor John Long.

“Despite this being one of the earliest well-known ecosystems including many species of fish, the inhabitants of this ancient reef were clearly not in any way primitive,” Professor Long says.

“The new findings show that they were highly adapted and specialised in their own right.”

A string of recent discoveries from the Lake Burrinjuck fossil site have included evidence for electroreception, new information on the evolution of jaws and a tiny skull that bridges the gap between the two major divisions of the bony fish.

Naturalis Biodiversity Centre in Leiden Dr Martin Rücklin, who supervises Benedict King in Holland, says the Lake Burrinjuck area keeps producing exciting discoveries.

“Brindabellaspis is one of the most important placoderms due to its excellent preservation, so this new information on its anatomy is crucial deciphering the phylogenetic relationships of early jawed vertebrates,” he says.

Read ‘Fossil fish with platypus-like snout shows that coral reefs have long been evolution hotspots’ by Flinders Universityvertebrate palaeontologist PhD candidate Benedict King’s summary in The Conversation here

Flinders University is launching the first and only palaeontology named degree in Australasia at the purpose-built Flinders Palaeontology Laboratory in 2019. Find out more here 

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