Brindabellaspis had nostrils in its eye sockets and a long bill with jaws

This article is more than 2 years old

This article is more than 2 years old

Palaeontologists have reconstructed an ancient Australian fish that swam on the sea floor like a stingray and had the long bill of a platypus.

Fossils that date back 400m years have allowed scientists to piece together a revealing picture of the strange fish, which had nostrils coming from its eye sockets and a long bill or snout with jaws.

It is named Brindabellaspis after the Brindabella range, near Canberra, and belongs to an extinct group of armoured prehistoric fish known as placoderms.

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Scientists from the Australian National University and Flinders University have dated the fossils to the early Devonian period, more than 175m years before the first dinosaurs.

They were discovered in limestone around the Lake Burrinjuck dam at the head of the Murrumbidgee river, north of the Brindabellas in New South Wales.

The area contains some of the earliest reef fish fauna and the world’s finest example of an ancient tropical coral reef.

It was a thriving biodiversity hotspot that would rival today’s Great Barrier Reef.

Dr Gavin Young, the ANU palaeobiologist who discovered the first fossils in 1969, said Brindabellaspis is the strangest of the more than 70 species of fish found in the ancient ecosystem.

“This thing is really weird,” he said. “It doesn’t really fit in anywhere.”

It is believed the fish was a bottom dweller, which used its snout or bill to search for prey.

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

“It has a very weird and unexpected skull shape with a long snout and the possible capacity to use electrical reception to find animals in the soft mud at the sea bottom,” he said.

Benedict King, the lead author on the paper along with Young and fellow Flinders researcher John Long, wrote in the Conversation that the Burrinjuck fauna highlighted a major difference between reef ecosystems at different points in time.

“Although coral reefs have always been diversity hotspots, the groups of animals making up the ecosystems have changed drastically,” King says. “Brindabellaspis, for example, is a placoderm, a group of jawed vertebrate, often known as the ‘armoured fish’. Placoderms were the dominant fish group in the Burrinjuck reefs, followed by lungfishes.

“Another reef from a similar time period, the Gogo reef in the Kimberley region of Western Australia, is also dominated by placoderms and lungfishes. Today the placoderms are completely extinct, while the lungfishes are reduced to just six living species worldwide ... all of which live in fresh water.

“Modern reefs, on the other hand, are dominated by teleost fish, a group that first appeared around 230 million years ago, long after the Burrinjuck reef.”

The paper is published in the journal Royal Society Open Science on Wednesday.