In ‘vicious’ ancient river waters, a sharp-toothed giant fit right in tagged: , , , , , , ,

In ‘vicious’ ancient river waters, a sharp-toothed giant fit right in

Posted by in Life, Palaeontology

Courtesy of the Academy of Natural Sciences and World Science staff

A newfound fossil reveals the existence of a huge fish that once prowled the bottom of North American waterways, waiting for prey to wander near its fearsome mouth, scientists say.

‘I wouldn’t want to be wading or swimming in waters where this animal lurked,’ said Edward ‘Ted’ Daeschler of the Philadelphia-based Academy of Natural Sciences, co-author of a paper describing the find. ‘Clearly these Late Devonian ecosystems were vicious places,’ he added, referring to the Devonian geological period that ran from about 415 to 360 million years ago, before backboned animals crawled on land.

The fish, dubbed Laccognathus embryi, was ‘a large, bottom-dwelling, sit-and-wait predator with a powerful bite,’ Daeschler added. The creature probably grew to about 1.5-1.8m long and had a wide head with small eyes, according to the researcher and his colleagues. Daeschler and Jason Downs of the Academy and colleagues from the University of Chicago and Harvard University describe the find in the current issue of the Journal of Vertebrate Palaeontology.

The 375-million-year-old beast’s discoverers are the same group that previously found Tiktaalik roseae, called ‘a missing link’ between fish and the earliest limbed animals. The fossil remains of the new species were found at the same site as Tiktaalik, on Ellesmere Island in Arctic Canada’s remote Nunavut Territory.

The Devonian is often called the Age of Fishes because of the rich variety of aquatic forms that populated the seas, lagoons and streams. Laccognathus was a type of fish known as a lobe-finned fish whose closest living relative is the lungfish. The researchers named the new species in honour of Ashton Embry, a Canadian geologist whose work in the Arctic islands paved the way for the authors’ explorations.

Laccognathus, which means pitted jaw, is an evolutionary group of fishes previously known only from Eastern Europe. The new fossil represents a new species within that group or genus, and extends its geographic range to North America, Daeschler and colleagues said. This confirms a direct connection of the North American and European landmasses during the Devonian, they added.

Caption thumbnail: A photograph and line drawing of the skull of Laccognathus embryi, a new species of predatory fish from the Devonian Period. Note the wide head, large mouth and small area for the eyes. (Photo: Ted Daeschler/ANSP, drawing: K. Monoyios)

Caption: An artist’s rendering of Laccognathus embryi in its habitat during the Devonian Period. The fossils were discovered in the Canadian Arctic, but the conditions when the animal lived are believed to have been subtropical. (Credit: Jason Poole/ANSP)

Source: World Science, http://www.world-science.net