"Long before it's in the papers"
September 13, 2011

RETURN TO THE WORLD SCIENCE HOME PAGE

In “vicious” ancient river waters, a sharp-toothed giant fit right in

Sept. 13, 2011
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.

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)

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 five or six feet (150-180 cm) 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 Pa­le­on­tol­ogy.

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 )

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 hon­or 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.

* * *

Send us a comment on this story, or send it to a friend

 

A newfound fossil reveals the existence of a huge fish that once prowled the bottom of North American waterways, waiting for prey to get too close to 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 5 or 6 feet (150-180 cm) 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 Paleontology. The 375-million-year-old beast’s discoverers were 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 the remote Nunavut Territory of Arctic Canada. 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 honor 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 the 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.