Canadian fossil fish discovery

From World Science:

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.

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.

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.

See also here.

Fossil shark: here.

The remains of several new toothy shark species, with at least three dating to 270 million years ago, have been unearthed in Arizona, according to a new study: here.