For 33 years, Peter A. Rona has pursued an ancient, elusive animal, repeatedly plunging down more than two miles to the muddy seabed of the North Atlantic to search out, and if possible, pry loose his quarry.

Like Ahab, he has failed time and again. Despite access to the world’s best equipment for deep exploration, he has always come back empty-handed, the creature eluding his grip.

The animal is no white whale. And Dr. Rona is no unhinged Captain Ahab, but rather a distinguished oceanographer at Rutgers University. And he has now succeeded in making an intellectual splash with a new research report, written with a team of a dozen colleagues.

They have gathered enough evidence to prove that his scientific prey  an organism a bit larger than a poker chip  represents one of the world’s oldest living fossils, perhaps the oldest. The ancestors of the creature, Paleodictyon nodosum, go back to the dawn of complex life. And the creature itself, known from fossils, was once thought to have gone extinct some 50 million years ago.