(Reuters) - Scientists in Australia have unearthed beautifully preserved fossilized hearts and other internal organs of ancient armored fish in a discovery that provides insight into the evolution of ...

In biology, one long-running debate has teeth: whether ancient fish scales moved into the mouth with the origin of jaws, or if the tooth had its own evolutionary inception. Recent studies on species ...

Many animals including humans reproduce through sexual intercourse and researchers have found evidence that this process is pioneered by a fish that existed in Scotland nearly 400 million years ago.

(CNN) — Hundreds of millions of years ago, jawless fishes swam Earth’s seas, their brains protected on the outside by armored skin, and on the inside by plates made of cartilage. Scientists are still ...

The fossilized skull of Coccocephalus wildi, an early ray-finned fish that swam in an estuary 319 million years ago.Jeremy Marble/University of Michigan News Scientists discovered the fossilized brain ...

Derpy from the side and hellish from below, the lamprey is the bane of the Great Lakes fisheries industry. A jawless, bloodsucking fish, the lamprey is often considered an ancestral early vertebrate ...

A mass extinction of fish 360 million years ago hit the reset button on Earth’s life, setting the stage for modern vertebrate biodiversity. The mass extinction scrambled the species pool near the time ...

Scientists have unearthed a fossilized fish that was once the biggest vertebrate of its day. The predatory sea creature, dubbed Megamastax amblyodus, which means "big mouth, blunt teeth," prowled the ...

WASHINGTON (Reuters) - Let's face it. It's easy to take for granted that mammals, birds, reptiles, amphibians and fish - vertebrates just like people - have a face. But it has not always been the case ...