(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 ...

A tiny desert fish survives in a sun-scorched cavern on the edge of extinction. Here’s how it’s offering scientists a rare ...

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 ...

A skull of Romundina, one of the earliest jawed fish, is shown in this image courtesy of Uppsala University in Sweden. REUTERS/Philippe Loubry, MNHN-CNRS-UPMC/Handout (Reuters) By Will Dunham ...

A stunningly preserved, soft-bodied fish that is more than 500 million years old could be the ancestor of almost all living vertebrates. The fossilized fish, called Metaspriggina, sports ...

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.

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 ...

At the bottom of the world’s trenches, there’s a fish that shouldn’t exist. Here’s how it earned the title of the ...

Latest findings support the theory that teeth in the animal kingdom evolved from the jagged scales of ancient fish, the remnants of which can be seen today embedded in the skin of sharks and skate. In ...