An amateur fossil hunter discovered a new species of fish after frosty weather cracked open a slab of rock to reveal 330 million-year-old remains.
The fossil may be an ancestor of the sturgeon
Patrick Gavin, 34, found the fossilised fish, with its teeth, scales, and even its stomach contents still visible, at a site near his home in Dunbartonshire.
Experts confirmed it is an unknown species "totally new to science".
And it may even be named Gavin after its finder, who has since donated the relic to Glasgow's Hunterian Museum.
Mr Gavin, an upholsterer, said: "I've been interested in fossils for about two years now and I've got to know the different types of fish.
"I knew straight away this one was different. It feels brilliant to have found something like this."
The father-of-one took his find to the Hunterian Museum, where staff decided to invite leading palaeontologist Professor Mike Coates from the University of Chicago to identify it.
The 15-centimetre fossil is believed to be the remains of a previously undiscovered fish, possibly an ancestor of the sturgeon.
Its small scales, pointed teeth and the position of the fins distinguish it from any known species.
It is thought to have lived about 330 million years ago.
Dr Neil Clark, curator of the museum's geology section, said: "It is always a dream of palaeontologists to find something totally new to science like this.
"It's a coup for Patrick Gavin and it is also a coup for the museum."
The fossil, discovered a few months ago, is still under examination and has yet to be named.
Dr Clark said new species are usually named after the location where they are found, after a prominent feature of the creature, or after its discoverer.
Mr Gavin, who has found several other extremely rare species over the years, said he will continue hunting at his local site.