1. Angel sharks caught off the Wales coast in the 60s and 70s
Sightings from fishing boats suggest the mysterious angel shark is present in Welsh waters, although no-one knows exactly where.
The shark's only established stronghold is the Canary Islands, where the animals have been filmed on the seabed.
Wales could be a key habitat for the critically endangered shark, which is from an ancient and unique family.
"If we lose the angel shark, we lose a really important lineage of evolutionary history that we can't get from any other shark species," Joanna Barker, of the Zoological Society of London (ZSL), told BBC News.
3. The angel shark (Squatina squatina) has a flat body and grey skin. It can grow up to 1.8 m in length and 80 kg in weight.
Facts on the angel shark
- "Flat sharks" that spend much of the time camouflaged on the bottom of the seabed, where they lie in wait for fish
- Once common across the east Atlantic and Mediterranean seas, historic records suggest the Welsh coast may be an important habitat
- Angel sharks have declined across their range because of a number of threats, including habitat disturbance, pollution and accidental fishing catch
Ms Barker, who is a marine biologist, studied the shark off the Canary Islands.
On her return, she stumbled upon a book in the ZSL library, describing the presence of the angel shark in Wales 100 years ago.
She was determined to find out more about the shark and started a project with colleagues at Cyfoeth Naturiol Cymru - Natural Resources Wales.
5. Photo taken off Aberdovey in the 70s-80s
After appealing for information from fishers and the local community, intriguing photographs came to light.
The shark was clearly a prize catch in the 1970s and 1980s, before it became a protected species.
Sightings were made recently off Cardigan Bay, in the Bristol Channel and to the north of Holyhead, she said.
"What we really want to try and understand is what sort of numbers are we talking about and where are their important habitats, because there could be some really critical areas for angel sharks in Wales," she added.
7. The shark lurks on the ocean floor
A big question is whether the angel sharks are moving back and forth between Wales, the Canary Islands, or elsewhere, and whether they are distinct populations.
Genetic research using swabs taken from a shark's skin could give the answer, say scientists.
Dives are planned for later in the year, to look for direct evidence of angel sharks. Meanwhile, roadshows have been set up to gather more pictures and memories.
9. Pwllheli beach, Wales: possible haven to the angel shark?
The angel shark was recently assessed along with other sharks, rays and chimeras (fish with cartilage in place of bones) for the Edge of Existence - Evolutionarily Distinct & Globally Endangeredprogramme.
Regarded as a particularly precious shark species, it is at the end of a distinct branch of the tree of life.
The roadshow will be travelling across Wales, starting in Nefyn on 25 January. All events will be running from 10:00 to 17:00 GMT.
- Friday 25 - Saturday 26 January - Llŷn Maritime Museum, Nefyn
- Monday 11 - Tuesday 12 February - Milford Heritage Museum, Milford Haven
- Friday 15 - Saturday 16 Feb - National Waterfront Museum, Swansea
- Friday 1 - Saturday 2 March - The National Library of Wales, Aberystwyth
- Monday 4 - Tuesday 5 March - Holyhead Sea Cadets, Holyhead.