© National Museum HistoryElvis the Thornback skate, with an extra fin resembling a quiff, will live in an open top tank in the Blue Reef Aquarium in Portsmouth.
An unusual skate has been caught by fishermen in the Solent with an extra fin.
It was taken to the Portsmouth Blue Reef Aquarium for identification, where it is now being held for safekeeping.
Aquarium staff have nicknamed it Elvis because the fin resembles a quiff.
Skate or shark?
Aquarium staff originally thought the extra appendage was a dorsal fin from a genetic throwback to a shark. Skate are distantly related to sharks.
On closer inspection, however, they realised it was more likely a bizarre mutation.
Natural History Museum fish curator James Maclaine, who was brought in to identify the fin, realised it was something entirely new.
'Mutated skates do turn up from time to time, sometimes with fin anomalies that make them heart-shaped, but we still have never seen anything quite like this one before,' Maclaine said.
'The general consensus is that it's a mutation, and probably more likely an out of place extra pelvic fin rather than a new dorsal fin," he said.
Comment: According to this report, the temperature in the area dropped from 38 C to -10 C in a matter of a few minutes.