The longest living vertebrate in the world is the Greenland shark. It can be argued that the fact that they can live up to 500 years is due to the fact that they live in freezing cold water and therefore have a slow metabolism. So you can imagine how surprised some researchers were when they saw a Greenland shark (Somniosus microcephalus) haphazardly wandering around a coral reef off the Central American country of Belize.
This intriguing image marks the first time a sleeper shark (the shark family that includes Greenland sharks) has been identified in the western Caribbean. This interesting specimen was discovered by researchers from Florida International University’s Predator Ecology and Conservation Laboratory while working with local fishermen to tag tiger sharks.
“At first I was sure it was something else, like the well-known six-gill shark from the deep waters of coral reefs,” said FIU doctoral candidate Devanshi Kasana, lead author of the paper published in Marine Biology on the discovery. Fishermen who had never seen anything like it knew it.”
The six-gill shark would be an exciting discovery in itself, with its enormous size and more commonly found at depths of 2,000 meters. However, Kasana’s PhD advisor and Director of Sharks & Rays Conservation Research at Mote Marine Laboratory & Aquarium suspected something even more unusual: A Greenland shark.
Experts later confirmed that the mysterious animal was definitely from the sleeping shark family, but a definitive species could not be determined. However, being so large (between 3 and 3.5 meters) made the researchers suspect that it could be a hybrid with another large species, such as a Greenland shark or Pacific sleeping shark (Somniosus pacificus).
An ectoparasitic copepod (a type of crustacean) in the giant shark’s eye was another clue. Ommatokoita elongate, a 30-millimetre-long pinkish-white parasite, loves the corneas of Greenland sharks and is often found permanently fused to them. This works pretty well for researchers who are bad for Greenland sharks but sometimes try to identify them.
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