Stonefish are already known for being extremely dangerous due to them being highly venomous and researchers just discovered something else about them that is a bit shocking, they have a defensive switchblade-like system on their face.
In a new paper published in the journal Copeia, marine biologist dive into the discovery that has not been noticed till this point. The switchblades are a facial spine that flicks out at will called a lachrymal saber.
The discovery first started in 2003 when one of the researchers was dissecting stonefish he had kept as a pet. While performing the dissection, he noticed that underneath the eye, there was a modified bone that could flick out, with the underside of it interlocking with another piece of bone on the fish’s face.
The two bones work like a ratchet, allowing the blade bone to lock into position at different angles. Upon further investigation, the researchers learned that it wasn’t just the bones that had been modified through evolution, but the blades also had a while host of muscles and ligaments attached to them too.
“There can’t be any other reason for those muscles and ligaments except to control this mechanism,” explains William Leo Smith, who made the discovery and is associate curator at the KU Biodiversity Institute and Natural History Museum, in a statement. “This whole group of fishes is called the ‘mail cheek fishes’ or Scorpaeniformes, where the bones under the eye attach to the gill skeleton. Because all these muscles are attached to the gill skeleton, it allows for all this force which causes the lachrymal saber to deploy.”
The researchers believe that the switchblade isn’t a mechanism used for fighting but rather it is a defensive system. When a larger predator comes to prey on the stonefish, the bone-blade will flick out to make swallowing difficult.