Researchers Have Discovered That Stonefish Pack a 'Switchblade' in Their Face

Biologists have discovered a new feature belonging to stonefish: a switchblade-like sabre embedded in their cheeks, which springs out whenever the fish feel threatened. The blade is commonly referred to as a lachrymal saber, which literally means “concerned with tears”.

William Leo Smith from the University of Kansas discovered the weapon after dissecting a dead wispy waspfish he kept as a pet. The revelation was unique because “only a couple of researchers have really looked at the anatomy of this group,” Smith told Discovery magazine.

Some Stonefish are among the most venomous fish in the world, as well as possessing a defensive artillery that includes venom, thorny spines, and camouflage. The recently discovered hidden blade can flick out in a variety of angles, extending out around five centimeters. Smith warns that "[Stonefish] can easily kill an adult human…defensiveness has just run amok in this group."

According to Marine biologist Julian Pepperell, Australia has two species of deadly stonefish: the estuary stonefish and the reef stonefish. Although they are incredibly venomous, stings are actually quite rare. And although there have been deaths overseas, there have been no recorded deaths in Australia.

As well as functioning as a defensive mechanism, the stonefish blade glows like a light sabre, which may indicate a variety of other functions. “It could play a role in mating, mate attraction, or territory defense,” Smith explained to WAToday.

The sabre has been an important revelation for scientists, who claim that the blade is a defining feature for the species. The sabre is common to each of the 134 species of stonefish, which provides biologists with a simple format for classifying them. “The readily apparent feature allows new species to be immediately recognised as members of this group,” Smith told WAToday.

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