Scientists Discover Some Clingfish Species Are Venomous

Posted on May 15, 2014

A new species of clingfish has been discovered. Scientists have also discovered that some Caribbean clingfish species are venomous. Dr. Kevin Conway, assistant professor and curator of fishes with Texas A&M's department of wildlife and fisheries sciences at College Station, and his team discovered the new species, Acyrtus lanthanum (pictured above), in shallow water along the coast of Belize and islands in the Caribbean and Bahamas.

Conway says clingfishes get their name from their ability to anchor themselves using their large belly sucker. To identify the new clingfish species the team had to examine other closely related clingfish. During their examinations they found several species of clingfishes have a strange gland.

Conway says, "During that comparison process we discovered that several species of Caribbean clingfishes, but not the new one we found, have a strange gland associated with a very sharp and spine-like subopercular bone, one of four bones that support the gill covers in fishes. The cells inside the gland are incredibly similar to those present inside the venom glands of scorpion fishes and certain catfish and based on this similarity, we are confident that these clingfishes are also producing some type of toxin."

The image above shows venomous (right) and non-venomous (left) Caribbean clingfish. The image also shows the differences in the subopercular bone.

Conway says most of the world's 2,000-plus venomous fish species deliver venom using a "modified fin ray, sharp opercular spine or even through a large fang in their lower jaw." The venom gland they discovered in the Caribbean clingfishes associated with the subopercular gill cover bone is the first of its kind to be discovered.

Conway says, "We do not know exactly what the venom is used for, but based on the position of the venom gland, it is more likely that it would be used for protection, as in most venomous fishes. We don't yet have any information about the toxic properties of these clingfishes, but we hope that our discovery will encourage other scientists to take a look at the venom gland we discovered in more detail."

The research is published here in PLoS One.

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