As adults, male Gnathia marleyi don’t eat, they just mate and die. (Credit: John Artim)

The tiny adult male marleyi, on which the new species description is based, don’t eat. They just mate and die. Sikkel followed the species through its life cycle in the lab.

“The adult males look a little bit like bulldozers," Sikkel says. "They have square heads. They have pincers on their head and they are very cool-looking. And the females have a small head and a really big body that’s full of eggs."

About 80 percent of all organisms found on coral reefs are parasites, with gnathiids among the most ecologically important. Sikkel says the concentration of gnathiids can be an indicator of how healthy a reef is. At some of his research sites, he is seeing fish more heavily covered with gnathiids - marleyi among them.

“Too many gnathiids hurt the fish and too little coral, we think, leads to more gnathiids," Sikkel says. "So in a nice, healthy coral rich environment, we don’t find many gnathiids, fish just get a few of them. But in areas where there isn’t too much live coral, there are more gnathiids and the fish get heavier loads on them.”

Juvenile gnathiids collected and observed in the laboratory after feeding on fish blood. (Credit: Ann Marie Coile)

Sikkel suspects that Gnathia marleyi may also play a role in transmitting a malaria-like disease that weakens the fish's immune system. His team is currently studying whether this pathogen, found in gnathiids on other reefs, is also present in the Caribbean.