While combing through specimen collections in Japan, scientists came across three unusual-looking fish.
The tiny, brightly colored creatures had been collected from Mageshima Island and Nagannu Island, and although they were identified as Opistognathus, a genus of jawfish, their species was unknown.
That’s when researchers discovered that the creatures were actually a new species: the Japanese whitespotted jawfish, or Opistognathus ctenion, according to a study published Sept. 14 in ZooKeys.
Scientists said Opistognathus is the most speciose genus of jawfish, with populations in tropical and temperate waters except for the eastern Atlantic Ocean and Mediterranean Ocean. The fish are difficult to study because their small size and “cryptic habitat” make them hard to catch.
The three specimens of Japanese whitespotted jawfish range in size from about 0.68 inches to 1.2 inches. They have long, compressed bodies, cylindrical heads and somewhat large eyes, according to the study. Their noses are short and tube-like.
Researchers said the specimens range in color from reddish-brown to yellow. Photos show the two fish collected from Mageshima Island are more orange while the single specimen found near Nagannu Island is yellow.
All of the specimens have distinct white blotches on their cheeks and the sides of their bodies, scientists said. Their irises are reddish-brown and their pupils have four dark red lines extending from the center.
The habitat of the fish is hard to distinguish, but the specimen collected from Nagannu Island was found at the sandy, gravel bottom of the ocean, the study said. All of the fish were found between about 115 feet and 187 feet underwater.
Researchers said they named the species after the Greek word for “small comb” because of the low number of gill rakers — which protect their gills — the fish have compared to other species of Opistognathus.
Both islands are south of Japan. Nagannu Island is about 370 miles south of Mageshima Island.