A recently described butterflyfish has been reported for the first time from northeast Taiwan. Roa haraguchiae was described in 2020, but the only member of its genus represented in Taiwan until now has been Roa modesta. Most of the eight valid Roa species inhabit waters deeper than 200m and are usually only caught in bottom trawl nets. The type locality for Roa haraguchiae is in the East China Sea, Japan, but it’s also been found at Panay Island, the Philippines, and off the Pacific coast of Japan. The new location shows a range extension of some 1300 miles.
Roa can be identified by the three distinct bands on their bodies and make for super rare aquarium inhabitants because of the depth they are usually found at. The fish collected in Taiwan had some individual variations versus the type specimen of R.haraguchiae, but was later identified on the basis of morphology and genetic differences by life-barcoding. Roa butterflyfishes are rarely seen above depths of 50m but R.haraguchiae has been recorded in waters as shallow as 37m, in Kagoshima Bay, southern Kyushu, Japan.
The work was carried out by Ichthyologists at the National Taiwan Ocean University, and the paper published in Acta Ichthyologica et Piscatoria.