A team of ichthyologists from the Kagoshima University and the Kagoshima University Museum has discovered a new species of the fish genus Pteragogus living in Indian and Pacific oceans.
Underwater photograph of the thrush sneaky wrasse (Pteragogus turdus), adult individual, Ishigaki-jima Island. Image credit: K. Nishiyama.
Pteragogus is a relatively small genus of ray-finned fishes in the wrasse family Labridae.
The genus includes over 10 scientifically recognized species which are widely distributed.
They are native to the Indo-West Pacific, the Red Sea to South, Papua New Guinea, northern to southern Japan, the shores of the Korean Peninsula, and south to Australia.
“Members of Pteragogus can be divided into three groups according to the number of dorsal-fin spines,” said Kagoshima University’s Dr. Tomoka Iino and Kagoshima University Museum’s Dr. Hiroyuki Motomura.
“The newly-identified species falls into the group with 10 dorsal-fin spines.”
The researchers described the new species on the basis of 65 specimens caught in Indian and Pacific oceans.
Named Pteragogus turdus, the species has a length of 6-8 cm (2.4-3.1 inches), a reddish-brown head and body, and pale brownish-white scale margins, forming indistinct reticulated pattern.
The fish is most similar to Pteragogus cryptus, both species having previously been considered as a single species.
“However, Pteragogus turdus can be distinguished from Pteragogus cryptus by the lower number of total gill rakers, shorter 10th dorsal-fin spine, slightly shorter pelvic-fin soft ray, and filamentous membrane tips on the anteriormost two or three dorsal-fin spines in terminal phase males,” the authors said.
“In addition, the new species inhabits the waters of the eastern Indian Ocean (Western Australia) and western Pacific Ocean (Japan, Taiwan, Thailand, Vietnam, Philippines, Palau, Micronesia, Indonesia, Papua New Guinea, Solomon Islands, eastern Australia, New Caledonia, Fiji, Tonga, and Samoa) whereas Pteragogus cryptus is restricted to the western Indian Ocean.”
The discovery is described in a paper published in the journal Ichthyological Research.
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T. Iino & H. Motomura. Pteragogus turdus, a new species of wrasse (Perciformes: Labridae) from the Indo-West Pacific Ocean. Ichthyol Res, published online April 30, 2022; doi: 10.1007/s10228-022-00875-0
