- Holotype: TKPM-P 17335.
- Paratypes: (5/5): KPM-NI 31986, 31987, 31984, 31982, 31985, 31981, 31983; TKPM-P 17336, 7360.
Type locality: Takazaki River, Oyodo River system, Takaharu, Miyazaki Pref., Kyushu Island, Japan.
Etymology: The specific name sakahoko is derived from the legendary weapon Ama-no-sakahoko (= inverted halberd of heaven), which was thrust into the Takachiho Peak of Mt. Kirishima, one of the sources of the Takazaki River, the type locality of this species. The lamina circularis of this species is a distinctive rectangular plate that resembles a halberd.