Type locality of Haptenchelys parviocularis, Honshu, Wakayama, off Kii Peninsuala. Known only from the Pacific abyssal zone off southern Japan, in depths of 2,830-4,866 m, and all of the recorded sites are located along the northern part of the Philippines Sea Plate: to the East, from the Ogasawara Trough (off Bonin Islands), part of the Izu-Bonin-Mariana Arc; to the North, from the Nankai Trough (off Zenisu, Kii Peninsula, and Kochi); and to the West, from the Ryukyu Trench (off Okinawa Island) (Ref. 96071).