Little is known about this small Granulifusus species (22.5 mm), only represented by the holotype attached to a Xenophora specimen. This species was erroneously placed in Colubrariinae by SUBBA RAO & DEY (2000: 134) as Fuscus captinus. Judging from the holotype figured by ALCOCK & MCARDLE (1901: pl. 10, figs. 8, 8a) we conclude that Fusus captivus is a distinct species belonging to Granulifusus.
G poppei most closely resembles in shape and sculpture, but differs by its larger shell size, the longer siphonal canal, the larger number of primary spiral cords on the upper whorls, and the more close-set spiral sculpture.
The deep-water form of G. kiranus from Taiwan is similar in shape and sculpture, but differs by its larger shell size (up to 45 mm), the uniform white shell, the smaller aperture and the longer siphonal canal.