Description (based on Recent specimens from the Philippines): Shell thin, fragile, consisting of 9-9.5 teleoconch whorls, relative spire height 18-26% (mean 22.5%), diameter/height ratio 39-45% (mean 41%). Axial ribs forming prominent knobs on first 4-5 whorls, gradually disappearing on 5th-6th whorl, last 2-3 adult whorls devoid of axial sculpture. Subsutural ramp very broad, distinctly concave and smooth on first whorls; as axial sculpture becomes obsolete on subsequent whorls, the ramp also becomes progressively more flat, and is occupied medially by 4 strong smooth ridges separated by deep grooves. Last adult whorl regularly convex, position of ramp marked only by presence of spiral ridges/grooves, periphery rather smooth, base with unevenly spaced spiral grooves. Siphonal canal comparatively longer than in other species, curved adaxially. Dimensions 21.2 x 9.6 to 29.7 x 12.6 mm.

Recent shells differ slightly from fossil specimens as described and illustrated by MacNeil (1961) in having a stronger group of spiral grooves in the middle of the subsutural ramp, usually broader spiral cords in the basal part of the last whorl, a smooth surface below the periphery on the last few whorls, and a narrower callus on the inner lip. These differences are minor and seem to be within an acceptable range of variation.
Buccinaria martini resembles B. loochooensis in its spiral sculpture, but its shell is more solid, with a much deeper anal groove. Specimens of B. loochooensis from the Philippines differ from specimens of B. martini from Indonesia in being more slender, with transparent rather than greenish periostracum. However specimens of B. martini from geographically intermediate localities (Albatross stations in Sebuku Bay) have similar proportions (diameter/height = 46-50%) and resemble each other rather much; in such samples, B. martini however remains clearly separable by its deeper anal groove, and axial costules crossing over spiral cords in the adapical portion of whorl. It could be conceived that martini clines into loochooensis if it were not for the occurrence of typical specimens of martini in the Philippines ("Albatross" sta. 5446) and Japan. B. loochooensis also resembles the Pliocene B. tobaruana (Noda, 1988: 59, pl. 11, figs. 5a-5b [not 13a-13b as indicated in the original description and captions; the descrip¬tions of B. miyagishimana and B. tobaruana suggest that their illustrations were transposed]). B. tobaruana is characterized by weak spiral grooves on the subsutural ramp and by the presence of axial riblets below the suture, but these differences probably do not mean much. Evaluation of intraspecific variability of B, tobaruana may reveal it to be conspecific with B. loochooensis.

Distribution: Pliocene of Okinawa (Ryukyu Islands). Recent, from Luzon Island (Philippines) to the Celebes Sea (Indonesia), shells in 416-702 m.