Shell of medium size for the genus , height: 5-15 mm, mean: 9.7 mm, width: 2.3-5.6 mm, mean: 4 mm. Thin subfusiform, H/W: 2.10-2.70 mean: 2.37.
Protoconch paucispiral only protoconch I of 1.4 convex whorls, height: 448 µm, width: 388 µm variable in shape and size: more or less elated with more or less protruding nucleus. Sculpture irregularly cancellate.
Protoconch-teleoconch boundary slightly indistinct but flexuose with scattered microgranules. Teleoconch of 5-7 [6] convex whorls, weak suture and low sculpture, with inflated last whorl. Microgranules on the first half whorl. Axial sculpture of 14-32 [22] slightly opisthocline ribs, and interspaces of irregularly variable size. Spiral sculpture on the last whorl of 6-8 [7] cordlets above the aperture, slightly narrower than the axial ribs. Cancellation rectangular to subquadrangular, with small and acutely papillose tubercles at the intersectios. Sculpture visible in transparency throughout the thin internal shell wall. Subsutural ramp narrow. A very small cordlet at the edge of the ramp with acute papillae. Anal sinus as wide as the ramp but not deep. Columella simple, sligthly sinuose on its medial part.
Siphonal fasciole indistinct, with 8-10 weakly nodulose cords. Outer lip with 9-15 [12] strong inner denticles sometimes bifid, the second most anterior stronger. Siphonal canal wide and short. Coloration of variable hues of brown, with wide neatly delimited white blotches. Entirely white specimens known. Occasional white comma-shaped spots on the subsutural ramp. Protoconch generally darker than the background.
Soft parts white (Cecalupo et al, 2008: 124).

It is a typical species of the Gulf of Gabes fauna, along with R. arnoldi and R. pruinosa with which could be mixed. It is the most common of the three, with the less fragile shell (yet the papillose tubercles become rapidly blunt in beached specimens), very variable in shape, sculpture (with a peculiar rectangular to subquadrangular cancellation) and coloration. R. pruinosa is easily distinguished by its keeled protoconch the very narrow subsutural ramp, the more numerous axials (30-38 vs. 14-32) spiral cordlets (9-12 vs. 6-8) and inner denticles in the outer lip (15-18 vs. 9-15). R. arnoldi has also a very similar protoconch, but is easily diagnosed by the more slender outline, the wider cancellation, the lack of a true subsutural ramp (replaced by a weak shoulder).
R. papillosa differs from R. philberti for its more fragile shell, the more numerous axials (14-32 vs. 15-20), the thinner spirals, the acute papillose tubercles (vs. elongate tubercles), the slightly wider subsutural ramp, and the lack of withish blotches vanishing towards the suture.
R. papillosa differs from R. alternans by its less slender outline, the less fragile shell, the more incise suture, the broader subsutural ramp (very narrow in R. alternans), by its colour pattern never with vertical white blotches (always present in R. alternans).

Considered as endemic to the Gulf of Gabes, sporadic records from Lampedusa Is. and Sardinia seem to witness a range wider than supposed. Conversely the record from northern Adriatic by Cesari & Mizzan (1994) is not deemed to be reliable. Manousis (2012) recorded this species from Saroniki Gulf and confirmed (com. pers.) that he had personally collected it. Found living in shallow water (Gabes) under stones or amidst residues of algae or Posidonia's rhizomes.