Medium-sized, b/1 0.32-0.33; aperture much shorter than spire (a/1 0.37-0.39), spire somewhat cyrtoconoid (initially orthoconoid), suture shallow, not channelled, whorls with projecting, rounded peripheral angle; anal sinus deep with slightly constricted opening. Spiral cords rounded, without sharp edges. Subsutural cord ill-defined (forming a weak ridge on early whorls), sulcus broad and gently concave, sinus cord with low, lunulate crenules; base of each whorl with a single rounded cord, showing at periphery of last whorl; base of last whorl with 3 rounded, weakly nodose cords, weakening anteriorly, subequal in width to their intervals; rest of base and rostrum with 10-12 anteriorly weakening spiral ridges, obsolete on base, sometimes with irregular intermediary threads. Spiral cords incised by growth lines, of which intermittent ones form weak, rounded nodules. Microscopic spiral threads overall, most distinct below suture. Protoconch blunt (protoconch I fairly large), of 2 whorls, maximum diameter 1.4-1.6 mm, smooth, with terminal growth lines only. Cream-colour, sometimes with diffuse brown spots, periostracum not obvious. Shell attains 45 mm.

Diagnosis: Medium-sized (4,5 cm), aperture 0,37-0,38 total length, spire somewhat cyrtoconic, whorls with projecting, rounded peripheral angle; shoulder sulcus broad and gently concave, subsutural cord weak and ill-defined, shoulder cord with lunulate crenules; basal periphery with 3 thick, rounded cords; protoconch of 2 whorls, maximum diameter 1,4-1,6 mm, with terminal growth-lines only; cream-colour, sometimes with diffuse brown spots.
Description: Shell with 9 teleoconch whorls, aperture much shorter than spire (0,37-0,38 total length), spire initially orthocline, later slightly cyrtoconic, whorls becoming progressively more angular with growth; sutures shallow, not channelled. On first 6-7 teleoconch whorls subsutural cord forms a weak ridge, sometimes bifid, delimited by a shallow sulcus; on later whorls the cord becomes progressively feebler and the shoulder sulcus wider and gently but distinctly con¬cave. Anal sinus deep, sometimes constricted at opening, forming a series of low, lunulate crenules (about 38-40 on penultimate whorl) on shoulder cord; this cord initially develops as a pair of lirae bearing corresponding sets of crenules, which ultimately merge; in the adult the shoulder cord is relatively weak, little stronger than the subsutural one. Subsutural cord, shoulder sulcus and shoulder cord bear fine spiral striae and arcuate, prosocline, growth-lines. Periphery of base with 3 thick spiral cords of which the upper and most of the second show above sutures, the upper being massive and forming the peripheral angle of spire whorls, whereas the two anterior cords are progressively weaker, with concave intervals, subequal in width to them. Rest of base and rostrum with 10-12 anteriorly weakening spiral ridges crossed by coarse growth-lines, sometimes with irregular intermediary threads. All cords and ridges anterior to main peripheral one may develop weak granules. Surface somewhat porcellaneous, without evident periostracum. Yellowish-white, ridges often with diffuse spots of light to strong brown, situated mainly between granules and crenules; protoconch white. Protoconch bluntly conical, of about two whorls, the first being relatively large; smooth except for a short terminal series of arcuate growth-lines; maximum diameter 1,4-1,6 mm. Dimensions: 44,5 x 14,4 mm (holotype); 49,7 x 15,9 mm (paratype). Radula: Rachidian large and rather quadrate, with a small mesocone only; marginal plates with both arms very long and slender.

Turris ruthae somewhat resembles T ambages, but has much more angular whorls, a less abbreviated base, more rounded spiral cords with wider intervals, a wide, evenly concave (instead of narrowly channelled) sulcus, and a less distinctly differentiated subsutural cord; the protoconch, too, differs in size and in other respects.
The shape of the marginal teeth of the radula is unique within Turris (see Kilburn (1983)), and may indicate the species to belong to a distinct genus.

South-east Africa, on outer continental shelf and upper slope of southern Natal and Transkei, from Scottburgh to near East London, 70-150 m, mainly on coarse sand and sponge bottoms.