The shell is of medium size, ovate, somewhat inflated, opaque and glossy. The terminals are slightly produced and protruded. The dorsum is roundly elevated without a dorsal furrow or depression. The sides are rounded. The ventrum is convex with a weak, very obtuse-angled, rounded keel connecting the posterior end of the left wall of the anal canal with the left wall of the siphonal canal. The aperture is fairly narrow, almost straight but somewhat curved at the posterior end. The canals are weakly indented. The columella is slightly, convexly curved with a barely developed inner adaxial carinal ridge. The fossula is concave. The fossular edge is excavated and partly covered by the labium. The inner edges of the fossula and columella are separated by an indentation. The labrum is rounded, narrow, broadest at the mid-portion, posteriorly excavated and anteriorly declive. The outer labral margin is curved and rounded. The inner edge is wavy-like. The dorsal ribbing - 24 on average (varies between 20 and 26) - is numerous and close-set. They are continuous from the dorsal elevation becoming more numerous over the side margins, ventrum and labrum. They terminate as sharp, fine teeth on the inner labral edge - 23 on average (varies between 20 and 27). The ribs continue on the columella becoming somewhat finer on the columellar wall. They - 19 on average (varies between 18 and 20) - are not thickened on the well-developed somewhat edged parietal lip. The parietal lip is sinuous. The shell color is white overall.

EXTERNAL MORPHOLOGY
The animal of Trivirostra turneri was described by Liltved (2000: 185) - here mistakenly identified as Trivia pellucidula (Gaskoin,1846) and probably mixed up with animals of Trivirostra natalensis Schilder,1932 and Trivirostra triticum Schilder,1932. His description does not agree with his picture (Liltved. 2000: text fig. 287) of a living animal. He wrote. "The mantles ... varied from orange, drab green or brown ... Overlying amorphous opaque-white patches and sparse linger-like and simply branched papillae were present on all specimens examined. The elongate cylindrical siphon was similarly colored to the mantle and was also covered with dense or sparse wart-like papillae. These tended to be most densely concentrated along the lateral portions of the fully extended mantle. The slender translucent cephalic tentacles were pigmented with dense sulphur-yellow streaks and the narrow elongated foot possessed a superimposed pattern of fine opaque-white thread-like reticulations."
The animals of T. turneri found at the Red Sea offshores were similarly colored and sculptured as in Liltved's figure but black colored specimens - mentioned by Liltved also for "Trivia pellucidula" - could be only confirmed for T. natalensis and simply branched papillae are only seen in T. triticum. Therefore, it is necessary to present here a new description of the external morphology of T. turneri: The mantle lobes are translucent white overlaid with brown or greenish irregular blotches and spots of various sizes and darkness. There are two darker and larger blotches towards each shell terminal that are running into one another sometimes. The mantle is sparsely covered with short finger-like papillae that show rarely the trend to short branches on the top. The tips of the translucent papillae are bright yellow. The long, slender and cylindrical siphon is translucent with dense long, bright white stripes, some brown blotches and few wart-like papillae with bright yellow tips. The cephalic tentacles are translucent with sulphur-yellow streaks and blotches. The long, slender and transparent foot is superimposed with fine, bright white thread-like reticulations.

Trivirostra turneri Schilder. 1932 belongs normally to the group within the genus with no dorsal sulcus or depression. Other species without a dorsal depression are Trivirostra pellucidula (Gaskoin. 1846) from the central Pacific to the eastern part of the Indo-Pacilic. Trivirostra vayssierei Cate. 1979 from the W Indo-Pacilic and T. corrugata from the whole Indo-Pacific. However, within the large samples from the Red Sea we found also specimens with an unusually slight dorsal depression that cannot be observed in specimens occurring at southern Africa. T. turneri is very easy to distinguish from T pellucidula by the shape and position of the aperture - it is sinuous, very narrow and in the shell center at T. pellucidula - by the more coarse, less numerous ribs and denticles, by the less developed, not so broad columella and fossula and by the shorter terminals. T. vayssierei looks more similar to T. triticum but is generally smaller and the terminal tips are protruded or at least flattened but never indented. Trivirostra turneri is. therefore, distinguished from T. vayssierei by the whole shell morphology and the size although it has similar terminal tips. T. turneri is separated from T. corrugata by the larger size, the broader aperture, the shorter terminals, the regular arranged dorsal ribs and the lesser developed columella and fossula.