Very large (up to 200 mm in length), with eight teleoconch whorls. Protoconch of about two and one-half convex volutions, terminating in a weakly curved varix.
Spiral ornamentation on first two teleoconch whorls masked by axial ornament; third whorl with indistinct, brown-coloured cords at shoulder, periphery and suture. On fourth whorl, two or three major spiral cords with alternating minor ones. Body whorl and siphonal canal covered with regularly alternating primary, secondary and tertiary cords.
Axial ornamentation on first two teleoconch whorls of nine, sharply angulate ribs with short, open lamellar spinelet at shoulder. On third whorl every third rib strengthened into varix with long, closed spine at shoulder, intermediate ribs swollen, rounded, non-spinosc intervarical ridges. By fifth whorl, third axial ridge added at adapertural end of intervarical area. On later whorls, intervarical axial ridges increasing in number, but weakening in strength, until almost smooth on body whorl except for inconspicuous axial undulations on subsutural ramp. Three low, rounded varices per whorl, each with complicated arrangement of first, second and third order spines. Major spirals at intersection of varices drawn out into long, closed spines; shoulder spine strongest and recurved apically, that at periphery almost as strong but not so recurved; remaining major spiral cords each with long, closed spine almost straight but slightly curved adaperturally at distal ends. Secondary spiral cords produced into closed spines, somewhat shorter than those on major cords and more adaperturally directed. Tertiary spines almost as long as secondary ones, directed somewhat more adaperturally at approximately 45 ° to major spines. Spination pattern (anteriorly from suture) with tertiary, secondary, tertiary, primary (shoulder), tertiary, secondary, tertiary, primary (periphery), tertiary, secondary, tertian-, primary (base), tertiary, secondary. Siphonal canal with regularly alternating primary, secondary and tertiary spines; primary spines very long, recurved adaperturally at distal ends, the second from base of body whorl longest, succeeding spines progressively shorter anteriorly. Moderately long secondary spines alternate with primary spines and directed at about 45° to primary spines; small, needle-like, adaperturally-directed tertiary spinelets at 90° to primary spines. Suture very impressed, forming deep, narrow channel.
Aperture ovate: margin of outer lip crenulated by shallow depressions extending from grooves on varical spines. Labral tooth inconspicuous; anal notch shallow; posterior end of inner lip appressed, the anterior three-quarters narrow, free-standing, smooth. Siphonal canal long; previous canals fused into tube open by narrow slit; recurved at distal end; spinose for almost entire length. Colour creamy white to light tan, slightly darker immediately in advance of each varix; characteristically marked by having each spiral cord coloured reddish brown, intensity of colour relative to strength of cord with primary cords darkest; aperture white, with brown dots in crenular depressions; interior white. OPERCULUM. Reddish brown; subterminal nucleus with ten to twelve heavy concentric ridges; faint median crease along length.

There is little difficulty in separating the shell of M. troscheli from other species of Murex s.s. The large size, brown colour bands and impressed suture are characteristic. The type specimen of M. troscheli heros has been compared with typical M. troscheli and found to be essentially similar. Specimens from the Solomon Islands are very similar to the type of M. heros and are also very close to M. troscheli in all essential shell characters except shell thickness; relatively stronger varices, which are more deeply excavated abaperturally; shorter varical spines; and distinctly undulating spiral cords, which are coloured brown in the crests resulting in a dotted spiral cord in contrast to the solid colour in the typical form. We conclude that M. heros is not specifically separable from M. troscheli. It is probable, however, given more material and better distributional data, that a case could be made for recognising M. heros as a geographic subspecies. Radwin & D'Attilio (1976) include M. heros in the synonymy of M. troscheli without any discussion.

Indopacific.