Shell large (up to 115 mm in length), with up to eight teleoconch whorls.
Protoconch of about three conical volutions, last two with sharp keel adjacent to suture, terminating at sharp, crescentic varix.
Spiral ornamentation absent on first two teleoconch whorls; on third whorl two extremely weak spiral cords, one at shoulder, other at periphery. On fourth whorl, three even weaker secondary spiral threads, one on subsutural ramp, one between primary cords and third between suture and periphery. Number of spirals increase by intercalation on subsequent whorls, until body whorl and siphonal canal covered with alternating primary, secondary and tertiary cords, all flattened and relatively weak.
Axial ornamentation on first two teleoconch whorls of eight or nine ribs, flattened on subsutural ramp and drawn out into two almost closed, lamellar spinelets, one at shoulder and slightly smaller one at periphery. On third whorl every third axial rib strengthened into varix with moderately long, slightly open, apically curved shoulder spine; smaller spine at periphery; two intervarical ribs reduced to low rounded ridges lacking spines. On fourth whorl, third axial rib added at adapertural end of intervarical area. Intervarical ridges added, but weak on subsequent whorls until, on body whorl, there are five very low, rounded axial ridges marked mainly by weak elongate nodules where crossed by spiral cords. Three low varices per whorl, each with three, usually short, slightly apically recurved (but not so much as on earlier varices) primary spines. Three smaller, straight, secondary spines alternate with primary spines and directed approximately in same plane as primary spines, although, between shoulder and peripheral spines, usually no spine developed. Spination pattern typically (anteriorly from suture) of primary (shoulder), primary (periphery), secondary, primary (base), secondary, Siphonal canal with about four short, straight primary spines; juvenile specimens with five, or occasionally six, such spines. Alternating with primary spines on canal are tiny, adaperturally directed, secondary spinelets at right angles to major spines.
Suture simple, crossed diagonally by numerous growth lamellae appressed against anterior portion of preceeding whorl.
Aperture ovate; outer lip margin notched, with centres of notches recurved into grooves of primary and secondary spines, giving low, rounded, forwardly-directed projections. Projection posterior to major spine at base of body whorl drawn out into very large labral tooth. Posterior end of outer lip formed by projecting shoulder ramp, with the truncated remnant of peripheral spine from preceding whorl fused into it. Shoulder ramp forms outer margin of anal notch. Posterior third of inner lip strongly appressed, flared, with flare extending onto preceding whorl to level of secondary spinelet between shoulder and peripheral spines, this extension forming relict structure on preceding whorls. Anterior two-thirds of inner lip narrow, freestanding but flattened against columella. Siphonal canal moderately long; terminations of previous canals fused into straight lube, open by narrow slit; about one-half total length spinose. Colour yellow-tan with bluish tinge between spiral cords; aperture white at margin with brown interior, occasional darker brown lines terminating at grooves in spines.

Indian Ocean and West-Pacific. It is very abundant in shallow water in parts of southeastern Asia.

This is a distinctive species characterized by 1) fusiform, moderately high-spired shell up to 115 mm in height, 2) teleoconch whorls angular, with the periphery about at the adapical one third, meeting at adpressed sutures, 3) body whorl globose, tapering at the base and with long, straight neck, 4) aperture oval; outer lip somewhat flaring, bearing rounded projections; inner lip thinly callused, expanded adapically, then detached from the columella; siphonal canal long, open by a narrow slit, 5) sculpture of collabral ribs overridden by spiral cords; 3 varices per whorl bearing recurved, moderately long spines; spines are also noted over the adapical one half of the neck. According to PONDER & VOKES (1988), Murex trapa is distinguished from the other related species on the basis of 1) higher spire, 2) angulated whorls and 3) shorter spines. DISTRIBUTION AND HABITAT. The species is distributed from Madagascar to the Fiji Islands and northward to China and the Ryukyu Islands (PONDER & VOKES, 1988). It is a mainly subtidal element, occurring on fine sandy and muddy bottoms in the 5-60 m depth range. WAY & PURCHON (1981) recorded it presence on intertidal sands with rocks along the Malayan shores. Previous records in the Gulf of Thailand were from sand and muddy sand between 5 and 10 m depth (SWINNEN et al, 2001). Examination of gut samples (specimens trawled from Tolo Channel, Hong Kong) revealed molluscan, crustacean, and polychaete remains and fish scales (TAYLOR & SHIN, 1986). FOSSIL RECORDS. Middle and Late Miocene of Indonesia; Pliocene of Indonesia, Philippines and Taiwan; Quaternary of Indonesia; Holocene of Thailand.

The relationships of this species may be with the M. scolopax species group, which it resembles in most shell characters except for having a 'closed', not 'open' outer lip. It is included in the M. tribulus species group, which is undoubtedly heterogenous, because of this character and because of its resemblance to some forms of M. aduncospinosus.
The shell of this species is readily distinguished by its tall spire, angulated whorls and short spines.