Diagnosis: Shell with a solid porcellaneous texture, long siphonal canal and a double keel on the last whorl. Numerous columellar folds and strong spiral ridges inside the outer lip.
The protoconch is not discernable, as the very top is broken off and there is no indication of the start of the teleoconch. Spire whorls are 5, all sharply keeled. On these whorls there are about 6 to 8 spiral ridges above the keel, which become more visible towards the later whorls. Suture very deeply incised and with a subsutural channel. On the body whorl there is a secondary keel, the interspace between the primary keel and the secondary keel is strongly concave and bears three strong spiral ridges. The primary keel is hollow and open. It appears to consist of two plates covering each other with a small interspace. From the secondary keel down to the end of the siphonal canal there are about 11 strong spiral ridges over the entire last whorl. Aperture elongate and wide above, it becomes gradually constricted below. Siphonal canal long and hollow with a fasciole and an open umbilicus. Columellar callus glossy, thick, with 20 very weak folds. Peristome not interrupted. On the inside of the outer lip 12 strong spiral lines that develop nearly into knobs about 2 mm from the peristome. Overall color pale purple-brown without any pattern. Inside of the aperture covered with a glossy callus in which we discern shades of white and purple. TYPE MATERIAL Holotype: Height 29.7 mm. Diameter 21.3 mm. Coll. NMP, Manila.

Different from all Turbinellids we could study. Because of its unusual appearance and shape, the closest related species we could find arc Tudicla zanziharica Abbott. 1958. Tudicla armigera (A. Adams. 1865), Tudivasum biennis Angas. 1878 and Tudivasum spinosa. Enigmavasum enigmaticum differs from all these by the absence of spines on the body whorl, the double keel and the first keel that is hollow. E. enigmaticum has such a strange shell that it is conchologically difficult to assign to a family. The closest conchological relative is Tudivasum spinosa A. & H. Adams. 1863. This shell has similar folds on the columella, inside the outer lip, in some specimen a well-developed keel and a subsutural channel as in E. enigmaticum. We therefore place the species in the family TURBINELLIDAE which now contains the former VASIDAE (Harasewych, 1998). Studies of the animal may refer the genus and the species to another family in the future. A resemblance with certain CORALLIOPHILIDAE and MURICIDAE is superficial and the shelly, solid porcellaneous material of the shell of E. enigmaticum is unknown in those families.

TYPE LOCALITY: Cotabato Province, Philippines.
E. enigmaticum was taken at a depth of 800 m. The shells fished together with E. enigmaticum suggest a mud bottom. Among those were Benthovoluta krigei Kilburn, 1971, Pseudastralium henicus (Watson, 1879) and two species of Nassaria .