Diagnosis
Shell small, elongate-fusiform, with high orthoconoid spire and strong, tapering siphonal canal. Protoconch cyrtoconoid, brown, with four or more convex, glossy whorls. Spire whorls with flattened outline, sculptured by strong, orthocline axial ribs, forming characteristic adapical 'cap'. Spiral sculpture of regular stroke-like grooves, well pronounced in interspaces between axial ribs. Shell base strongly convex, rather short, siphonal canal moderately long, with very wide opening, sculptured by several strong oblique cords. Aperture elongate, outer lip smooth inside, with flattened adapical part; inner lip with four narrow, oblique columellar folds. Shell off-white, with contrasted pattern of fine orange to light-brown spiral bands on late teleoconch whorls, spire whorls with two bands, one adapical and one on periphery, just above suture, last adult whorl with third spiral band on shell base.

Description
Shell small, elongate-fusiform (w/h 0.35; a/h 0.46), with rather high conical spire and long, tapering siphonal canal. Protoconch conical, with 4.5-4.7 very slightly convex whorls, devoid of any sculpture. PI and PII not distinguished, protoconch/teleoconch transition distinct. Teleoconch of 7.0-7.5 adpressed whorls, almost cylindrical in early whorls. Suture wavy, distinctly impressed. Axial sculpture of fine orthocline ribs (17 on last adult whorl), with adapical part forming a distinct subsutural 'cap', giving the spire a slightly stepped appearance. Spiral sculpture of fine, evenly spaced, dashed grooves, pronounced in interspaces between axials below subsutural caps. Last adult whorl adpressed in its adapical portion and strongly convex below periphery, rather shortly constricted towards siphonal canal. Axial ribs reaching down to distinct waist delineating siphonal canal from shell base. Siphonal canal long and straight, tapering, sculptured by three very strong, rounded, oblique cords. Aperture elongate, outer lip thin, almost coaxial in its adapical third, convex at mid-height and slightly drawn abapically towards tip of siphonal canal; lacking lirae. Inner lip straight, bearing four columellar folds, adapicalmost strongest, apicalmost rather weak. Background colour white, four last teleoconch whorls with distinct, light-brown spiral bands formed by regular blotches in interspaces between axial ribs. Spire whorls with two such bands: one adapical and one just above suture. Last adult whorl with additional third band on shell base right above waist. Protoconch brown. Radula about 0.35 mm long and 0.08 mm wide, formed by about 47 rows. Rachidians tricuspidate with moderately wide base reaching about 40% of radula width. Anterior margin of rachidian base forming sharp blade-like edges on both sides of cusps. Three cusps of rachidian of about equal length, strong, pointed. Lateral cusps slightly elevated in relation to central cusp and directed slightly sideways. Laterals sickle-shaped, unicuspidate.

Alisimitra deforgesi differs from other species of the genus by the presence of spiral sculpture of dashed grooves throughout whorl height, whereas in most other Alisimitra species the spiral sculpture is confined to a single spiral cord on the adapical portion of the whorl. The other exception is Alisimitra fuscolineata in which the spiral sculpture elements are still more numerous than in Alisimitra deforgesi, and the shell base is notably more elongate. The other characteristic feature distinguishing Alisimitra deforgesi is its variegated colour pattern with distinct and contrasting colour bands.
Some deep-water Vexillum species, in particular Vexillum fuscovirgatum Herrmann & Salisbury, 2012 and Vexillum troendlei Herrmann & Salisbury, 2012 resemble Alisimitra deforgesi in shell proportions and colour pattern; however, both have undulating, arcuate axial ribs, notched siphonal canal, and outer aperture lp lirate within, whereas in Alisimitra deforgesi the axial ribs are straight, there is no notch at the tip of the siphonal canal, and the inside of the outer lip is smooth.

Papua New Guinea (Bismarck and Solomon Seas), Solomon Islands, New Caledonia (Loyalty Ridge), mostly on hard bottoms, depth range 389-556 m.