Ancilla thomassini Kilburn, 1981 [Invalid]

"Diagnosis: Shell very small (up to 7 mm); oblong-fusiform (breadth/length 0,44-0,50), base contracted, spire moderately high, angle 46°-63°, blunt, aperture/total length 0,58-0,70; sutures distinct; ancillid groove deep, forming a distinct tooth, followed by a notch; ancillid and fasciolar bands declivous; columella pillar short, with 3-4 subequal lirae; pure white to pale orange-yellow with a white fasciole and a diffuse orange line below suture.

Description:
Quantitative (N = 32):
Breadth/length: 0,44-0,50 (M = 0,47; SD = 0,02)
Aperture/total length: 0,58-0,70 (M = 0,64; SD = 0,03)
Spire angle: 46°-63° (M = 56,5°; SD = 4,6°)
Maximum dimensions: 7,1 x 3,2 mm
Minimum adult dimensions: 4,6 x 2,2 mm

Shell oblong-fusiform, extreme base slightly to strongly contracted, greatest width median, left side of body whorl slightly more convex than right, labrum sometimes slightly shouldered; spire moderately high, usually orthoconic, sometimes slight coelo- or cyrtoconic, whorls slight convex, sutures masked by a callus glaze, but usually somewhat indented, particularly on right side just above termination of labrum. Aperture with greatest width just anterior to middle, acutely tapering posteriorly, curved anteriorly; siphonal canal wide, very shallowly notched, base almost straight. Columella pillar short, only about 0,45-0,51 length of labium, moderately twisted, its inner margin almost straight, with a shallow basal notch; lirae 3-4, fairly strong, subequal, the outer one demarcated by a slightly wider interval than the others. Paries gently convex, without a distinct callus, ridge or scar: Ancillid groove deep, terminating in a distinct labral tooth; ancillid band slightly declivous and rather wide, at labium subequal to fasciolar band in width; fasciolar band declivous, rather thick, flattened, anterior fasciolar groove shallow. Smooth, except for a few growth lines behind labrum, and very fine, indistinct microshagreen sculpture that is visible between columella pleats, along siphonal border of fasciole and along labral rim. Labrum fairly thick, often with a small notch anterior to labral tooth; in side view prosocline and almost straight. Teleoconch whorls 2,5. Protoconch (Fig. 58) narrowly domed, 1,25 whorls, initial one rather large, maximum diameter 0,8 mm. Either uniform white or light orange-yellow, with a diffuse darker orange line posteriorly, separated from suture by a series of faint, whitish blotches; fasciolar band and columella white. Operculum transparent and almost colourless, surface with growth lines and faint radial striae; 0,61-0.68 of aperture length. Radula with tricuspidate rachidian plate, main cusps rather small, median cusp longer than side ones, intervals rather wide, intermediary denticles sharp, 1-2 per side; lateral plates with a slender base and subequal uncinus.".