Imbricaria, SCHUMACHER, 1867

GENUS IMBRICARIA SCHUMACHER, 1867 View in CoL

( FIGS 24, 25A–H)

Type species: Imbricaria conica Schumacher, 1817 (= Mitra conularis Lamarck, 1811 ); M.

Synonym: Conoelix Swainson, 1821 . Type species: Conoelix lineatus Swainson, 1821 (= M. conularis Lamarck, 1811 ); OD.

Diagnosis: Shell small to medium sized (10–55 mm), fusiform, narrowly biconical to nearly conical, uniformly coloured or with variegated pattern. Protoconch narrowly conical, of three or more slightly convex or flattened, smooth and glossy whorls. Early teleoconch whorls forming narrowly conical apex; later whorls widening at equal rate, resulting in fusiform or biconical shell, or (typically) at increasing rate, resulting in acuminated spire and slightly inflated or conical last adult whorl. Early spire whorls sculptured with rounded spiral cords; late whorls smooth or with spiral cords, the latter wide and rounded or fine and sharp, sometimes bearing regular tubercles. Interspaces between cords smooth or with fine, dense riblets. Siphonal canal tapering, with distinct siphonal notch. Aperture elongate, narrow to slit-like. Outer apertural lip convex in its adapical portion; inner lip with four to five fine columellar folds gradually diminishing towards siphonal canal. Rachidian with four to seven cusps, with one to two marginal pairs of cusps notably weaker than the two or three medial cusps; unpaired central cusp when present equal or weaker than two flanking cusps ( Fig. 25A–H). Lateral teeth broad, with seven to 12 triangular or spindle-like, long and pointed subequal cusps, gradually increasing in size towards rachidian, with one cusp strongest, sometimes very long, greatly exceeding others, resembling a tin-opener ( Fig. 25D–F).