Amplirhagada camdenensis Köhler 2010, n.sp.

Amplirhagada camdenensis n.sp.

Type locality (Fig. 1). Western Australia, Kimberley, Bonaparte Archipelago, Camden Sound, Augustus Island, northwestern section, 15°20'16"S 124°31'16"E; KIS 1-49. Vine thicket amongst boulders at base of sandstone cliffs, under rocks (leg. M. Shea, 25 May 2008).

Type material. Holotype WAM S34624 (Pl. 2.12). AMS C463722 (3 preserved specimens, as holotype), WAM S37006 (5 preserved specimens, as holotype), WAM S37005 (3 preserved specimens, 15°20'59"S 124°31'30"E).

Additional, non-type material. WAM S37007 –8, WAM S37445 –50, WAM S41481, FMNH 219063 (Augustus Island).

Etymology. In reference to Camden Sound, in which Augustus Island is situated.

Sealing strategy. Free sealer.

Shell (Fig. 77A–B, Pl. 2.12). Globose, with medium to high spire; solid. Periphery evenly rounded to slightly angulate; upper sector of whorl flattened to slightly shouldered, basal sector rounded. Umbilicus forming a chink to narrowly winding opening, 40–100 percent concealed by columellar reflection. Background colour yellowish brown to horn; sub-sutural band diffuse, dark to chestnut brown, becomes more indistinct or blurs towards tip of whorl, may fuse with mid-whorl band to cover shell in light brown colour; mid-whorl band diffuse, dark to chestnut brown, thin to moderately broad, visible on last whorl(s) only; ventral colour whitish cream to yellowish brown; outer and inner lip colour differs from shell, pinkish brown. Protoconch c. 3.5 mm in diameter, comprising 2 whorls, smooth. Teleoconch smooth except of faint axial growth lines. Angle of aperture 30°; outer lip rounded, moderately thick, expanded, not or slightly reflected, basal and palatal node absent. Parietal wall of inner lip absent.

Pallial morphology. Pigmentation on mantle mottled, dark grey. Kidney extending about half of pallial cavity.

Genital morphology (Figs. 76, 78). Penis straight, shorter than anterior part of oviduct, very thin. Vas deferens forms simple loop before entering penis. Penial retractor muscle as long as penis. Penial verge rather short ( 1 ⁄ 8 – 1 ⁄ 4 of length of penial chamber), broad, with pointed to rounded tip. Penial wall pustules absent. Main stimulatory pilaster not well differentiated, narrow, smooth, on apical to median portion of penial chamber. One to three additional, smooth, narrow pilasters on apical portion. Vas deferens entering penial sheath in upper third. Vagina rather short, medially to posteriorly inflated; inner vaginal wall predominantly smooth, with few weakly developed longitudinal pilasters. Spermathecal duct moderately wide, internally smooth. Spermathecal head globular to elongately inflated, connected with oviduct by connective tissue, internally smooth, with thin wall. Free oviduct comprising about half of anterior part of oviduct; more or less straight. Spermoviduct much longer than anterior part of oviduct. Talon embedded in albumen gland at junction with spermoviduct.

Radular morphology (Fig. 77C–D). Rectangular. Tooth formula C+16+4+?. With 122 rows of teeth, 27.4 rows per mm (n = 1). Central teeth with sharply pointed, triangular mesocones, shorter than base of tooth; ectocones vestigial. Lateral teeth with sharply pointed, triangular to ovate mesocones, length equal to base of tooth; ectocones and endocones vestigial. Marginal teeth with triangular to broadly flattened mesocones; ectocones shorter and narrower than mesocones; endocones vestigial.

Comparative remarks. Material of this species has been labelled as “ Amplirhagada sp. 65” by Solem. It has the smallest of all dome-shaped shells with a significantly higher H/D ratio as most other species (Table 1). Absence of penial wall pustules and pattern of smooth, longitudinal pilasters are diagnostic.