AMPLIRHAGADA IMPERIALIS SP. NOV.

FIGURES 21A, 22, 23

Type locality: Western Australia, Kimberley, Bonaparte Archipelago, southern section of Boongaree Island, 15°05′55.8″S, 125°10′27.4″E .

Material examined (Table 1): Holotype WAM S42948 (dissected specimen) . Paratypes WAM S42949 (two preserved specimens, Fig. 21A), AM C.470993 (two preserved bodies) (Table 1) .

Etymology: For ‘imperialis’ (Latin: ‘of the empire or emperor’), in reference to King Bungaree, name patron of Boongaree Island; adjective of feminine gender.

Description: Shell (Fig. 21A) beehive-shaped, highly turreted with angulated periphery, flattened whorls, shallow suture (H = 18.2 ± 0.6, D = 20.5 ± 0.8, W = 5.4 ± 0.05, average ± SD of three shells); background and ventral whitish crème, with diffuse brown, subsutural and mid-whorl bands, usually blending into each other covering shell in brownish suffusion; outer lip light purplish; teleoconch with regular axial growth lines. Umbilicus completely concealed by columellar reflection. Aperture simple, slightly expanded, slightly reflected, with weak basal node. Genital anatomy (Figs 22, 23). Penis inflated, long, straight; vas deferens entering penial sheath apically, penial retractor muscle moderate in length; penial verge short (<1/6 length of penial chamber), elongated; inner penial wall with large, conical, corrugated main pilaster, comprising entire length of penial wall, broadest at posterior end, tapering in thickness and development anteriorly, one or two additional pilasters of similar structure forming along entire length of inner penial wall being reduced in prominence in thickness; inner penial wall entirely covered by flat, indistinct, partly fused pustules. Vagina long (about same length as penis), tubular; bursa copulatrix moderately long, tubular, extending to anterior end of spermoviduct, with inflated head.

Comparative remarks: From all species described herein, A. imperialis clearly differs in its beehiveshaped, highly turreted shell. Three congeneric species have been described from the same island, of which A. boongareensis is most similar (Fig. 21B). However, it is even larger and more strongly elevated, having more strongly developed growth lines. Amplirhagada boongareensis differs most conspicuously in its inner penial wall sculpture, consisting of densely packed, small pustules that cover the entire surface of the penial wall as well as having a huge main pilaster. The present species may be conspecific with unidentified shells from the central section of Boongaree Island reported by Köhler (2010a) as Amplirhagada sp., in which case all known species on this island occurred in sympatry.

Distribution: Boongaree Island only (Fig. 6).