Amplirhagada dubitabile, Köhler, 2010

Köhler, Frank, 2010, Uncovering Local Endemism in the Kimberley, Western Australia: Description of New Species of the Genus Amplirhagada Iredale, 1933 (Pulmonata: Camaenidae), Records of the Australian Museum 62 (2), pp. 217-284 : 271-273

Amplirhagada dubitabile n.sp.

Type locality ( Fig. 1 ). Western Australia, Kimberley, Bonaparte Archipelago, Doubtful Bay , Steep Island , 2.3 km NE of Raft Point, 16°03'36"S 124°22'03"E; KC-002 (leg. V. Kessner & A. Longbottom, 08 July 1988) .

Type material. Holotype WAM S34627 (Pl. 2.15) . Paratypes AMS C463762 (3 preserved specimens), FMNH 219047 (8 preserved specimens), WAM S41478 (5 preserved specimens) .

Etymology. From dubitabile (Latin = doubtful), in reference to Doubtful Bay, where this species occurs on Steep Island.

Shell ( Fig. 85A–C , Pl. 2.15). Semi-globose to broadly conical, with medium high spire; solid. Periphery slightly angulate; upper and basal sectors of whorls rounded. Umbilicus open, forming narrowly winding opening, 30–70 percent concealed by columellar reflection. Background colour brownish beige, may display irregular pattern of hornish growth lines; sub-sutural band absent; mid-whorl band absent or diffuse, yellowish brown, thin, visible on last whorl only; ventral colour horn; outer lip colour differs from shell, horn; inner lip whitish. Protoconch c. 2.8 mm in diameter, comprising 2 whorls, smooth. Teleoconch with pronounced axial growth lines. Angle of aperture 45°; outer lip rounded, moderately thick, slightly expanded, not or slightly reflected, basal and palatal node absent. Parietal wall of inner lip inconspicuous.

Vagina rather short, posteriorly inflated; inner vaginal wall with weakly developed longitudinal pilasters. Spermatheca slightly extending over base of spermoviduct. Spermathecal duct wide, internally with smooth longitudinal pilasters. Spermathecal head globular, connected with oviduct by connective tissue, internally smooth, with delicate wall. Free oviduct comprising about half of anterior part of oviduct, more or less straight. Spermoviduct longer than anterior part of oviduct. Talon embedded in albumen gland close to anterior end of albumen gland.

Pallial morphology. Pallial cavity short, extending half a whorl; mantle pigmentation mottled, greyish black. Kidney extending about half of pallial cavity.

Genital morphology ( Figs. 86–87 ). Penis straight, more or less of same length as anterior part of oviduct. Vas deferens coils once before entering penis. Penial retractor muscle shorter than penis. Penial verge short (<1 ⁄ 8 penial chamber), broad, pointed. Penial wall pustules absent; wall covered by delicate, narrow, longitudinal pilasters. Main stimulatory pilaster well-differentiated; smooth undulating, well developed at apical portion, decreasing in size in median portion, largely reduced at basal portion of penial chamber. Vas deferens entering penial sheath in upper third. Radular morphology ( Fig. 85E–F ). Rectangular. Tooth formula C+16+3+22. With 139 rows of teeth, 32.3 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 small; endocones vestigial. Marginal teeth with elongate to triangular mesocones; ectocones shorter and narrower than mesocones; endocones smaller than ectocones.

Comparative remarks. Material of this species has been labelled as “ Amplirhagada sp. 63” by Solem. Shell similar to A. kimberleyana and A. gemina in shape, size, and colouration. Inner penial wall structure (lamellae, no pustules with long, undulating main pilaster) very characteristic.

Figures

Figure 1. Distribution of Amplirhagada species in the Kimberley region, northwestern Australia. (1) A. euroa n.sp., Adolphus Island. (2) A. solemiana n.sp., Middle Osborn Island. (3) A. indistincta n.sp., Southwest Osborn Island, Kidney Island. (4) A. combeana, Cassini Island. (5) A. mckenziei n.sp., Oliver Island. (6) A. ponderi n.sp., Kingsmill Island. (7) A. montesquieuana n.sp., Fenelon Island. (8) A. descartesana n.sp., Descartes Island. (9) A. katerana, Katers Island. (10) A. puescheli n.sp., unnamed island near Prudhoe Island. (11) A. decora n.sp., A. kessneri n.sp., Bigge Island. (12) A. berthierana n.sp., Berthier Island. (13) A. lamarckiana n.sp., Lamarck Island.(14) A. anderdonensis n.sp., unnamed island, Anderdon Islands. (15) A. tricenaria n.sp., Prince Frederick Harbour, north of Hunter River mouth. (16) A. regia n.sp., A. boongareensis n.sp., A. gibsoni n.sp., and Amplirhagada sp., Boongaree Island. (17) A. yorkensis n.sp., Coronation Island. (18) A. buffonensis n.sp., Buffon Island. (19) A. uwinsensis n.sp., Uwins Island. (20) A. sphaeroidea n.sp., St. Andrews Island. (21) A. basilica n.sp., and A. camdenensis n.sp., Augustus Island. (22) A. kimberleyana n.sp., NW of Wilson Point. (23) A. gemina n.sp., 1.5 km SE of Hall Point. (24) A. dubitabile n.sp., Steep Island. (25) A. napierana, north Napier ranges. (26) A. percita, Napier ranges. (27) A. castra, A. mitchelliana, and A. varia, Mitchell Plateau.

Figure 85. SEM photographs of shell, jaw and radula of Amplirhagada dubitabile n.sp., paratype FMNH 219047:(A) apical whorl viewed from above (scale 200 µm); (B) sculpture on penultimate whorl viewed rectangular from above (scale 200 µm); (C) close-up showing growth lines on last whorl (scale 200 µm); (D) jaw (scale 100 µm); (E) central and inner lateral teeth (scale 20 µm); (F) outer lateral and inner marginal teeth (scale 20 µm).

Figure 86. Genitalia of Amplirhagada dubitabile n.sp., paratype FMNH 219047 (8 July, scale 10 mm). Compare with Fig. 3 for labelling of structures.

Figure 87. Interior of penial chamber of Amplirhagada dubitabile n.sp., paratype FMNH 219047 (8 July, scale 3 mm). Compare with Fig. 4 for labelling of structures.