Amplirhagada yorkensis, 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 : 257-259

Amplirhagada yorkensis n.sp.

Careening Bay ; 15°06'41"S 125°01'53"E; KC-040), WAM S37376 –8 , WAM S36980 –6 , WAM S37394 –404 , AMS C463712–4 (Coronation Island, southern section) .

Etymology. In reference to York Sound, where this species occurs on islands and likely adjacent mainland.

Sealing strategy. Free sealer.

Shell ( Fig. 62A–B , Pl. 2.4–5). Broadly conical to almost flat with low spire; thin (translucent). Periphery evenly rounded to slightly angulate; upper and basal sectors of whorls rounded. Umbilicus open, narrowly winding, 30–90 percent concealed by columellar reflection. Background and ventral colour brownish horn; sub-sutural band absent; mid-whorl band absent or diffuse, light yellowish brown, thin, generally not very pronounced, only visible on last whorl(s); outer lip colour same as shell; inner lip translucent, whitish. Protoconch c. 2.7 mm in diameter, comprising 2 whorls, with fine, indistinct axial lirae. Teleoconch smooth except of axial growth lines. Angle of aperture 30°; outer lip rounded, sharp, expanded to largely expanded, reflected; basal and palatal node absent. Parietal wall of inner lip inconspicuous. Type locality ( Fig. 1 ). Western Australia, northwestern Kimberley , Bonaparte Archipelago , York Sound , Coronation Island , southern section, 15°01'52"S 124°56'56"E; KIS- 3–085. Vine thicket on upper slopes of a volcanic hill behind mangroves, under rocks (leg. V. Kessner, 30 May 2008) .

Type material. Holotype WAM S34619 (Pl. 2.4) . Paratypes AMS C463711 (24 preserved specimens), WAM S36979 (42 preserved specimens) .

Additional, non-type material. WAM S41477 , FMNH 219151 (12 preserved specimens, Port Nelson, 5 km N of Mt. Knight, c. 3 km E of

Pallial morphology. Pallial cavity moderately deep, extending 3 ⁄ 4 whorl; mantle pigmentation spotted, black. Kidney extending about half of pallial cavity.

Genital morphology ( Figs. 61 , 63 ). Penis curved to sharply bent, more or less of same length as anterior part of oviduct. Vas deferens coils once before entering penis. Penial retractor muscle very short, stubby. Penial verge very short, slender to spatulate, with pointed tip. Penial wall pustules of average size, arranged in rows over entire length of inner penial wall. Main stimulatory pilaster well-differentiated, large, cone-shaped, sculptured by horizontal ridges that support little hooks, comprising about 3 ⁄ 4 of length of penial chamber. Vas deferens entering penial sheath in upper third. Vagina moderately wide, posteriorly inflated; inner vaginal wall with smooth longitudinal pilasters. Spermathecal duct wide, internally with smooth longitudinal pilasters. Spermathecal head pyriform, connected with oviduct by connective tissue, internally smooth with thing 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 at junction with spermoviduct. Radular morphology ( Fig. 62D–F ). Rectangular. Tooth formula C+13–14+3+18. In average with 122±1.5 rows of teeth, 32.4±2.0 rows per mm (n = 2). Central teeth with sharply pointed, triangular mesocones, shorter than base of tooth; ectocones vestigial. Lateral teeth with bluntly pointed, triangular to ovate mesocones, length equal to base of tooth; ectocones and endocones vestigial. Marginal teeth with triangular to elongate mesocones; ectocones shorter and narrower than mesocones; endocones reduced in size.

Comparative remarks. The shell is low spired with a rounded periphery and light colouration; penis with a comparatively large main pilaster. This species was referred to as “ Amplirhagada sp. 34” by Solem (1991).

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 61. Genitalia of Amplirhagada yorkensis n.sp., paratype AMS C463711 (30 May, scale 5 mm). Compare with Fig. 3 for labelling of structures.

Figure 62. SEM photographs of shell, jaw and radula of Amplirhagada yorkensis n.sp., paratype AMS C463711: (A) apical whorl viewed from above (scale 200 µm); (B) sculpture on second to forth whorl viewed from above (scale 200 µm); (C) jaw (scale 100 µm); (D) close-up of central and inner lateral teeth (scale 10 µm); (E) outer lateral and inner marginal teeth (scale 10 µm); (F) close-up of middle marginal teeth (scale 10 µm).

Figure 63. Interior of penial chamber of Amplirhagada yorkensis n.sp., paratype AMS C463711 (30 May, scale 3 mm). Compare with Fig. 4 for labelling of structures.