Amplirhagada discoidea, Köhler, 2011

Köhler, Frank, 2011, Descriptions of New Species of the Diverse and Endemic Land Snail Amplirhagada Iredale, 1933 from Rainforest Patches across the Kimberley, Western Australia (Pulmonata: Camaenidae), Records of the Australian Museum 63 (2), pp. 167-202 : 181

Amplirhagada discoidea n.sp.

Type locality. Western Australia, NW Kimberley mainland, Scott Strait, 8.3 km E of Savage Hill on Bigge Island ; 14°37'15"S 125°15'15"E ( RFS 05-2 ; coll. V. Kessner, 5 Jun 1987) ( Fig. 1 ) .

Type material. Holotype WAM S34722 (preserved specimen) (Pl. 1.7; Table 1) . Paratypes AM C.472927 (3 preserved specimens), WAM S34723 (5 preserved specimens) , FMNH 220064 (8 preserved specimens) , AM C.472928 (6 dried shells), WAM S34724 (12 dried shells) , FMNH 220063 (20 dried shells) .

Etymology. In reference to discoidal shape of shell.

Description

Shell (Pl. 1.7; Fig. 21A–D ). Broadly conical with low spire, discoid. Rather thin but solid, slightly translucent. Periphery angulate; upper and basal sectors slightly flattened. Umbilicus 10–20% concealed by columellar reflection. Background colour light yellowish brown; peripheral band conspicuous, well developed, moderately broad, clearly visible on last whorl only; sub-sutural band broad, well developed, brown, visible on last whorl only; both bands may blend into each other covering shell with a dark brown tone; outer and inner lip colour white, conspicuously contrasting shell colour. Protoconch 3.1 mm in diameter, comprising about one whorl, with inconspicuous radially elongated pustulations. Teleoconch almost smooth, with very faint, regular axial growth lines. Angle of aperture about 45 degrees; outer lip thin, well rounded, slightly expanded, not or slightly reflected; basal node. Parietal wall of inner lip thin. Average shell size 12.4±0.7 × 20.9± 0.9 mm ( Table 1).

Radular and jaw morphology ( Fig. 21 E–G ). Tooth formula C + 13–15 + 4 + 16–22, with 120 rows of teeth (n = 2). Jaw with c. 10 plates.

Genital morphology ( Figs 20 , 22 ). Penis rather straight, tubular, about as long as anterior part of oviduct. Penial sheath very delicate, distally thicker. Length of penial retractor muscle equivalent to about 1/3 of length of penial complex. Penial verge elongately conical, with blunt tip, short, extending about ¼ of length of penial chamber. Inner penial wall entirely covered by densely arranged, very small pustules. Several more or less developed longitudinal

Figures

Figure 1. Distribution of Amplirhagada species described in the present work. (A) A. atlantis n.sp. (B) A. carsoniana n.sp. (C) A. alicunda n.sp. (D) A. davidsoniana n.sp. (E) A. vialae n.sp. and A. discoidea n.sp. (F) A. forrestiana n.sp. (G) A. inusitata n.sp. and A. epiphallica n.sp. (H) A. lindsayae n.sp. (I) A. angustocauda n.sp. (K) A. moraniana n.sp. (L) A. gardneriana n.sp. (M) A. bendraytoni n.sp. (N) A. coffea n.sp. (P) A. carinata Solem, 1981. When species occur at more than one locality, the type locality of newly described taxa is marked with an asterisk.

Figure 20. Genitalia of Amplirhagada discoidea n.sp. (AM C.472927).For labelling of structuressee Fig.3. Scalebar = 10 mm.

Figure 21. Amplirhagada discoidea n.sp. SEM of shell (AM C.472928), radula and jaw (AM C.472927).(A) Protoconchand first teleoconch whorls viewed from above.(B) Detail of first teleoconch whorls viewed from above. (C) Close-up of last whorl from above. (D) Lateral view of last whorl.(E) Jaw. (F) Central and inner lateral teeth viewed from above. (G) Marginal teeth viewed from above. Scale bars: A, C–D, 1 mm; B, 200 µm; E, 100 µm; F–G, 10 µm.

Figure 22. Penial anatomy of Amplirhagada discoidea n.sp. (AM C.472927).For labelling of structures see Fig.4. Scale bar = 5 mm. Scale bar (inset) = 0.25 mm.