Amplirhagada angustocauda, 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 : 192-193

Amplirhagada angustocauda n.sp.

Type locality. Western Australia, NW Kimberley, SE of Prince Frederick Harbour, 10.5 km E of Mt. Brookes, 6.5 km from coast; west bank tributary Roe River ; 15°12'45"S 125°29'30"E ( RFS 16-1 ; coll. V. Kessner, 16 Jun 1987) ( Fig. 1 ) .

Type material. Holotype WAM S34743 (preserved specimen, dissected) . Paratypes FMNH 220650 (preserved specimen) (Pl. 1.14) , WAM S34744 (2 dried shells) , FMNH 220654 (dried shell) .

Etymology. The species epithet is derived from “angustus” (Latin = narrow) and “cauda” (Latin = penis), in reference to the narrow and elongate epiphallus being a characteristic of this species.

Description

Shell (Pl. 1.14; Fig. 40 A–C ). Broadly conical with moderately elevated spire. Thin, translucent. Periphery sharply angulate; upper and basal sectors rounded. Umbilicus 30% concealed by columellar reflection. Background colour yellowish brown; spiral bands absent; outer and inner lip colour whitish. Protoconch 3.4 mm in diameter, comprising about 1.5 whorls, essentially smooth. Teleoconch with welldeveloped, irregular axial growth lines; evenly distributed across shell surface. Angle of aperture c. 60°; outer lip sharp, well rounded, slightly expanded; basal node absent. Parietal wall of inner lip absent. Average shell size 11.7±1.2 × 15.7± 0.7 mm ( Table 1).

Radular and jaw morphology ( Fig. 40 D–F ). Tooth formula C + 10–13 + 4 + 16, with 120 rows of teeth 130 (n = 1). Jaw with 11 plates.

Genital morphology ( Figs 41–42 ). Penis straight, with a short, tubular, very thin penis proper; lumen of penial chamber short extending only about 1/3 to 1/4 of length of penial complex. Inner penial wall with few smooth longitudinal pilasters; no main stimulatory pilaster differentiated. Penial sheath distally thick, proximally thin. Penial retractor muscle stubby, no longer than 1/5 of penial complex. Vas deferens moderately thick, entering penial sheath at about half of length of penial complex, forming an extended loop, reflecting as an elongate, thin, tubular epiphallus, which gives rise to the short penis. Inner wall of epiphallus smooth, ciliated. Penial verge tiny, slender, with pointed tip. Vagina moderately long, proximally slightly inflated; inner vaginal wall and wall of bursa copulatrix with smooth longitudinal pilasters. Bursa copulatrix slightly extending base of spermoviduct. Free oviduct comprising about half of length of anterior part of oviduct. Spermoviduct longer than anterior part of oviduct.

Aestivation strategy. Unknown.

Remarks. Description is based on dissection of the holotype. The species was listed by Solem (1991) as “ Amplirhagada NSP 33”. Shell smaller than in most other congeners.Various features of the penial anatomy are very characteristic: vas deferens reflecting as a narrow, elongated epiphallus, the penial chamber is very short supporting longitudinal pilasters but no pustules. Species differs by its markedly different penial anatomy from A. wilsoni Solem, 1981 , which also occurs at the banks of the Roe River not too far from the type locality of this species. For comparison with A. moraniana having also a similar shell see remarks under this species.

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 40. Amplirhagada angustocauda n.sp. SEM of shell, radula and jaw (WAM S34743). (A) Protoconch and first teleoconch whorls viewed from above. (B) Detail of first teleoconch whorls viewed from above. (C) Close-up of sculpture on last whorl, lateral view. (D) Jaw. (E) Central and inner lateral teeth viewed from above. (F) Marginal teeth viewed from above. Scale bars: A, 200 µm; B–C, 1 mm D, 100 µm; E, 20 µm; F, 10 µm.

Figure 41. Genitalia of Amplirhagada angustocauda n.sp. (WAM S34743). For labelling of structures see Fig. 3. Scale bar = 5 mm.

Figure 42. Penial anatomy of Amplirhagada angustocauda n.sp. (WAM S34743). For labelling of structures see Fig. 4. (A) Interior anatomy of the penial wall. (B) Schematic view of the penis with the penial sheath being removed. Scale bars = 3 mm.