Satsuma pilsbryi, Wu & Hwang & Lin, 2008

Wu, Shu-Ping, Hwang, Chung-Chi & Lin, Yao-Sung, 2008, Systematic revision of the arboreal snail Satsuma albida species complex (Mollusca: Camaenidae) with descriptions of 14 new species from Taiwan, Zoological Journal of the Linnean Society 154 (3), pp. 437-493 : 484-486

SATSUMA PILSBRYI SP. NOV. ( FIGS 37 , 38 )

Material examined

Type specimen: Holotype: TMMT 0614 (from type locality, dry shell, tissue in alcohol, dissected). Nine paratypes: all from type locality, TMMT 0644 , TMMT 0665–0670 (dry shell, tissue in alcohol); BMNH 20060766 , ANSP 413684 (dry shell).

Type locality

Taiyuan, Taitung County, eastern Taiwan ( Fig. 1 , Table 1) .

Diagnosis

Shell and soft body yellowish without pedal stripe; shell conical with small diameter; pre-apertural constriction present behind outer lip; base of bursa stalk conical; principal pilaster short; proximal penis short, swollen.

Etymology

This species is named after the American malacologist Henry A. Pilsbry (1862–1957) who described two species of this group.

Description

Shell ( Fig. 37 ): Dextral, conical, thin, medium sized to small. Apex obtuse. Whorls inflated. Periphery bluntly angulated, arc-like. Base expanded. Preapertural constriction behind outer lip only. Shell colour light yellow. Periostracum thin. Surface evenly smooth, with fine axial and spiral striae. Aperture diagonal, ovate. Junction between outer lip and inferior lip an angulated curve. Peristome thin, expanded at inferior lip and outer lip. Inferior lip curved downward. Columellar lip vertical, reflected. Umbilicus mostly covered by columellar lip, crevice-like. Junction between columellar lip and inferior lip obtusely angulated.

Band or stain: Polymorphism exists in this taxon. Some individuals lack colour band and stain, whilst some exhibit light red-brown apical spot, subperipheral band or umbilicus stain. Inferior and outer lips are colourless. Band formula = 0 0 0 0 0 0 0 0; 10005070.

Reproductive system ( Fig. 38 ): Bursa stalk short, fourfifths spermoviduct, tapering, swollen at base. Bursa copulatrix clavated. Proximal vagina muscular, swollen, smooth, with 14 pilasters internally; middle vagina short, constricted, thick-walled, with 17 weak and wiggly folds inside; distal vagina long, nearly one-third length of vagina, gradually constricted towards atrium, with low folds or fine wrinkles inside. Flagellum short and swollen at base, with apparently short and quickly tapering tip. Epiphallus short, with four pilasters inside. Penial caecum moderate, conical, blunt, smooth; cecal pilaster two in number; remaining inner walls of penial caecum contain several moderate ridges. Proximal penis short, swollen, smooth externally, with one deep groove on epiphallic side corresponding to principal pilaster internally; principal pilaster same length as penial caecum; middle penis constricted suddenly, regularly elongated, smooth externally, with seven to nine strong and smooth pilasters; distal penis short, only weak folds or fine wrinkles inside. Spinules present in vagina, penial caecum and proximal penis. Two individuals from the type locality were dissected.

Distribution

This species was found in lowland forest habitats around the Taiyuan valley, Taitung County, eastern Taiwan ( Fig. 1 , Table 1).

Remarks

The perching distance from ground is 2 m; also active on low shrubbery. Adults were found in summer ( Fig. 37G ).

The shell morphology of this species is similar to that of S. vallis , but is differs in dimensions and shell colour. The genital morphology of this species is fundamentally similar to that of S. viridibasis and S. vallis with the following exceptions: (1) the proximal vagina is stronger, (2) the base of the bursa stalk is conical and (3) the penial caecum and proximal penis are strong, smooth and muscular. Satsuma pilsbryi is probably an intraspecific variation from southern populations of S. vallis and S. viridibasis in shell morphology. However, the well-defined geographical isolation and distinguishable reproductive system reveal it merits specific status.

Figures

Figure 1. Sampling localities of all taxa in Taiwan. Bold line, Central Range; thin line, administrative boundary.

Figure 37. Satsuma pilsbryi sp. nov. A–D, holotype (TMMT 0614, shell height = 17.9 mm). E, F, paratype (TMMT 0644, shell height = 17.6 mm). G, living specimen. Arrow indicates the pre-apertural constriction.

Figure 38. Reproductive system of Satsuma pilsbryi sp. nov. (holotype, TMMT 0614). A, whole genitalia; B, interior of genitalia. Scale bar = 5 mm. See text for abbreviations.