Satsuma hagiomontis, 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 : 447-449

SATSUMA HAGIOMONTIS SP. NOV. ( FIGS 5 , 6 )

Material examined

Type specimen: Holotype: TMMT 0604 (from type locality, dry shell, tissue in alcohol). Five paratypes: all from type locality, TMMT 0615 (dry shell, tissue in alcohol, dissected); TMMT 0616 (dry shell, tissue in alcohol); BMNH 20060751 , BMNH 20060752 , ANSP 413674 (dry shell).

Additional material: Museum of Zoology, National Taiwan University ( NTUM): two dry shells, collected from Kuwarusu (= Taiwu, Pingtung County, southern Taiwan ) in 1918 .

Type locality

M. Beidawushan, Pingtung County, southern Taiwan ( Fig. 1 , Table 1) .

Diagnosis

Shell and soft body white with grey pedal stripe; periphery keeled; shell height/diameter ratio close to 1.0; distal vagina short; penis corrugated on surface; penial caecum conical; genitalia with or without spinules.

Etymology

L. hagio: holy, L. montis: mountain. The type locality, Mt Beidawushan, is a holy mountain of two aboriginal tribes, the Paiwan and Rukai.

Description

Shell ( Fig. 5 ): dextral, conical, thin, fragile, semitranslucent, medium sized. Apex obtuse. Whorls inflated. Peripheries bluntly angulated with keel extended to peristome. Base inflated. Pre-apertural constriction behind outer and inferior lips present. Shell surface smooth, glossy, with spiral striae. Shell colour white milky with thin periostracum. Aperture diagonal, ovate-lunate. Peristome thin, expanded, reflected at curved inferior lip. Superior columellar lip vertical, reflected, covering most of umbilicus. Inferior columellar lip oblique, continual to inferior lip.

Band or stain: Polymorphism exists in this taxon. Some individuals exhibit a red-brown to black-purple stain around the umbilicus, columellar, columellar lip, inferior lip and apex, others have spiral colour band around the whorls or at the base. The outer lip exhibits no coloration. Band formula = 1 0 0 0 0 0 7 8; 1 0 0 0 5 0 7 0; 1 0 0 4 0 0 7 0; 1 0 0 4 0 0 7 8.

Reproductive system ( Fig. 6 ): Bursa stalk long, with apparently expanded and conical base, regularly tapering towards oval bursa copulatrix. Proximal vagina muscular, swollen, smooth externally, with 14–17 strong, smooth folds internally. Middle vagina less muscular, distinctly constrictive, twisted. Distal vagina short, one-quarter of vagina in length. Flagellum long, tapering, not swollen at base. Pilaster in epiphallus wide, weak, three in number. Penial caecum long, depressed-conical. Cecal pilaster two in number, moderately weak, not strongly corrugated on surfaces. Principal pilaster and proximal penis absent. Middle penis long, twisted, depressed, with seven to nine moderately strong, wiggly, corrugated pilasters inside. Distal penis short, constrictive, with three wide and low pilasters vanishing towards atrium internally. Of the two dissected specimens one ( TMMT 0615) has many spinules on the surface of the pilasters in the middle penis.

Distribution

The species was found only in a narrow area of mid-altitude (1000–1400 m) forest near Mt Beidawushan , Pingtung County, southern Taiwan ( Fig. 1 , Table 1) .

Remarks

These arboreal herbivores are nocturnal, perching under leaves more than 2 m above ground. Adults were found during summer ( Fig. 5I, J ). The species differs from S. albida in having a keeled periphery, lower spire with shell height/diameter ratio close to 1.0, short distal vagina; corrugated penis externally, conical penial caecum and spinules inside genitalia. The conical penial caecum and strongly corrugated penis are unique among white-shelled species in west Taiwan.

Figures

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

Figure 5. Satsuma hagiomontis sp. nov. A–D, holotype (TMMT 0604, shell height = 17.7 mm). E, F, paratype (TMMT 0615, shell height = 14 mm). G, H, paratype (TMMT 0616, shell height = 14 mm). I, J, living specimens. Arrow indicates the pre-apertural constriction.

Figure 6. Reproductive system of Satsuma hagiomontis sp. nov. (paratype, TMMT 0615). A, whole genitalia; B, interior of genitalia. Scale bar = 5 mm. See text for abbreviations.