Satsuma careocaecum, 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 : 458-460

SATSUMA CAREOCAECUM SP. NOV. ( FIGS 15 , 16 )

Material examined

Type specimen: Holotype: TMMT 0603 (from type locality, dry shell, tissue in alcohol). Seventeen paratypes: all from type locality, TMMT 0651 (dry shell, tissue in alcohol, dissected); TMMT 0622–0624 , TMMT 0646–0650 (dry shell, tissue in alcohol); BMNH 20060769–20060771 , ANSP 413686 (N = 3), SMF 329393–329394 (dry shell).

Type locality

Guanziling, Tainan County, southern Taiwan ( Fig. 1 , Table 1) .

Diagnosis

Shell and soft body white with grey pedal stripe; base expanded; penial caecum absent.

Etymology

L. careo: lack; caeca: caecum, referring to the lack of a penial caecum.

Description

Shell ( Fig. 15 ): Dextral, conical, thin, rigid, medium sized. Apex obtuse. Whorls inflated. Periphery bluntly angulated to arc-like. Base expanded. Pre-apertural constriction behind outer and inferior lips present. Surface sheen with spiral striae. Shell colour white or white milky. Periostracum fine. Aperture diagonal, ovate-lunate. Peristome thin, expanded, reflected. Inferior lip curved downwards. Columellar lip oblique, reflected covering most of umbilicus. Junction of columellar lip and inferior lip roundly angulated.

Band or stain: Polymorphism exists in this taxon. Most individuals exhibit a red-brown to black-purple stain around the umbilicus, columellar, columellar lip and apex; a sub-peripheral band is present in some specimens. The outer lip and inferior lip lack such coloration. Band formula = 0 0 0 0 0 0 0 0; 1 0 0 0 0 0 7 0; 1 0 0 0 5 0 0 0; 1 0 0 0 5 0 7 0.

Reproductive system ( Fig. 16 ): Bursa stalk long, almost slender. Proximal and middle vagina equally thin without conspicuous boundary between them, smooth externally, bearing 8–12 smooth, irregular strength folds internally; distal vagina one-third length of vagina. Flagellum long, tapering, with slender tip. Epiphallus with four weak pilasters inside. Penial caecum absent. Segment corresponding to penial caecum with three weak pilasters inside; then continued by slender tubule to penis. No verge or apparent internal constriction observed. Penis weak, gradually becoming robust towards atrium; middle penis with five clear, smooth, thin pilasters; distal penis with five strong, irregular, wiggly pilasters. Spermatophore ( Fig. 16C ) found in bursa stalk of figured individual ( TMMT 0651); apical end partly digested in bursa copulatrix (not shown); tail tip remains in proximal vagina; cross-section at middle part ( Fig. 16D ) with three shallow valleculae and a projected fold. Six specimens were dissected.

Distribution

From Guanziling to Dongshan, northern Tainan County, southern Taiwan ( Fig. 1 , Table 1).

Remarks

The perching distance is typically from 3 m above ground to the canopy. Mature individuals often appear during winter ( Fig. 15K ).

The absence of a penial caecum is the most distinct character among species of this species complex. Some Satsuma species , e.g. S. nux paiwanis ( Kuroda, 1941) , showed a reduced penial caecum ( Chang, 1989), whilst others, e.g. Pancala batanica pancala ( Schmacker & Boettger, 1891) and Pancala bacca ( Pfeiffer, 1866 [1865]), showed a lack of a penial caecum with an apparent verge at insertion of the epiphallus ( Chang, 1992; Hwang, 1995). A totally degenerated penial caecum as seen in S. careocaecum sp. nov. was not recorded in Satsuma .

The species differs from S. lini in having a greater number of whorls, apical spot, sub-peripheral band and umbilicus spot; from S. hagiomontis sp. nov. and S. swinhoei sp. nov. in having bluntly angulated periphery; and from S. insignis in having thinner shell and regularly expanded body whorl.

Figures

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

Figure 15. Satsuma careocaecum sp. nov. A–D, holotype (TMMT 0603, shell height = 19.1 mm). E, F, paratype (TMMT 0622, shell height = 17.8 mm). G, H, paratype (TMMT 0623, shell height = 17.9 mm). I, J, paratype (TMMT 0624, shell height = 17.7 mm). K, living specimen. Arrow indicates the pre-apertural constriction.

Figure 16. Reproductive system of Satsuma careocaecum sp. nov. (paratype, TMMT 0651). A, whole genitalia; B, interior of genitalia. C, part of spermatophore showing its position in the female genitalia. D, cross-section of spermatophore at dash line. Scale bar for A–C = 5 mm, for D = 0.5 mm. See text for abbreviations. An abbreviation with a question mark indicates a tentative portion of genitalia.