Satsuma luteolella, 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 : 475-477

SATSUMA LUTEOLELLA SP. NOV. ( FIGS 29 , 30 )

Material examined

Type specimen: Holotype: TMMT 0611 (from type locality, dry shell, tissue in alcohol). Total 17 paratypes: seven paratypes from type locality: TMMT 0659 (dry shell, tissue in alcohol, dissected); TMMT 0640–0641 , TMMT 0678 (dry shell, tissue in alcohol); BMNH 20060757 , ANSP 413678 , SMF 329387 (dry shell). Ten paratypes from Antong , Hualien: TMMT 0642 (juvenile, in alcohol); TMMT 0639 , TMMT 0676– 0677 (dry shell, tissue in alcohol); NMNS 005405-2 , BMNH 20060758–20060759 , ANSP 413677 (N = 2), SMF 329386 (dry shell).

Type locality

Fuyuan, Hualien County, eastern Taiwan ( Fig. 1 , Table 1) .

Diagnosis

Shell and soft body yellowish without pedal stripe; number of whorls more than six; shell highly conical, with shell height/diameter ratio = 1.5.

Etymology

L. luteola: yellow; L. -ella: diminutive suffix, referring to the small and yellowish shell.

Description

Shell ( Fig. 29 ): Dextral, thin, conical, medium sized to large. Apex obtuse. Whorls inflated. Periphery bluntly angulated, arc-like. Base inflated. Pre-apertural constriction behind peristome absent. Shell colour yellowish white. Surface even, matt, with fine axial and spiral striae. Periostracum thin. Aperture diagonal, ovate, angulated curve between outer lip and inferior lip. Peristome thin. Columellar lip vertical, reflected covering umbilicus. Umbilicus mostly closed, crevice-like.

Band or stain: Polymorphism exists in this taxon. Some individuals do not possess any colour band or stain, whilst some exhibit a red-brown umbilicus; however, the inferior lip and outer lip lack coloration. Others have a peripheral or sub-peripheral band around the whorls. Band formula = 0 0 0 0 0 0 0 0; 0 0 0 0 0 0 7 0; 1 0 0 4 0 0 7 0; 1 0 0 0 5 0 7 0; 1 (0 0 0) 5 0 7 0 (very rare).

Reproductive system ( Fig. 30 ): Bursa stalk tapering, not enlarged at base, shorter than spermoviduct. Bursa copulatrix oval to ellipsoid. Proximal vagina muscular, swollen, with 12–17 internal folds; middle vaginas of same width or more constricted, muscular; distal vagina medium in length, one-third length of vagina, same width as middle vagina, constricted towards atrium, with fine wrinkles inside. Flagellum conical, swollen at base with short and digitate tip. Penial caecum short, conical, blunt, furrowed externally; cecal pilasters two in number; remaining inner walls contain 12–14 weak ridges. Proximal penis elongated, muscular, twisted, unevenly furrowed externally, with strong folds internally; principal pilaster long, twice to threetimes length of penial caecum; middle penis constrictive, shortly elongated, with well-defined, strong and corrugated pilasters; distal penis of same strength as middle penis, containing strong, smooth pilasters inside. Spinules present in penial caecum, penis and vagina.

Distribution

The species was found in lowland broadleaf forest from Liyutan, Mataian, Fuyuan and Antong ( Fig. 1 , Table 1). It was thus considered to be distributed around the northern parts of the East Rift Valley, eastern Taiwan.

Remarks

Found from 2 to 3 m above the ground up to the canopy. Mature individuals are found in summer ( Fig. 29M, N ).

Satsuma luteolella is similar to S. pilsbryi (described below) based on morphological characters. The former differs from the latter in having larger shell size, greater number of whorls, paler shell colour, slender base of bursa stalk, long principal pilaster, less expanded proximal penis and lack of a pre-apertural constriction. A dwarf form, which has similar shell dimensions (17.5 mm height, 13.0 mm diameter) to S. pilsbryi , was found in the lowland forest around Antong area, southern Hualien County, eastern Taiwan. They can be easily distinguished based on the characters listed above.

Figures

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

Figure 29. Satsuma luteolella sp. nov. A–D, holotype (TMMT 0611, shell height = 23.5 mm). E, F, paratype (TMMT 0639, shell height = 21.9 mm). G, H, paratype (TMMT 0640, shell height = 20.5 mm). I, J, paratype (TMMT 0641, shell height = 21.7 mm). K, L, paratype (TMMT 0642, shell height = 16.3 mm). M, N, living specimens.

Figure 30. Reproductive system of Satsuma luteolella sp. nov. (paratype, TMMT 0659). A, whole genitalia; B, interior of genitalia. Scale bar = 5 mm. See text for abbreviations.