Satsuma stenozona (Moellendorff, 1884)

Zhou, Wei-Chuan, Xiao, Qiong, Chen, De-Niu & Hwang, Chung-Chi, 2011, Plectotropis yonganensis sp. nov. (Gastropoda: Bradybaenidae) from China, with revision of two Chinese camaenid species (Gastropoda: Camaenidae), Zootaxa 2929, pp. 51-56 : 52

Satsuma stenozona (Moellendorff, 1884)

( Fig. 1 , B–E; Fig. 2 , A)

Helix stenozona Moellendorff, 1884: 385 , pl. 9, fig. 5–6.

Euhadra stenozona, Pilsbry, 1890: 119 , pl. 27, figs. 4–5; Pilsbry, 1895: 214. Bradybaena stenozona, Yen, 1939: 132 , pl. 13, fig. 53.

Bradybaena (Bradybaena) stenozona, Wu, 1999: 99 –100, figs. 6.52–14, pl. 11B; Chen, 2004:140 –142, fig. 105.

Type locality. Fuzhou (26°5ʹN, 119°18ʹE), China.

Material examined. Lectotype ( SMF 8833: designated by Yen, 1939) and paralectotype ( SMF 8832); 18 in the National Forest Park of Fuzhou (May 6, 2007, 26°9ʹ50.36ʺN, 119°16ʹ54.96ʺE; FJIQBC 18220 – 18237); 8 in the Drum Mountain of Fuzhou (Oct. 16, 2010, 26°3ʹ26.18ʺN, 119°24ʹ2.38ʺE; FJIQBC 18238 – 18245); 5 in YuHua Hole of Jiangle, Fujian (Jun 1, 2007, 26°41ʹ58.90ʺN, 117°30ʹ55.02ʺ; FJIQBC 18146 – 18250); 5 in Sangu View Spot of Wuyi Mountain, Fujian (Oct. 12, 2010, 27°39ʹ2.32ʺN, 117°58ʹ1.37ʺE; FJIQBC 18251 – 18255).

Shell. Sized medium, 14.5 mm in height, 21.0 mm in width, thin but solid, low conical, glossy, straw colored. Whorls 5 1/2. Apex obtuse. Spire low conical, increased slowly, slightly convex. Body whorl expanded fast, convex. Suture deep. Red brown band seen on periphery; sometimes on apex, columellar lip. Periphery bluntly angulated. Whorls slightly descended in front, compressed on the bottom, with weakly angulated margin of umbilicus. Surface of shell with oblique, curved growth lines staggered with delicately spiral lines. Aperture diagonal and round-lunate. Peristome white, slightly expanded and reflected. Umbilicus small, open, not covered by reflected lip.

Reproductive system. Penis slender, muscular, with a moderately long penial caecum about as strong as penis. Epiphallus the same width as penis, half length with penis. Flagellum short, about 1/5 of epiphallus. Penis retractor muscle thin and long. Vas deferens slender, short. Oviduct medium in length, lightly inflated, extended from the end of vagina. Vagina to the base of pedunculus of bursa copulatrix inflated, fusiform. Pedunculus expanded at base, gradually slender towards bursa copulatrix. Bursa copulatrix oval.

Habitat. The collected site Yuhua Hole of Jiangle is Karst landform, and others are Danxia landform or acidity red earth. We usually found that snails hide under the fallen branches and leaves on ground in forests. They actively crawl on trucks or the back of large leaves with long foot during rainy seasons. Population density was not high in these collected locations. Snails of the species were first observed on early April in Fuzhou, thriven during summer, inactive on the end of October on the earth and overwintered in the form of juvenile and probably ovum.

Remark. This species has been considered as Bradybaena for a long time. Zilch (1966) examined the type specimens and considered that this is a Ganesella species closely related to G. mellea (Pfeiffer, 1866) (= Satsuma mellea ) in northern Taiwan. However, his classification has not been accepted by Chinese researchers ( Wu 1999; Chen 2004). The present research shows that the morphology of shell and reproductive system of the species are closely related to Satsuma , hence, its generic position was changed accordingly. The two species, S. mellea and Camaena (Miyakoia) sakishimana (Kuroda, 1960) in Miyako Island, are geographically and morphologically allied to S. stenozona . The latter species is characterized in the slender and long penis without a penial caecum (penial appendix) ( Minato 1980). Satsuma mellea differs to S. stenozona in having a carinate periphery, curling and thick flagellum ( Chang 1981).

Figures

FIGURE 1. Map of sampling sites and photographs of shells. A, Sampling sites of Fujian and Zhejiang, China. Square—type locality for Plectotropis yonganensis sp. nov.; Circles—sites with Satsuma stenozona; Triangles—sites with Plectotropis brevibarbis; B – E, Photographs of Satsuma stenozona from the National Forest Park of Fuzhou, China. B, C, D, (FJIQBC 18220), E (FJIQBC 18237); F – I, Photographs of Plectotropis brevibarbis. F, H, I, (FJIQBC 18256) from Tianmu Mountain, Zhejiang, China. G, (FJIQBC 18271) from Sanmen of Zhejiang, China, showing peripherical hairs; J – M, Photographs of Plectotropis yonganensis sp. nov. from Stone Forest, Yongan, Fujian China. J, L, M (FJIQBC 181201) holotype, K, (FJIQBC 181205) paratype, showing peripherical hairs.

FIGURE 2. Reproductive system. A, Satsuma stenozona from Drum Mountain, Fuzhou, China (FJIQBC 18245); B, Plectotropis brevibarbis from Tianmu Mountain, Zhejiang, China (FJIQBC 18226); C. Plectotropis yonganensis sp. nov. from Stone Forest, Yongan, Fujian China (FJIQBC 181219). AG: albumen gland; E: epiphallus; F: flagellum; HD: hermaphroditic duct; P: penis; PR: penis retractor muscle; BC: bursa copulatrix; PBC: pedunculus of bursa copulatrix; VD: vas deferens; S: stylophore or dart sac; AS: accessory sac; MG: mucus glands.