Amphidromus (Amphidromus) roseolabiatus Fulton, 1896

Inkhavilay, Khamla, Sutcharit, Chirasak & Panha, Somsak, 2017, Taxonomic review of the tree snail genus Amphidromus Albers, 1850 (Pulmonata: Camaenidae) in Laos, with the description of two new species, European Journal of Taxonomy 330, pp. 1-40 : 3-10

Amphidromus (Amphidromus) roseolabiatus Fulton, 1896 Figs 1 , 2 A–B, 3A–B, 4A−F, 6A–B, 7A−C; Table 1

Amphidromus roseolabiatus Fulton, 1896: 89 , pl. 6, fig. 8. Type locality: Siam [ Thailand].

Amphidromus roseolabiatus – Pilsbry 1900: 188, pl. 60, fig. 36. — Laidlaw & Solem 1961: 527. — Richardson 1985: 42. — Schileyko 2011: 57. — Sutcharit et al. 2015: 88 , fig. 13j–k.

Material examined

Type material

THAILAND: Lectotype, NHMUK 19601462 ( Sutcharit et al. 2015: fig. 13j); paralectotype, NHMUK 19601463 (1S shell, Sutcharit et al. 2015: fig. 13k).

Other material

LAOS: 5D + 3S shells, Ban Phone Can, Yommalat District, Khammouan ( CUMZ 7001); 5D + 1S shells, Wat Paphar, Khamkert District, Bolikhamxay ( CUMZ 7002); 2D + 1S shells, Thad Mouang, Khamkert District, Bolikhamxay ( CUMZ 7003); 4D + 10S specimens, in ethanol ( Fig. 4 E–F, CUMZ 7004), 13S specimens in freezer ( Fig. 2B , CUMZ 7005), Tam Mung Korn, Khamkert District, Bolikhamxay; 1D + 1S specimens, in ethanol ( Fig. 4 C–D, CUMZ 7006), 4D + 5S specimens in freezer ( Fig. 3 A–B, CUMZ 7007), Nam Turn Bridge, Khamkert District, Bolikhamxay; 8D + 6S shells, Limestone quarry, Bolikhamxay ( CUMZ 4013); 4D + 3S shells, pink aperture, Km. 70 on the road from Laos to Vietnam border, Yommalat District, Khammouan ( CUMZ 7008); 8D shells, pink aperture, Tam Narng Lod, Yommalat District, Khammouan ( CUMZ 7009); 3D + 1S shells, pink aperture, Hauy In River, Yommalat District, Khammouan ( CUMZ 7010); 12D + 8S specimens, in ethanol, pink aperture ( Fig. 4 A–B, CUMZ 7011), 5D specimens, in ethanol ( Figs 2A , 6 A–B, 7A−C, CUMZ 7012), Ban Pha Vong, Yommalat District, Khammouan; 1D + 1S shells, pink aperture ( CUMZ 7013), 6D specimens, in ethanol ( CUMZ 7047), 4D specimens, in ethanol ( CUMZ 7048), 1D + 1S shells, pink aperture ( CUMZ 7035), Thad Khaungsy Waterfall, Luang Phrabang District, Luang Phrabang; 6D shells ( CUMZ 40107), 10S + 21D shells ( CUMZ 7049), Ban Phahom, Vang Vieng District, Vientiane.

VIETNAM: 2D+3S shells, Phong Nha National Park ( CUMZ 7053).

THAILAND: 1D shell, Nan Province, Thailand ( CUMZ 7054).

Description

Shell chirally dimorphic, elongate to ovate conical, rather thin and glossy. Spire conical; apex acute, light brown and without black spot on tip. Whorls 6 to 7 nearly smooth; suture wide and depressed; last whorl rounded. Periostracum usually deciduous to yellowish-green radial streaks, more conspicuous on last whorl and faded in previous whorls. Last whorl processes thin, whitish subsutural band, sometimes with one or two reddish-brown spiral bands below periphery but usually not reaching lip; varix absent. Parietal callus thin and transparent. Aperture ovate to elongate; peristome expanded and not reflected; lip usually purplish-pink or white. Columella straight, thickened, purplish-pink or white. Umbilicus narrowly opened.

Radula

Each row contains about 130 (66-(10-6)-1-(6-10)-63) teeth. Central tooth unicuspid and spatulate with curved cusp. Lateral teeth bicuspid. Endocone cylindrical, slightly oblique, with wide notch; ectocone large, with truncated to rounded cusp. Marginal teeth tricuspid, start around tooth number 6 to 10; endocone small; mesocone large, with rounded cusp, ectocone small, with sharp cusp. Outermost teeth with small and sharp cusp on endocone and extocone; mesocone large, with curved cusps ( Fig. 7 A−C).

Genital organs

Atrium (at) rather short (n = 10). Penis (p) long and stout. Epiphallus (e) long, about two times as long as penis; flagellum (fl) longer than epiphallus and terminated in folded coil. Appendix very small, extends from folded coil of flagellum, about same length as epiphallus. Penial retractor muscle (pr) short, thickened and inserted distally on penis. Vas deferens (vd) narrow tube connecting epiphallus and free oviduct ( Fig. 6A ).

Internal penial wall corrugated into series of thick penial pilasters (pp), which form a fringe around penial verge. Penial verge (pv) rather long and curved, conical, with smooth surface and orifice located at tip ( Fig. 6B ).

Vagina cylindrical, about two times as long as penis. Gametolytic duct very long, proximal to genital orifice large, coiled; distal to genital orifice tapering to small tube, short, about one-third length of proximal part and connected to enlarged gametolytic sac. Oviduct and albumin gland small ( Fig. 6A ).

Internally, vaginal wall performs longitudinal vaginal pilasters (vp); proximal to genital orifice with small corrugated continuous ridges, ridges distally becoming smooth ( Fig. 6B ).

Distribution

This species is distributed widely, from many localities in central and northern Laos. There are also records from Nan Province, Thailand and Phong Nha National Park, Vietnam.

Remarks

Amphidromus roseolabiatus differs from A. smithi Fulton, 1896 and A. ventrosulus Möllendorff, 1900 ( Zilch 1953; Sutcharit et al. 2015) in having an enantiomorphic shell coiling, purplish-pink lip and fine green streaks. In contrast, A. smithi has a sinistral shell, brownish lip with dark spot on the apex, and A. ventrosulus has a sinistral shell, uniform green color, elongate spire and more depressed suture.

Laidlaw & Solem (1961) recognized A. roseolabiatus as belonging to an uncertain subgenus that was probably close to the subgenus Syndromus . However, this species exhibits dimorphic shell coiling with a long flagellum and appendix, which are typical characters of the nominotypical subgenus ( Fig. 6A ). Two color forms were observed in the recently collected materials. The typical color form has a greenish radial streaked periostracum and pinkish apertural lip ( Figs 2A , 4 A–B). There are some specimens with the typical color form showing one or two additional reddish-brown lower, peripheral bands ( Fig. 4B ). The second, whitish form usually has a greenish periostracum, as in the typical color form, but a white apertural lip ( Figs 2B , 4 C–F). However, these two color forms have identical genital structures and sculptures inside the penis and vagina.

Figures

Fig. 1. Distribution map of Amphidromus spp. in Laos recognized in this study.

Fig. 2. Living snails. A–B. Amphidromus roseolabiatus Fulton, 1896. A. Typical form from Ban Phavong, Khammouan, Laos (CUMZ 7012). B. Form with white lip from Tam Mung Korn, Bolikhamxay, Laos (CUMZ 7005). C. Amphidromus givenchyi Geret, 1912 from Thad Lor Waterfall, Salavan, Laos (CUMZ 7018). D. Amphidromus syndromoideus sp. nov., holotype from the type locality (CUMZ 7019).

Fig. 4. Shells of Amphidromus (Amphidromus) spp. A−F. Amphidromus roseolabiatus Fulton, 1896. A–B. Typical form from Ban Phavong, Khammouan, Laos (CUMZ 7011). C–D. Form with white lip from Nam Turn Bridge, Bolikhamxay, Laos (CUMZ 7006). E–F. Form with white lip from Tam Mung Korn, Bolikhamxay, Laos (CUMZ 7004). G. Amphidromus laosianus Bavay, 1898 from Khone, Champasak, Laos (RMNH 101049). H. Amphidromus protania Lehmann & Maassen, 2004, holotype (RMNH 98143). I. Amphidromus givenchyi Geret, 1912 from Thad Lor Waterfall, Salavan, Laos (CUMZ 7015). J–K. Amphidromus syndromoideus sp. nov. from the type locality. J. Holotype (CUMZ 7019). K. Paratype (CUMZ 7020).

Fig. 3. Aestivation sites of Amphidromus species. A–B. Amphidromus roseolabiatus Fulton, 1896 (shell height about 34 mm) from NamTurn Bridge, Bolikhamxay, Laos, aestivated. A. Inside sterile fronds of stag horn ferns, Platycerium Desv. B. In a small hole on a Jackfruit tree trunk, Artocarpus heterophyllus Lam., with other snails, Quantula Baker, 1941 and Durgella Blanford, 1863. C. Amphidromus givenchyi Geret, 1912 (shell height about 43 mm), hiding in a small hole of a dipterocarpus tree shell. D. Amphidromus syndromoideus sp. nov. (shell height about 28 mm) from the type locality, hiding in a hole of a tree, visible after removal of clusters of sterile fronds of the basket fern Drynaria (Bory) J. Sm.

Fig. 6. Genitalia of Amphidromusspp. A–B. Amphidromus roseolabiatus Fulton, 1896 from Ban Phavong, Khammouan, Laos showing reproductive system and interior structures of penis and vaginal chamber (CUMZ 7012). C–D. Amphidromus syndromoideus sp. nov., holotype, showing general characteristics of the genital system and interior structures of penis and vagina chamber (CUMZ 7019).

Fig. 7. SEM images of the radula. A–C. Amphidromus roseolabiatus Fulton, 1896 from Ban Phavong, Khammouan, Laos (CUMZ 7012). D–F. Amphidromus syndromoideus sp. nov., holotype (CUMZ 7019). G–I. Amphidromus areolatus (Pfeiffer, 1861) from Thad Fek, Attapue, Laos (CUMZ 7023). A, D, G = central tooth with the first to fifth to eighth lateral teeth; B, E, H = lateral teeth with the tricuspid marginal teeth transition; C, F, I = outermost marginal teeth. Numbers indicate the order of the lateral and marginal teeth. Central tooth indicated by ‘C’.