Amphidromus (Syndromus) flavus (Pfeiffer, 1861)

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 : 24-26

Amphidromus (Syndromus) flavus (Pfeiffer, 1861)

Figs 1 , 9B , 10 E−K, 11C–D, 12A−C; Table 1

Bulimus flavus Pfeiffer, 1861a: 194 . Type locality: Siam [ Thailand].

Amphidromus flavus var. proxima Fulton, 1896: 81 , pl. 6, fig. 4. Type locality: Unknown. Sutcharit et al. 2015: 85, fig. 13c.

Amphidromus xiengensis var. tryoni Pilsbry, 1900: 196–197 , pl. 63, fig. 78. Type locality: Laos Mountains, Cambodia.

Amphidromus sinensis var. indistinctus Pilsbry, 1900: 192 , pl. 62, fig. 70. Type locality: Laos Mountains, Cambodia.

Bulimus flavus – Pfeiffer 1861b: 171, pl. 46, figs 7–8. — Morelet 1875: 265.

Amphidromus flavus – Fulton 1896: 81. — Ancey 1898: 134. — Pilsbry 1900: 197–198, pl. 63, figs 92–93. — Laidlaw & Solem 1961: 563–564, 619.

Amphidromus flavus var. proximus – Pilsbry, 1900: 198, pl. 63, fig. 94.

Amphidromus xiengensis var. proxima – Laidlaw & Solem 1961: 565, 652.

Material examined

Type material

THAILAND: Lectotype, NHMUK 19601436 ( Sutcharit et al. 2015: fig. 7i); paralectotype, NHMUK 19601437 (1 shell).

UNKNOWN LOCALITY: Holotype of var. “ proxima ” Fulton, 1896, NHMUK 1896.6.13.48 ( Sutcharit et al. 2015: fig. 13c).

CAMBODIA: Holotype of var. “ indistinctus ” Pilsbry, 1900, ANSP 31486 ( Fig. 10 H ).

CAMBODIA: Lectotype of var. “ tryoni ” Pilsbry, 1900, ANSP 31488 ( Fig. 10 I ); paralectoypes, ANSP 252745 (2 shells, Fig. 10 J ).

Other material

LAOS: 5 shells, park at the temple mountain, Luang Phrabang ( NHMUK ex. Brandt collection No. 17320); 20 shells, Tempelberg (Temple Mount), Luang Phrabang ( ZMB ex. Lehmann collection); 33 shells, Wat Phousy (temple), Luang Phrabang ( CUMZ 7025); 3 shells ( Fig. 10 K , CUMZ 7026), 7 specimens, in ethanol ( Figs 9 B , 11 C–D, 12A−C, CUMZ 7027), Ban Na Deauy, Luang Phrabang District, Luang Phrabang; 5 shells, Mouhot’s Tomb, E bank of Kan River, Luang Phrabang District, Luang Phrabang ( CUMZ 7028); 16 shells ( Fig. 10 E−G), Tam Pou Kham, Vang Vieng District, Vientiane ( CUMZ 7029).

Description

Shell sinistral, small, ovate conical, small, thin and glossy. Spire conical; apex acute yellowish, with black spot on tip. Whorls 5 and 6 convex; suture depressed; last whorl rounded to well rounded. Periostracum transparent to thin corneous. Last whorl processes uniform yellowish; Bands 1 to 3 usually absent; Bands 4 and 5 absent or present with indistinct bands; Band 6 usually absent or sometimes present as scantly reddish band. Parietal callus thin and transparent.Aperture ovate to sub-ovate; peristome weakly thickened and shortly expanded; lip whitish. Columella straight and white. Umbilicus opened to narrowly opened. Radula

Teeth arranged in V-shaped rows, each row contains about 166 (84-(7-10)-1-(8-12)-81) teeth. Central tooth tricuspid; mesocone of triangular shape; ectocones small, with pointed cusp. Lateral teeth tricuspid; endocone small and rounded cusps; mesocone large and truncated cusp; ectocone very small, pointed cusp and located at base of teeth. Lateral teeth gradually transformed to elongated marginal teeth. Marginal teeth tricuspid, start around tooth number 8 to 12; endocone elongate with dull cusps and separated from mesocome by wide notch; mesocone large, elongate and curved cusps; ectocone small, with pointed cusps or sometimes serrated shape ( Fig. 12 A−C).

Genital organs

Atrium (at) rather long (n = 5). Penis (p) long, cylindrical and enlarged from middle to end. Epiphallus (e) cylindrical, length longer than that of penis; flagellum (fl) short and one fourth as long as epiphallus; appendix absent. Penial retractor muscle (pr) thickened and relatively short. Vas deferens (vd) small tube, connecting epiphallus and free oviduct ( Fig. 11C ).

Internal penial wall corrugated into thin penial pilasters, which form fringe around penial verge. Penial verge conical, with smooth surface and orifice open near tip ( Fig. 11D ).

Vagina cylindrical, long, slender about two times as long as penis length. Gametolytic duct long, proximal to genital orifice almost same diameter as vagina, distally tapering; distal to genital orifice small tube of about same length as proximal part and connected to gametolytic sac. Oviduct and albumin gland small ( Fig. 11C ).

Internally, vaginal wall shows longitudinal vaginal pilasters (vp); pilasters very narrow and thin ( Fig. 11D ).

Distribution

The distribution range of the species is from Vientiane to Luang Phrabang Provinces.

Remarks

Amphidromus flavus differs from A. sinensis (Benson, 1851) in having a smaller shell, the spire more ovate and conical, with a single reddish band on the penultimate whorl. It can be distinguished from A. xiengensis in having a smaller shell, ovate conical, without any band on yellowish ground color or on shell sculpture. It differs from A. globonevilli Sutcharit & Panha, 2015 by having a larger shell size, and it is smaller than A. principalis Sutcharit & Panha, 2015 . In comparison, A. globonevilli has an elongate conical shell and a faint yellow spiral band below the periphery, while A. principalis has a more elongate conical shell, last whorl without any band, aperture ovate. In our collection we found two types identified as A. flavus and A. flavus var. “ proxima ”, living sympatrically at Luang Phrabang and Vang Vieng.

Three subspecific entities have been proposed; however, we recognize them as a single biological species, A. flavus .

1. Typical form: monochrome yellowish shell and Bands 1 to 6 absent ( Sutcharit et al. 2015: fig. 7i–j, for the lectotype and paralectotype).

2. var. “ proxima ” Fulton, 1896: monochrome yellowish shell, Bands 4 and 5 are indistinct pale brownish bands ( Sutcharit et al. 2015: fig. 13c, for the holotype).

3. var. “ tryoni ” Pilsbry, 1900: Band 1 yellowish, Bands 2 and 3 absent, Bands 4 and 5 brownish and Band 6 absent. In some specimens, brownish blotches of Bands 2 and 3 present in the earlier whorls and disappeared in the penultimate and last whorls ( Fig. 10 I−K).

4. var. “ indistinctus ” Pilsbry, 1900: identical to var. “ proxima Fulton, 1896 ” ( Fig. 10H ).

Figures

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

Fig. 9. Living snails of Amphidromus (Syndromus) spp. A. Amphidromus areolatus (Pfeiffer, 1861) from Thad Fek, Attapeu, Laos (CUMZ 7023). B. Amphidromus flavus (Pfeiffer, 1861) from Ban Na Deauy, Luang Phrabang, Laos (CUMZ 7027). C–D. Amphidromus xiengensis Morlet, 1891 from Thad Kacham, Luang Phrabang, Laos (CUMZ 7035), the typical form, and var. “multifasciata” Fulton, 1896, respectively. E–F. Amphidromus fuscolabris Möllendorff, 1898 from Ban Phone, Sekong, Laos (CUMZ 7041–7042). E. Typical color form. F. Monochrome yellowish color form.

Fig. 10. Shells of Amphidromus (Syndromus) spp. A−C. Amphidromus areolatus (Pfeiffer, 1861) from Thad Fek, Attapeu, Laos (CUMZ 7022). D. Amphidromus begini (Morlet, 1886), syntype from Strung- Trang, Cambodia (MNHN-IM-2000-1832). E-G. Amphidromus flavus (Pfeiffer, 1861) from Tam Pou Kham, Vientiane, Laos (CUMZ 7029). H. Amphidromus flavus var. “indistinctus” Pilsbry, 1900, holotype (ANSP 31486). I–K. Amphidromus flavus var. “tryoni” Pilsbry, 1900. I. Lectotype (ANSP 31488). J. Paralectotype (ANSP 252745). K. Specimen from Ban Na Deauy, Luang Phrabang, Laos (CUMZ 7026). L–M. Amphidromus semitessellatus (Morlet, 1884). L. Lectotype (MNHN-IM-2000-1985). M. Specimen from Cambodia (NHMUK).

Fig. 11. Genitalia of Amphidromus (Syndromus) spp. A–B. Amphidromus areolatus (Pfeiffer, 1861) from Thad Fek, Attapeu, Laos showing the reproductive system and interior structures of the penis and vaginal chamber (CUMZ 7023). C–D. Amphidromus flavus (Pfeiffer, 1861) from Ban Na Deauy, Luang Phrabang, Laos showing the general characteristics of the genital system and the interior structures of the penis, atrium and vagina chamber (CUMZ 7027).

Fig. 12. SEM images of the radula. A–C. Amphidromus flavus (Pfeiffer, 1861) from Ban Na Deauy, Luang Phrabang, Laos (CUMZ 7027). D–F. Amphidromus xiengensis Morlet, 1891 from Ban Na Deauy, Luang Phrabang, Laos (CUMZ 7037). G–I. Amphidromus fuscolabris Möllendorff, 1898 from Ban Phone, Sekong, Laos (CUMZ 7041). A, D, G = central tooth with the first to fifth or sixth 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’.