Amphidromus (Syndromus) fuscolabris Mollendorff 1898
Creators: name: Inkhavilay, Khamla
name: Sutcharit, Chirasak
name: Panha, Somsak
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Stylommatophora
Camaenidae
Amphidromus
Amphidromus fuscolabris

description: Amphidromus (Syndromus) fuscolabris Möllendorff, 1898
Figs 1, 9 E–F, 12G–I, 13J–M, 14C–D; Table 1
Amphidromus zebrinus fuscolabris Möllendorff, 1898: 75. Type locality: Boloven (Boloven Plateau, Paksong District, Champasak, Laos).
Amphidromus zebrinus fuscolabris – Pilsbry 1900: 199–200. — Zilch 1953: 134, pl. 23, fig. 22. — Laidlaw & Solem 1961: 564, 621. — Richardson 1985: 49.
Material examined
Type material
LAOS: holotype SMF 7641 (Fig. 13I).
Other material
LAOS: 34 shells, typical form (Fig. 13 J–K, CUMZ 7040); 2 specimens, in ethanol (Figs 9E, 12 G–I, 14C−D, CUMZ 7041); 73 + 10 juveniles, yellowish form (Fig. 13 L–M, CUMZ 7042); 2 specimens, in ethanol (Fig. 9F, CUMZ 7043), Ban Phone, La-Marm District, Sekong; 2 shells, Ban Xai Na Pho, Phatumphone, Champasak (CUMZ 7044).
Description
Shell sinistral, elongate conical, rather solid and glossy. Spire elongate conical; apex acute, with pinkish tint to brownish without black spot on tip. Whorls 6 to 7 nearly smooth; suture wide and shallow; last whorl rounded. Periostracum transparent to thin corneous, with greenish streaks on lower half of last whorl. Last whorl shows yellow to orange Band 1; Bands 2 to 5 merged and become six or seven black or brown slanted blotches; Band 6 yellow; varix absent. Parietal callus thickened, bright purplishpink. Aperture elongated auriform; peristome thickened, expanded and not reflected; lip purplish-pink. Columella rather thick, straight, dilated and purplish-pink. Umbilicus imperforated.
Radula
Each row contains about 161 (80-(35-31)-1-(31-35)-80) teeth. Central tooth unicuspid, with curved cusp. Lateral and marginal teeth similar to that described in A. areolatus. Marginal teeth start from lateral tooth 17 to 21 outwards (Fig. 12 G−I).
Genital organs
Atrium (at) rather long (n = 10). Penis (p) long, cylindrical and slightly swollen at distal end. Epiphallus (e) short, half of penis length; flagellum (fl) of about same length as epiphallus and terminated with pointed tip. Appendix absent. Penial retractor muscle (pr) thin and long. Vas deferens (vd) very narrow tube connecting epiphallus and free oviduct (Fig. 14C).
Internal penial wall corrugated into strong penial pilasters, which form fringe around penial verge. Penial verge conical, with smooth surface and orifice open near tip (Fig. 14D).
Vagina cylindrical, long, slender, about two times as long as penis. Gametolytic duct long, proximal to genital orifice of a relatively larger diameter than vagina and distally tapering; distal to genital orifice small tube of about same length as proximal part and connected to gametolytic sac. Oviduct and albumin gland very small (Fig. 14C).
Internally, vaginal wall shows longitudinal vaginal pilasters (vp); proximal to genital orifice with thin wall and smooth surface, distally pilasters show continuous ridges (Fig. 14D).
Distribution
The original description of this species was given by Möllendorff (1898) and the type locality was Boloven, Laos. Unfortunately, we couldn’t obtain any specimen from the type locality in our recent survey. The specimens were collected from a mountain at Ban Phone (Phone village), Sekong Province, and Ban Xai Na Pho (Xai Na Pho village) Phatumphone, Champasak, Laos, which are both located at a lower altitude than the Boloven Plateau. It seems that this species is only found in low altitude habitats.
Remarks
Amphidromus fuscolabris differs from A. zebrinus and A. eudeli in having a large and elongate shell, apex tinted pink, purplish-pink parietal callus, Band 1 yellowish and Bands 2 to 5 merged and becoming 6 to 7 slanted blotches (on last whorl). In comparison, A. zebrinus (see Sutcharit et al. 2015: fig. 15k) has a smaller shell, Band 1 absent, Bands 2 and 5 merged and becoming fifteen narrow slanted stripes on last whorl, and reddish band in between Bands 5 and 6. On the other hand, A. eudeli (Fig. 13N, holotype RBINS 617427) has a smaller shell, thin parietal callus, Bands 2 and 3 merged and Bands 4 and 5 well developed.
Two color forms were observed from Sekong, Laos. These are the typical form (Fig. 13 I–K) and the yellowish form that is monochrome yellowish, with Bands 2 to 5 absent and stained with pale yellowish color, and Band 6 sometimes present as a brownish color (Fig. 13 L–M). However, these two color forms show a pinkish to purplish-pink parietal callus and columella, and have identical genital structures and sculptures inside the penis and vagina. In addition, they occur sympatrically and so we recognize them as conspecific.
description: Published as part of 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, pp. 1-40 in European Journal of Taxonomy 330 on pages 32-34, DOI: 10.5852/ejt.2017.330, http://zenodo.org/record/3829744