Amphidromus (Syndromus) fuscolabris Möllendorff, 1898

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 : 32-34

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.

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. 13. Shells of Amphidromus (Syndromus) spp. A−C. Amphidromus xiengensis Morlet, 1891. A. Lectotype (MNHN-IM-2000-5249). B. Specimen from Thailand (CUMZ 7050). C. Specimen from Tam Chiang Dao, Chiangmai, Thailand (CUMZ 7034). D−F. Amphidromus xiengensis var. “clausus” Pilsbry, 1900. D. Lectotype (ANSP 31496). E. Specimen from Ban Na Deauy, Luang Phrabang, Laos (CUMZ 7036). F. Specimen from Pha Tang, Prayao, Thailand (CUMZ 7052). G–H. Amphidromus xiengensis var. “multifasciata” Fulton, 1896 from Phu Nang National Park, Phayao, Thailand (CUMZ 7038). I−M. Amphidromus fuscolabris Möllendorff, 1898. I. Holotype (SMF 7641). J−M. Specimens from Ban Phon, Sekong, Laos (CUMZ 7041–7042). N. Amphidromus eudeli Ancey, 1897, syntype from Binh Dinh, Annam (RBINS 617427). O–P. Amphidromus haematostoma Möllendorff, 1898. O. Lectotype (SMF 7559). P. Paralectotype (SMF 7560). Q–R. Amphidromus haematostoma var. “varians” Möllendorff, 1898. Q. Lectotype (SMF 7561). R. Paralectotype (SMF 7562). S–T. Amphidromus xiengkhaungensis sp. nov. S. Holotype (CUMZ 7045). T. Paratype (CUMZ 7046).

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’.

Fig. 14. Genitalia of Amphidromus (Syndromus) spp. A–B. Amphidromus xiengensis Morlet, 1891 from Luang Phrabang showing the reproductive system and interior structures of the penis and vaginal chamber (CUMZ 7035). C–D. Amphidromus fuscolabris Möllendorff, 1898 from Ban Phone, Sekong, Laos showing the general characteristics of the genital system and the interior structures of the penis, atrium and vaginal chamber (CUMZ 7041).