Amphidromus (Syndromus) xiengensis Morlet, 1891

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 : 28-32

Amphidromus (Syndromus) xiengensis Morlet, 1891

Figs 1 , 9 C–D, 12D–F, 13A–H, 14A–B; Table 1

Amphidromus xiengensis Morlet, 1891a: 27 . Type locality: “Xieng-Mai et les forêts des bords du Ménam

Pinh, Laos occidental” (banks of Ping River, Chiang Mai Province, Thailand). Amphidromus contrarius var. multifasciata Fulton, 1896: 78 , pl. 7, fig. 5. Type locality: Cambodia. Amphidromus xiengensis var. clausus Pilsbry, 1900: 195–196 , pl. 63, figs 79−82. Type locality: Laos

Mountain, Cambodia.

Amphidromus porcellanus var. xiengensis – Fulton 1896: 79.

Amphidromus xiengensis – Morlet 1891b: 232, 240–241, pl. 5, fig. 4. — Ancey 1898: 134. — Pilsbry 1900: 194–195, pl. 63, figs 75–76. — Fischer-Piette 1950: 159. — Laidlaw & Solem 1961: 564– 565. — Solem 1965: 626–627, pl. 2, figs 7-13.

Amphidromus xiengensis var. clausus – Solem 1965: 626, pl. 2, figs 11–13.

Amphidromus xiengensis var. multifasciatus – Pilsbry 1900: 195, pl. 63, fig. 77. — Solem 1965: 626.

Material examined

The species was described based on material from Muséum ( MNHN) ex. A. Pavie Collection and did not include an illustration. Morlet (1891b) subsequently re-published the description and illustrated a single specimen. There is a single specimen of L. Morlet in the MNHN collection with an original label stating “Type”. Fischer-Piette (1950: 159) wrote the “ holotype, 38 mm ”, which we consider to be an inadvertent lectotype designation ( ICZN 1999: Art. 74.5). Therefore, lectotype MNHN-IM-130306224 ( Fig. 8A ) was designated by Fischer-Piette (1950: 153) to stabilise the name.

Type material

CAMBODIA: lectotype of var. “ multifasciata ” Fulton, 1896, NHMUK 19601458 ( Sutcharit et al. 2015: fig. 11f); paralectotypes, NHMUK 19601459 (2 shells).

CAMBODIA: lectotype of var. “ clausus ” Pilsbry, 1900, ANSP 31496 ( Fig. 11D ); paralectotypes, ANSP 252752 (2 shells).

Other material

LAOS: 1 shell, Xieng-Moi (W Laos) ( NHMUK 1893.12.8.40, ex. Dautzenberg collection); 32 shells, Ban Phon Pai, Bachieng District, Champasak ( CUMZ 7030); 9 shells, Thad Phasoam, Boloven Plateau, Paksong District, Champasak ( CUMZ 7031); 6 shells, Ban Oudom, Pakbeng District, Oudomxay ( CUMZ 7032); 7 shells, Mouhot’s Tomb, E bank of Kan River, Luang Phrabang District, Luang Phrabang ( CUMZ 7033); 2 specimens, in ethanol ( Figs 9 C–D, 14A–B), Thad Kacham Waterfall, Luang Phrabang District, Luang Phrabang ( CUMZ 7035); 4 shells ( Fig. 13E , CUMZ 7036), 2 specimens, in ethanol ( Fig. 12 D−F, CUMZ 7037), Ban Na Deauy, Luang Phrabang District, Luang Phrabang; 1 specimen, in ethanol, Thad Khaungsy Waterfall, Luang Phrabang District, Luang Phrabang ( CUMZ 7039).

CAMBODIA: 1 shell, Dautzenberg collection ( RBINS); 3 shells, Lao Moutains ( NHMUK 19601539, ex. Cuming Collection).

THAILAND: 1 shell ( Fig. 13B , CUMZ 7050); 1 shell ( Fig. 13C ), Tam Chiang Dao, Chiang Dao District, Chiang Mai ( CUMZ 7034); 1 shell ( Fig. 13F ), Pha Tang, Pong District, Prayao ( CUMZ 7052); 3 shells ( Fig. 13 G–H), Doi Phou Nang National Park, Chiangmouan District, Phayao ( CUMZ 7038).

Description

Shell sinistral, conical to elongate conical, rather thick and glossy. Spire conical; apex acute with brown or black spot on tip. Whorls 6 to 7 slightly convex; suture depressed; last whorl rounded. Periostracum thin and corneous. Last whorl with reddish to brown Band 1; Bands 2 and 3 as concurrent slanted brownish blotches continuous to expanded lip; Bands 4 and 5 with brownish spiral bands; Band 6 absent or yellowish to reddish. Parietal callus transparent or weakly thickened and white. Aperture subovate; peristome rather thick and expanded; lip whitish. Columella thickened, perpendicular and white. Umbilicus narrowly opened to perforated.

Radula

Each row contains about 157 (79-(21-17)-1-(17-21)-77) teeth. Central tooth monocuspid, with spatulate shape. Lateral teeth bicuspid; endocone with elongate shape, curved cusp and separated from truncated or curved cusps of ectocone by wide notch, teeth gradually transformed to tricuspid marginal teeth. Marginal teeth tricuspid starting around teeth number 17 to 21 outwards; endocone curved and pointed cusps; mesocone large, with truncate or obtuse cusps; ectocone small, of triangular shape, with pointed cusp. Outermost teeth with pointed cusps on endocone; mesocone large, with curved cusps; extocone sometimes with serrated shape ( Fig. 12 D−F).

Genital organs

Atrium (at) somewhat short (n = 5). Penis (p) long, cylindrical and enlarged at middle. Epiphallus (e) cylindrical, two times as long as penis; flagellum (fl) short, one third 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. 14A ).

Internal penial wall corrugated into weak penial pilasters, which form fringe around penial verge. Penial verge conical, rough surface and orifice open near tip ( Fig. 14B ).

Vagina cylindrical, long, slender, about 1.5 times as long as penis. Gametolytic duct long, proximal to genital orifice of same diameter as vagina and distally tapering; distal to genital orifice very small tube of about same length as proximal part and connected to gametolytic sac. Oviduct and albumin gland very large ( Fig. 14A ).

Internal wall of vagina shows longitudinal vaginal pilasters (vp); pilasters vary narrow and thin throughout vaginal length ( Fig. 14B ).

Distribution

The species is widely distributed and can be found in several habitats such as forests, fruit orchards and limestone areas between latitudes 14° and 16° N.

Remarks

Amphidromus xiengensis differs from A. areolatus and A. zebrinus in having a larger shell, reddish Band 1, concurrent slanted and brownish blotched Bands 2 and 3, and brownish spiral Bands 4 and 5. In contrast, the other two species have a smaller shell, Band 1 absent and Bands 2 and 3 merged and becoming brownish slanted blotches in A. zebrinus or brownish slanted blotches with a flame shape in A. areolatus . It differs from A. eudeli Ancey, 1897 ( Fig. 13N , syntype RBINS 617427) and A. fuscolabris Möllendorff, 1898 ( Fig. 13I , holotype SMF 7641) in having a white peristome, reddish Band 1, and Bands 2 and 3 usually separated. In comparison, A. fuscolabris shows a purplish-pink peristome, yellowish Band 1, Bands 2 to 5 merged and roseated Band 6, while A. eudeli exhibits a brownish lip, yellow color Band 1 and Bands 2 and 3 usually merged.

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

1. Typical form: Band 1 reddish to brownish; Bands 2 and 3 concurrent slanted brownish blotches continuous to expanded lip; Bands 4 and 5 brownish spiral band; Band 6 absent ( Fig. 13 A–C).

2. var. “ multifasciata ” Fulton, 1896: similar to the typical form, but Band 1 yellowish; Bands 2 and 3 usually divided into several smaller bands; Band 6 reddish ( Fig. 13 G–H; Sutcharit et al. 2015: fig. 11f–g).

3. var. “ clausus ” Pilsbry, 1900: similar to the typical form and var. “ multifasciata ”, but Bands 2 and 3 have disappeared and turned to a pinkish stain on the second half of the last whorl ( Fig. 13 D−F).

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. 8. Genitalia, mating pairs, shell banding formula and radula morphology. A–B. Amphidromus (Syndromus) contrarius (Müller, 1774) from Timor (ZMA). A. Genital system. B. Internal structures of penis and vagina. C. Mating pair of Amphidromus (Syndromus) sp., showing the protruded vaginal simulator pilaster (vsp, red arrows) and its possible function as a stimulating organ. D. Schematic drawing of shell banding, where the numbers 1 to 6 on the last whorl indicate the position of each band. E–G. Radula morphology of Amphidromus (Syndromus) contrarius (Müller, 1774) from Timor (ZMA). E. Central tooth, with the first to fifth lateral teeth. F. Lateral teeth with the tricuspid marginal teeth transition. G. Outermost marginal teeth. Numbers indicate the order of the lateral and marginal teeth. Central tooth indicated by ‘C’.

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. 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).