Amphidromus (Syndromus) semitessellatus ( Morlet, 1884 )

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 : 27-28

Amphidromus (Syndromus) semitessellatus ( Morlet, 1884)

Fig. 10 L–M

Bulimus (Amphidromus) semitessellatus Morlet, 1884: 387 , 388, pl. 11, figs 2, 2a. Type locality: “Les montagnes qui bordent le grand fleuve au delà de Stung-Treng. Les forêts et les montagnes de Kampot à Campong-Som” (Mountains along the great river behind Stung-Treng. Forests and mountains of Kampot and Sihanoukville Provinces, Cambodia).

Amphidromus semitessellatus – Morlet 1889: 128. — Fulton 1896: 87. — Pilsbry 1900: 194, pl. 60, figs

41–44. — Laidlaw & Solem 1961: 564. — Solem 1965: 625–626, pl. 2, fig. 2. — Richardson 1985: 43. Bulimus (Amphidromus) semitessellatus – Fischer-Piette 1950: 153.

Material examined

This species was described from specimens collected by A. Pavie from the L. Morlet collection. The original description includes an illustration of a single shell, one set of shell measurements, and a species description that may be based on one unknown specimen. There is a single specimen of L. Morlet in the MNHN collections, with an original label stating “Type”. Fischer-Piette (1950: 153) wrote the “ holotype, 35 mm ”, which we consider to be an inadvertent lectotype designation ( ICZN 1999: Art.

74.5). Therefore, lectotype MNHN-IM-2000-1985 ( Fig. 10 L ) was designated by Fischer-Piette (1950: 153) to stabilise the name.

CAMBODIA: 3 shells ( RBINS Dautzenberg collection); 1 juvenile ( Fig. 10 M ) ( NHMUK).

Description

Shell sinistral, elongate conical, thickened 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. Last whorl monochrome whitish, with black Band 1 and Bands 2 to 6 absent; spire with concurrent brownish blotches of Bands 2 and 3. Parietal callus thickened and transparent or white. Aperture subovate; peristome rather thickened, expanded and weakly reflected; lip whitish. Columella thickened, perpendicular and white. Umbilicus narrowly opened to perforate.

Remarks

Previous records of this species were from the type locality in Stung Treng Province in the north and Kampot and Sihanoukville Provinces in the south of Cambodia, and later from Srakeo Province, Thailand. Laidlaw & Solem (1961: 658) mentioned that the distribution range of this species was in Laos. However, no specimens were collected and, therefore, new records of this species in Laos are required to confirm its precise distribution.

Amphidromus semitessellatus can be distinguished from A. flavus and A. xiengensis by having a solid shell, with black Band 1, last whorl monochrome whitish, Bands 2 to 6 absent, and spire with concurrent brownish blotches of Bands 2 and 3. In comparison, A. flavus has a yellowish and thin shell, Bands 1 to 6 usually absent, but sometimes Bands 4 and 5 present and with scantly reddish Band 6. Meanwhile, A. xiengensis exhibits a yellowish ground color, thinner shell, reddish Band 1, Bands 2 and 3 with concurrent brownish slanted blotches, dark brown Bands 4 and 5, and yellowish or reddish Band 6.

Similar to the previous species, color variation occurs in this species in having concurrent brownish blotches of Bands 2 and 3 on the first half of the last whorl and blackish spiral Bands 4 and 5 present, but not continuing to the lip, and a black Band 6.

Figures

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).