Amphidromus roseolabiatus Fulton, 1896

Figs 30A-F, 31

Amphidromus roseolabiatus Fulton, 1896: 89, pl. 6, fig. 8. Type locality: Siam [Thailand]. Pilsbry 1900: 188, pl. 60, fig. 36. Fischer and Dautzenberg 1904: 407. Laidlaw and Solem 1961: 527, 655. Richardson 1985: 42. Schileyko 2011: 51. Sutcharit et al. 2015: 88, fig. 13j, k. Inkhavilay et al. 2019: 94, figs 45d-f, 58a. Páll-Gergely et al. 2020: 54. Thach 2020b: 360, fig. 7.

Amphidromus Amphidromus (Amphidromus) roseolabiatus . Inkhavilay et al. 2017: 3, 6, 9, 10, figs 2a, b, 3a, b, 4a-f, 6a, b, 7a-c.

Amphidromus phuonglinhae Thach, 2017: 45, pl. 46, figs 581-584. Type locality: Bo Trach District, Quang Binh Province, Central Vietnam. Thach 2021: 76.

Material examined.

Thailand: Sinistral, lectotype of " Amphidromus roseolabiatus ", NHMUK 19601462 (Fig. 30A); 1S, paralectotype of " Amphidromus roseolabiatus ", NHMUK 19601463 (Fig. 30B) .

Vietnam: Sinistral, holotype of " Amphidromus phuonglinhae ", MNHN-IM-2000-33200 (Fig. 30C) .

Other material examined.

Cambodia: 4D + 6S specimens, Kampong Siem District, Kampong Cham Province, NMNS-8764-254- NMNS-8764-263 (Fig. 30D-F).

Diagnosis.

Shell medium and chirally dimorphic. Parietal callus transparent; lip and columella purplish pink. Genitalia with appendix.

Differential diagnosis.

This species is very closely similar to A. pankowskianus in terms of shell morphology and colour pattern. However, this species lacks a dark radial band behind the reflected lip which is also visible in the inner side of the shell, and a dark spiral band below periphery, both of which are present in A. pankowskianus . Amphidromus roseolabiatus differs from the similar species A. madelineae and A. haematostoma in having a chirally dimorphic shell, and genitalia with a very long appendix, while both A. madelineae and A. haematostoma are exclusively sinistral, and the genitalia lacks an appendix. Amphidromus roseolabiatus also differs from both A. smithi Fulton, 1896 and A. ventrosulus Möllendorff, 1900 from Vietnam (Zilch 1953; Sutcharit et al. 2015) in having a chirally dimorphic shell, a purplish pink lip and fine green streaks. In contrast, A. smithi has a sinistral shell, a dark red to brownish lip with dark spot on the apex, and A. ventrosulus has a sinistral shell, uniform green colour, elongate spire and more depressed suture. The molecular phylogeny in this study reveals that A. roseolabiatus is a distinct clade from its sister A. pankowskianus (Fig. 2). The COI and 16S p -distances between A. roseolabiatus and A. pankowskianus are 13.02% and 6.14%, respectively (Table 2).

Description.

Shell medium (height 33.1-38.6 mm, width 19.2-21.6 mm), chirally dimorphic, elongate to ovate conical, rather thin and glossy. Spire conical; apex acute, light brown and without black spot on tip. Whorls 6-7 nearly smooth; suture wide and depressed; last whorl rounded. Periostracum usually deciduous to yellowish green radial streaks, more conspicuous on last whorl and faded in earlier whorls. Last whorl with thin, whitish subsutural band; with or without reddish brown spiral band on periphery but usually not reaching apertural lip; varix absent. Parietal callus thin and transparent. Aperture ovate to elongate; peristome expanded and not reflected; lip usually purplish pink. Columella straight, thickened, purplish pink. Umbilicus narrowly opened.

Haplotype network.

There was one COI haplotype of A. roseolabiatus in this study (Fig. 31).

Distribution.

This species is found in Khammouan Province, Laos, Kampong Cham Province, Cambodia, and Quang Binh Province, Vietnam. The distribution of this species in Bolikhamxay, Laos according to Inkhavilay et al. (2017) is dubious (see below).

Remarks.

Inkhavilay et al. (2017) also included the white-lipped morph from Bolikhamxay, Laos in A. roseolabiatus . However, in this study we only incorporated the typical purplish pink-lipped morph in the phylogenetic analyses. Therefore, the identification of the white-lipped morph from Bolikhamxay, Laos as A. roseolabiatus or another distinct species remains to be further investigated.