Amphidromus pankowskianus Thach, 2020

Jirapatrasilp, Parin, Huang, Chih-Wei, Sutcharit, Chirasak & Lee, Chi-Tse, 2024, The arboreal snail genus Amphidromus Albers, 1850 (Eupulmonata, Camaenidae) of Southeast Asia: 1. Molecular systematics of some Vietnamese species and related species from Cambodia, Indonesia, and Laos, ZooKeys 1196, pp. 15-78 : 15

Amphidromus pankowskianus Thach, 2020

Figs 28D, E , 30G-L , 31

Amphidromus pankowskiana [sic] Thach, 2020a: 72-73, pl. 48, figs 582-586. Type locality: Northwestern District of Khanh Hoa Province, Central Vietnam.

Amphidromus pankowskianus. Thach 2021: 72.

Material examined.

Vietnam: Holotype, NHMUK 20200213 (Fig. 30G ).

Other material examined.

Laos: 2D + 1S specimens, Khammouan Province, near Minh Hoa District, Quang Binh Province, Vietnam, NMNS-8764-150- NMNS-8764-152 (Fig. 30K, L ); 23D + 17S specimens, Lak Sao, Khamkeut District, Bolikhamsai Province, NMNS-8764-153- NMNS-8764-191, NMNS-8764-212 (Fig. 30H-J ).

Diagnosis.

Shell medium and chirally dimorphic. Last whorl without or with narrow to spiral band on periphery. Parietal callus transparent; lip and columella pale purplish pink; dark radial band on palatal wall. Genitalia with appendix.

Differential diagnosis.

This species is very closely similar to A. roseolabiatus in terms of shell morphology and colour pattern. However, this species is distinct in having a dark radial band behind the reflected lip which is also visible in the inner side of the shell and sometimes with a dark spiral band below periphery. In addition, this species also differs from A. haematostoma and A. madelineae in having a chirally dimorphic shell, with dark radial bands behind the expanded lip, and the genitalia with a long flagellum. The molecular phylogeny in this study reveals that A. pankowskianus constitutes its own distinct clade which is sister to A. roseolabiatus (Fig. 2 ). The COI and 16S p -distances between A. pankowskianus and A. roseolabiatus are 13.02% and 6.14%, respectively (Table 2 ).

Description.

Shell medium (height 30.8-39.9 mm, width 17.2-19.2 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 without or with narrow to wide brownish spiral band on periphery; varix absent. Parietal callus thin and transparent. Aperture ovate; peristome expanded and not reflected; lip pale purplish pink. Outer palatal wall with dark radial band just next to expanded lip (also visible on inner wall) and brownish radial band encircled umbilicus present (sometimes absent). Umbilicus narrowly opened.

Genital organs. Atrium relatively short. Penis enlarged, conical, and almost as long as vagina. Penial retractor muscle thin and inserting on epiphallus close to penis. Epiphallus thin and long slender tube, and approximately as long as penis. Flagellum short, extending from epiphallus, ~ 1/2 of penis length, and terminating in slightly enlarged coil. Appendix short, slender tube, nearly as long as epiphallus. Vas deferens slender tube passing from free oviduct and terminating at epiphallus-flagellum junction (Fig. 28D ). Internal wall of penis corrugated, exhibiting series of weak longitudinal penial pilasters forming fringe around penial wall, and with smooth wall around base of penial verge. Penial verge very short conical with opening at the tip (Fig. 28E ).

Vagina slender, cylindrical, and approximately as long as penis. Gametolytic duct cylindrical tube, similar diameter as vagina then tapering to slender tube terminally and connected to enlarged elliptical gametolytic sac (missing during dissection). Free oviduct short; oviduct forming lobule alveoli (Fig. 28D ). Internal wall of vagina possessing smooth ridges near genital orifice; ridges becoming swollen and corrugated longitudinal vaginal pilasters in middle, and with deep crenelations close to free oviduct opening (Fig. 28E ).

Haplotype network.

There was a total of five COI haplotypes of A. pankowskianus in this study, and the highest number of mutational steps in the COI minimum spanning network is two (Fig. 31 ).

Distribution.

This species is found in Bolikhamsai and Khammouan provinces, Laos, and Khanh Hoa Province, Vietnam.

Remarks.

Empty shells from Phong Nha National Park, Quang Binh Province, Vietnam, identified as ' A. roseolabiatus ' in Inkhavilay et al (2017: CUMZ 7053; 2D+3S shells) possess a transparent parietal callus with a dark radial band on the palatal wall just next to the lip. This specimen lot could probably be assigned to A. pankowskianus instead. Future molecular evidence is needed to shed light on the systematic status of this population.

Figures

Figure 2. Bayesian phylogeny of Amphidromus spp. based on mitochondrial COI and 16 S genes. Nodal support values are given as SH-aLRT / aBayes / ultra-fast bootstrap (IQ-TREE, ML) / posterior probability (MrBayes, BI). An asterisk on each branch indicates a clade with all well-supported values (SH-aLRT ≥ 80 %, aBayes ≥ 0.95, BS ≥ 95 %, PP ≥ 0.95). Species numbers correspond to those in Fig. 1 and Tables 1, 2.

Figure 28. Genitalia of Amphidromus spp A-C Amphidromus costifer Smith, 1893 from Ea Sup, Dak Lak, Vietnam (NMNS- 8764 - 048), showing A general view of genitalia B interior structures of penis C interior structures of vagina chamber D, E Amphidromus pankowskianus Thach, 2020 from Khammouan Province, Laos, near Minh Hoa District, Quang Binh Province, Vietnam (NMNS- 8764 - 152), showing D general view of genitalia E interior structures of penis and vagina chamber. Red dots indicate the shape of the missing gametolytic sac. Green arrows indicate the genital openings. Abbreviations: ap, appendix; e, epiphallus; fl, flagellum; fo, free oviduct; gd, gametolytic duct; gs, gametolytic sac; ov, oviduct; p, penis; pp, penial pilaster; pr, penial retractor muscle; pv, penial verge; v, vagina; vd, vas deferens; vp, vaginal pilaster.

Figure 30. Shells of Amphidromus spp A-F Amphidromus roseolabiatus Fulton, 1896 A lectotype of " Amphidromus roseolabiatus " (NHMUK 19601462) B paralectotype of " Amphidromus roseolabiatus " (NHMUK 19601463) C holotype of " Amphidromus phuonglinhae " (MNHN-IM- 2000 - 33200) D-F specimens from Kampong Siem, Kampong Cham, Cambodia (NMNS- 8764 - 254, NMNS- 8764 - 258, NMNS- 8764 - 260) G-L Amphidromus pankowskianus Thach, 2020 G holotype (NHMUK 20200213) H-J specimens from Lak Sao, Khamkeut, Bolikhamsai, Laos (NMNS- 8764 - 154, NMNS- 8764 - 170, NMNS- 8764 - 192) K, L specimens from Khammouan Province, Laos, near Minh Hoa District, Quang Binh Province, Vietnam (NMNS- 8764 - 150, NMNS- 8764 - 151). Credit: M. Caballer (C), K. Webb (G).

Figure 31. Mitochondrial COI haplotype minimum spanning networks of Amphidromus roseolabiatus Fulton, 1896 and Amphidromus pankowskianus Thach, 2020. The size of each circle corresponds to the frequency of that haplotype, also shown as the number in that circle. The bars on the branches indicate the number of mutational steps between haplotypes. Specimen codes correspond to those in Table 1.