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 Author Jirapatrasilp, Parin https://orcid.org/0000-0002-5591-6724 Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand & Leibniz Institute for the Analysis of Biodiversity Change, Martin-Luther-King-Platz 3, Hamburg, Germany Author Huang, Chih-Wei https://orcid.org/0000-0002-2921-4294 School of Life Science, National Taiwan Normal University, Taipei, Taiwan Author Sutcharit, Chirasak https://orcid.org/0000-0001-7670-9540 Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand jirasak4@yahoo.com Author Lee, Chi-Tse https://orcid.org/0000-0003-2695-0680 Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan leechitse@yahoo.com.tw text ZooKeys 2024 2024-03-22 1196 15 78 http://dx.doi.org/10.3897/zookeys.1196.112146 journal article http://dx.doi.org/10.3897/zookeys.1196.112146 1313-2970-1196-15 7954DFBF803A48F5B79142DD09FE5D01 E53B8BDDAE9B58BDBE4B7058562B2B14 Amphidromus ingens Moellendorff , 1900 Figs 3 , 4A , 5A-C , 6A-C , 7 Amphidromus ingens Moellendorff , 1900b: 23-24. Type locality: Berg "Mutter und Kind", Annam [Vietnam]. Pilsbry 1900 : 175-176. Fischer and Dautzenberg 1904 : 406. Laidlaw and Solem 1961 : 529, 629. Richardson 1985 : 21. Thach 2005 : 235, pl. 73, fig. 22. Schileyko 2011 : 50. Sutcharit et al. 2021 : fig. 1g. Amphidromus Amphidromus (Amphidromus) ingens . Zilch 1953 : 135, pl. 23, fig. 25. Amphidromus naggsi Thach & Huber, 2014: 35-37, figs 1-13, 15. Type locality: Don Duong district, Lam Dong Province, South Vietnam. Pall-Gergely et al. 2020 : 53. Thach et al. 2020 : 185, 187, pl. 1, fig. 6a. Thach 2020a : 70, fig. 881 left. Thach 2021 : 70. syn. nov. Material examined. Vietnam : Dextral , lectotype of " Amphidromus ingens ", SMF 7565/1 (Fig. 3A ); 2D + 2S, paralectotypes of " Amphidromus ingens ", SMF 7566/4 (Fig. 3B ). Vietnam : Dextral, holotype of " Amphidromus naggsi ", RMNH.5003908 (Fig. 3C ) . Figure 3. Shells of Amphidromus ingens Moellendorff , 1900 A lectotype of " Amphidromus ingens " (SMF 7565) B paralectotype of " Amphidromus ingens " (SMF 7566) C holotype of " Amphidromus naggsi " (RMNH.5003908) D, E specimens from M'drak , Dak Lak , Vietnam (NMNS-8764-082, NMNS-8764-084) F specimen from Ea M'doal , M'drak , Dak Lak , Vietnam (NMNS-8764-087) G specimen from Krong A, M'drak , Dak Lak , Vietnam (NMNS-8764-088) H, I specimens from Ea Sup, Dak Lak , Vietnam (NMNS-8764-093, NMNS-8764-101). Credit: J. Goud, RMNH ( C ). Other material examined. Vietnam : 4D + 1S specimens, M'drak District, Dak Lak Province , NMNS-8764-082- NMNS-8764-086 (Fig. 3D, E ); 1D specimen, Ea M'doal ward, M'drak District, Dak Lak Province , NMNS-8764-087 (Fig. 3F ); 4D + 1S specimens, Krong A ward, M'drak District, Dak Lak Province , NMNS-8764-088- NMNS-8764-092 (Fig. 3G ); 7D + 5S specimens, Ea Sup District , Dak Lak Province , NMNS-8764-093- NMNS-8764-104 (Fig. 3H, I ) . Diagnosis. Shell large conical and chirally dimorphic (sinistral and dextral coiling). Shell surface with coarse growth lines; last whorl with subsutural depression area and more or less prominent keel on periphery. Genitalia with appendix. Differential diagnosis. Amphidromus ingens is unique among all reported Vietnamese species ( Schileyko 2011 ) in having a last whorl with subsutural depression area and more or less prominent keel on periphery. Amphidromus bozhii is similar in most of the shell form and sculpture, but the shell sculpture of A. bozhii has a very weak spiral depression area and sometimes with or without keel, and the shell colour is generally rose-pink to dark colour, with last whorl stained with dark brown colour below periphery and ~ 1/2 of upper periphery. On the other hand, A. ingens has a monochrome (whitish, yellowish, tinted pink) shell, often stained with dark brown to blackish below periphery. Amphidromus ingens is also recognised by a distinct clade in the molecular phylogeny (Fig. 2 ), with the closest p -distance to A. ingensoides sp. nov. in COI (10.2%) and A. bozhii in 16S (2.76%) (Table 2 ). Description. Shell large (height 62.3-74.6 mm, width 38.5-42.5 mm), chirally dimorphic, solid, and ovate conical shape. Spire long conical to elongate conical, apex acute without black spot on tip. Whorls 5-7 convex; suture wide and depressed; last whorl rounded to slightly angulated. Periostracum brownish to thin corneous; varix usually absent. Shell surface generally with irregular and coarse growth lines; below sutural with broad subsutural depression area, and with blunt or low to prominent keel on periphery. Shell colour highly variable: monochrome (whitish, yellowish, tinted pink) to stained with dark brown to blackish below periphery. Parietal callus thickened and white, dilated at umbilical area. Aperture broadly ovate; inner side of outer wall with white, yellow or dark brown to blackish colour. Peristome thickened, expanded, and reflexed but not attached to last whorl; lip whitish. Columella white, straight, or little twisted. Umbilicus imperforate. Radula . Teeth arranged in anteriorly pointed V-shaped rows. Central tooth monocuspid and spatulate with truncated cusp. Lateral teeth bicuspid; endocone small, slightly curved, with wide notch and dull cusp; ectocone large with truncated to slightly curved cusp. Lateral teeth gradually transformed to asymmetric tricuspid marginal teeth (Fig. 4A ). Figure 4. SEM images of the radula of Amphidromus spp A Amphidromus ingens Moellendorff , 1900 from Ea Sup, Dak Lak, Vietnam (NMNS-8764-100) B Amphidromus asperoides sp. nov. from Ea Tu, Buon Ma Thuat city, Dak Lak, Vietnam (NMNS-8764-001) C Amphidromus bozhii Wang, 2019 from Tuy Hoa, Phu Yen, Vietnam (NMNS-8764-016). Central teeth are marked in yellow. The left and right images show the outer and inner sections of each radula, respectively. Genital organs . Atrium relatively short. Penis slender, conical, and short ~ 1/3 of vaginal length. Penial retractor muscle thickened and inserting on epiphallus close to penis. Epiphallus long, slender tube, slightly narrower than penis. Flagellum short ~ 1/2 of epiphallus and terminating in slightly enlarged folded coil. Appendix short, slender tube, approximately as long as epiphallus, and ~ 2 x longer than flagellum. Vas deferens slender tube passing from free oviduct and terminating at epiphallus-flagellum junction (Fig. 5A ). Internal wall of penis corrugated, exhibiting series of thickened and swollen longitudinal penial pilasters forming fringe around penial wall, and with nearly smooth to weak folds around base of penial verge. Penial verge short conical with nearly smooth surface, and with opening on the tip (Fig. 5B ). Figure 5. Genitalia of Amphidromus spp A-C Amphidromus ingens Moellendorff , 1900 from Ea Sup, Dak Lak, Vietnam (NMNS-8764-100), showing A general view of genitalia B interior structures of penis C interior structures of vagina chamber and gametolytic duct D-F Amphidromus asperoides sp. nov. from Ea Tu, Buon Ma Thuat city, Dak Lak, Vietnam (NMNS-8764-001), showing D general view of genitalia E interior structures of penis F interior structures of 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; ov, oviduct; p, penis; pp, penial pilaster; pr, penial retractor muscle; pv, penial verge; v, vagina; vd, vas deferens; vp, vaginal pilaster Vagina slender, long cylindrical, and ~ 3 x longer than penis. Gametolytic duct enlarged cylindrical tube then abruptly tapering to slender tube terminally and connected to gametolytic sac (missing during dissecting). Free oviduct short; oviduct compact and enlarged to form lobule alveoli (Fig. 5A ). Internal wall of vagina possessing corrugated ridges near genital orifice; ridges becoming thinner and smooth surfaced longitudinal vaginal pilasters, swollen with irregularly shaped and deep crenelations close to free oviduct opening. Spermatophore (in part) dark brown stuck inside gametolytic duct (Fig. 5C ). Living specimens generally with pale brown to yellowish body covered with reticulated skin. Foot broad and long with uniform pale brownish to yellowish colour to posterior tail. Dorsal side of anterior body usually with stripe of darkly reticulated skin; head area at base and just behind upper tentacle with orange patch. Upper tentacles drumstick shaped, orange to paler and with dark eyespots on tentacular tips; lower tentacles short and pale orange in colour (Fig. 6A-C ). Figure 6. Living Amphidromus spp A-C Amphidromus ingens Moellendorff , 1900 from Dak Lak, Vietnam D Amphidromus placostylus Moellendorff , 1900 from Hoai An, An Lao, Binh Dinh, Vietnam E, F Amphidromus ingensoides sp. nov. from Hon Ba, Khanh Son, Khanh Hoa, Vietnam G Amphidromus asperoides sp. nov. from Ea Tu, Buon Ma Thuat city, Dak Lak, Vietnam H, I Amphidromus buelowi Fruhstorfer, 1905 from Lang-Biang plateau, Lac Duong, Lam Dong, Vietnam J Amphidromus thachi Huber, 2015 from Krong Bong, Dak Lak, Vietnam. Haplotype network. There was a total of 12 COI haplotypes (Fig. 7A ) and nine 16S haplotypes (Fig. 7B ) of A. ingens in this study, and the highest numbers of mutational steps in the COI and 16S minimum spanning networks are 13 and three, respectively. Figure 7. Mitochondrial haplotype minimum spanning networks of Amphidromus ingens Moellendorff , 1900 A COI and B 16S rRNA. 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 . Distribution. The distribution range of the species covers Dak Lak and Lam Dong provinces, Vietnam. Remarks. Thach and Huber (2014) introduced A. naggsi , which is described to differ from A. ingens in its wrinkled outer surface, the presence of 2-3 broad spiral channels on the body whorl, the more prominent sculpture on the penultimate whorl, and a more elongate aperture. However, upon examining the type specimens of both A. ingens and A. naggsi , these diagnostic characters were also present in the lectotype and paralectotypes of A. ingens , and the holotype of A. naggsi agrees well with all the type specimens of A. ingens in terms of shell shape, shell surface sculpture, peristome, and apertural shape. Thus, A. naggsi is regarded herein as a junior subjective synonym of A. ingens . The shell colour generally varies from whitish (typical) to yellowish to rose-pink colour (Fig. 3 ). In our examined specimens, many are stained with dark brown colour below periphery and some are stained nearly entirely on the last and penultimate whorl. The shell sculpture generally has two depression areas, one upper periphery and one below suture, and the conspicuous keel to weak keel is generally present on periphery.