Research Article |
Corresponding author: Chirasak Sutcharit ( jirasak4@yahoo.com ) Corresponding author: Chi-Tse Lee ( leechitse@yahoo.com.tw ) Academic editor: Thierry Backeljau
© 2024 Parin Jirapatrasilp, Chih-Wei Huang, Chirasak Sutcharit, Chi-Tse Lee.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Jirapatrasilp P, Huang C-W, Sutcharit C, Lee C-T (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: 15-78. https://doi.org/10.3897/zookeys.1196.112146
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This paper reassesses the taxonomy and systematics of 11 arboreal snail species in the genus Amphidromus from Vietnam, Cambodia, Indonesia and Laos (A. bozhii Wang, 2019, A. buelowi Fruhstorfer, 1905, A. costifer Smith, 1893, A. haematostoma Möllendorff, 1898, A. ingens Möllendorff, 1900, A. madelineae Thach, 2020, A. metabletus Möllendorff, 1900, A. pankowskianus Thach, 2020, A. placostylus Möllendorff, 1900, A. roseolabiatus Fulton, 1896, and A. thachi Huber, 2015). The taxonomic validity of each species is supported by a phylogenetic analysis of mitochondrial COI and 16S rRNA gene fragments from 17 ingroup taxa. Amphidromus buelowi was found to comprise two populations from two distant localities, one from Mount Singgalang, West Sumatra, Indonesia and the other from southern Vietnam. The samples from southern Vietnam were previously described as A. asper Haas, 1934 and A. franzhuberi Thach, 2016, but they are now treated as junior synonyms of A. buelowi in this study. In addition, two species from Vietnam are described as new to science, viz. A. asperoides Jirapatrasilp & Lee, sp. nov. and A. ingensoides Jirapatrasilp & Lee, sp. nov., each of which is conchologically comparable to A. buelowi and A. ingens, respectively.
Biodiversity, Helicoidei, shell polymorphism, Stylommatophora, taxonomy
Since the comprehensive synoptic catalogue of the Southeast Asian arboreal snail genus Amphidromus Albers, 1850 by
This paper is the first of a series that aims to revise the taxonomy and systematics of Amphidromus species from Southeast Asia, following the taxonomic reassessment of A. cruentatus (Morelet, 1875) in
Against this background, new specimens of these 11 nominal species were collected in order to study their shell and anatomical characters, compare them with the available type material of species known from the study area, and to infer their phylogenetic relationships using DNA sequence data.
Empty shells and living specimens were collected from several localities in Cambodia, Indonesia, Laos, and Vietnam (Fig.
Distribution map of Amphidromus samples recognised in this study. 1. Amphidromus bozhii; 2. Amphidromus placostylus; 3. Amphidromus asperoides sp. nov.; 4. Amphidromus ingens; 5. Amphidromus ingensoides sp. nov.; 6. Amphidromus buelowi; 7. Amphidromus thachi; 8. Amphidromus metabletus; 9. Amphidromus haematostoma; 10. Amphidromus madelineae; 11. Amphidromus costifer; 12. Amphidromus pankowskianus; 13. Amphidromus roseolabiatus. Species numbers correspond to those in Fig.
List of specimens used in this study with species name, locality details, voucher and GenBank accession numbers. Species numbers correspond to those in Figs
Number | Species | Preliminary species identification in this study | Specimen codes | Voucher numbers | Locality | No. of specimen and chirality | Figure | GenBank accession numbers | References | |
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COI | 16S rRNA | |||||||||
1 | Amphidromus bozhii Wang, 2019 | A. bozhii | XI0 to XI9 | NMNS-8764-004 to NMNS-8764-013 | Phu Hoa District, Phu Yen Province, Vietnam | 10D | 8D–E | XI0–XI8: OR977987–OR977995 | XI0–XI2: OR964283– OR964285 XI5: OR964286 | This study |
A. bozhii | XJ1 to XJ8 | NMNS-8764-014 to NMNS-8764-021 | Tuy Hoa District, Phu Yen Province, Vietnam | 8S | 8F | XJ1–XJ8: OR977996–OR978003 | – | |||
2 | Amphidromus placostylus Möllendorff, 1900 | A. placostylus | VAM0 to VAM4 | NMNS-8764-213 to NMNS-8764-217 | Dak Po District, Gia Lai Province, Vietnam | 4D + 1S | 11C–D | VAM1–VAM4: OR978004– OR978007 | VAM1–VAM4: OR964287– OR964290 | This study |
A. placostylus | VKAA1 to VKAA4 | NMNS-8764-218 to NMNS-8764-221 | Kbang, Gia Lai Province, Vietnam | 3D + 1S | 11E–F | VKAA2–VKAA4: OR978008– OR978010 | VKAA2–VKAA4: OR964291– OR964293 | |||
A. placostylus | VKBB0 to VKBB9 | NMNS-8764-222 to NMNS-8764-231 | Hoai An, An Lao, Binh Dinh Province, Vietnam | 4D + 6S | 11G–I | VKBB0: OR978011 VKBB5: OR978012 VKBB9: OR978013 | VKBB0: OR964294 VKBB5: OR964295 VKBB9: OR964296 | |||
A. placostylus | VKBN | NMNS-8764-232 | Binh Dinh Province, Vietnam | 1D | – | – | – | |||
A. placostylus | VMEO1 to VMEO21 | NMNS-8764-233 to NMNS-8764-253 | Hoai An district, Binh Dinh Province, Vietnam | 7D + 14S | – | – | – | |||
3 | Amphidromus asperoides Jirapatrasilp & Lee sp. nov. | Amphidromus sp. 1 | D2-1 to D2-4 | NMNS-8764-001 to NMNS-8764-003, NHMUK 20230613 | Ea Tu village, Buon Ma Thuat city, Dak Lak Province, Vietnam | 4D | 8A–C | OR978014– OR978017 | OR964297– OR964300 | This study |
Amphidromus sp. 1 | VTAU1 to VTAU20 | NMNS-8764-192 to NMNS-8764-211 | Krong Pak, Dak Lak Province, Vietnam | 20D | – | – | – | |||
4 | Amphidromus ingens Möllendorff, 1900 | A. ingens | G3-1 to G3-5 | NMNS-8764-082 to NMNS-8764-086 | M’drak District, Dak Lak Province, Vietnam | 4D + 1S | 3D–E | G3-1: OR978018 | – | This study |
A. ingens | R50 | NMNS-8764-087 | Ea M’doal Ward, M’drak District, Dak Lak Province, Vietnam | 1D | 3F | OR978019 | OR964301 | |||
A. ingens | U20 to U24 | NMNS-8764-088 to NMNS-8764-092 | Krong A Ward, M’drak District, Dak Lak Province, Vietnam | 4D + 1S | 3G | U20–U23: OR978020– OR978023 | OR964302– OR964306 | |||
A. ingens | YD1 to YD8, YE1 to YE4 | NMNS-8764-093 to NMNS-8764-104 | Ea Sup District, Dak Lak Province, Vietnam | 7D + 5S | 3H–I | YD1–YD8: OR978024– OR978031 YE1–YE4: OR978032– OR978035 | YD1–YD2: OR964307– OR964308 YD5–8: OR964309– OR964312 YE1–YE4: OR964313– OR964316 | |||
5 | Amphidromus ingensoides Jirapatrasilp & Lee sp. nov. | Amphidromus sp. 2 | G4, P6 | NHMUK 20230614, NMNS-8764-105 | CuMta Ward, M’drak District, Dak Lak Province, Vietnam | 1D + 1S | 8G–H | OR978036– OR978037 | OR964317– OR964318 | This study |
Amphidromus sp. 2 | U10, U11 | NMNS-8764-106, NMNS-8764-107 | Hon Ba, Khanh Son District, Khanh Hoa Province, Vietnam | 1D + 1S | 8I–J | OR978038– OR978039 | OR964319– OR964320 | |||
6 | Amphidromus buelowi Fruhstorfer, 1905 | A. buelowi | SUK1 to SUK4 | NMNS-8764-022 to NMNS-8764-025 | Mount Singgalang, Sepuluh Koto, Tanah Datar Regency, West Sumatra, Indonesia | 4D | 15E | SUK2–SUK3: OR978040– OR978041 | SUK2–SUK3: OR964321– OR964322 | This study |
A. asper | VCF, VCI7 | NMNS-8764-026, NMNS-8764-027 | Lang-Biang plateau, Lac Duong District, Lam Dong Province, Vietnam | 2D | 15G | VCF: OR978042 | VCF: OR964323 | |||
A. franzhuberi | VCG, VCI1 to VCI6 | NMNS-8764-028 to NMNS-8764-034 | Nha Trang, Khanh Hoa Province, Vietnam | 6D + 1S | 15H–I | VCG: OR978043 VCI1–VCI3: OR978044–OR978046 | VCG: OR964324 VCI1–VCI3: OR964325– OR964327 | |||
7 | Amphidromus thachi Huber, 2015 | A. thachi | VBQ1, VBQ2 | NMNS-8764-264, NMNS-8764-265 | Lac Duong District, Lam Dong Province, Vietnam | 2D | 17G–H | OR978048– OR978049 | OR964329– OR964330 | This study |
A. thachi | VBI1 to VBI4 | NMNS-8764-266 to NMNS-8764-269 | Vinh Thanh, Binh Dinh Province, Vietnam | 3D + 1S | 17D | VBI1: OR978047 | VBI1: OR964328 | |||
A. thachi | VCD1, VCD2 | NMNS-8764-270, NMNS-8764-271 | Buon Don District, Dak Lak Province, Vietnam | 1D + 1S | 17E | OR978050– OR978051 | OR964331– OR964332 | |||
A. thachi | VMAM | NMNS-8764-272 | Da Lat, Lam Dong Province, Vietnam | 1S | 17F | OR978052 | OR964333 | |||
A. thachi | XM1, XM2 | NMNS-8764-273, NMNS-8764-274 | Krong Bong, Dak Lak Province, Vietnam | 2D | – | OR978053– OR978054 | OR964334– OR964335 | |||
8 | Amphidromus metabletus Möllendorff, 1900 | A. metabletus | P3 to P5, XE1 to XE5 | NMNS-8764-123 to NMNS-8764-130 | Nha Trang, Khanh Hoa Province, Vietnam | 4D + 4S | 21C–F | P3–P5: OR978055– OR978057 XE1–XE5: OR978064– OR978068 | P3–P5: OR964336– OR964338 XE1–XE5: OR964344–OR964348 | This study |
A. metabletus | VMELa1 to VMELa6, VMELb1 to VMELb6, VMELc1, VMELd1 to VMELd3, VMELe1 to VMELe3 | NMNS-8764-131 to NMNS-8764-149 | Ninh Hoa, Khanh Hoa Province, Vietnam | 15D + 4S | 21G–L | VMELa6: OR978058 VMELb6: OR978059 VMELc1: OR978060 VMELd1: OR978061 VMELd3: OR978062 VMELe1: OR978063 | VMELa6: OR964339 VMELb6: OR964340 VMELc1: OR964341 VMELd1: OR964342 VMELe1: OR964343 | |||
9 | Amphidromus haematostoma Möllendorff, 1898 | A. haematostoma | X91 to X94 | NMNS-8764-053 to NMNS-8764-056 | Samphanh District, Phongsali Province, Laos | 4S | 24D | – | X92–X94: OR964349– OR964351 | This study |
A. haematostoma | ZK0 to ZK9, ZK9a to ZJ9j | NMNS-8764-057 to NMNS-8764-076 | Ba Chien, Pakse District, Champasak Province, Laos | 20S | 24E–F | ZK6–ZK7: OR978073– OR978074 ZK9: OR978075 | ZK6–ZK7: OR964352– OR964353 | |||
A. haematostoma | AM36 | ex. Maassen collection | Boloven Plateau, Paksong District, Champasak Province, Laos | 1S | – | OR978069 | – | |||
A. haematostoma | VMDO1 to VMDO5 | NMNS-8764-077 to NMNS-8764-081 | Kbang District, Gia Lai Province, Vietnam | 5S | 24G | VMDO1: OR978070 VMDO4: OR978071 VMDO5: OR978072 | – | |||
10 | Amphidromus madelineae Thach, 2020 | A. madelineae | VBO1 to VBO5 | NMNS-8764-108 to NMNS-8764-112 | Duy Xuyen District, Quang Nam Province, Vietnam | 5S | 24I–J | VBO2: OR978076 VBO5: OR978077 | VBO2: OR964354 VBO5: OR964355 | This study |
A. madelineae | VKBG0 to VKBG9 | NMNS-8764-113 to NMNS-8764-122 | Za Hung, Dong Giang District, Quang Nam Province, Vietnam | 10S | 24K–M | VKBG1: OR978078 VKBG5: OR978079 VKBG9: OR978080 | VKBG1: OR964356 VKBG5: OR964357 VKBG9: OR964358 | |||
11 | Amphidromus costifer Smith, 1893 | A. costifer | YW0 to YW9 | NMNS-8764-035 to NMNS-8764-044 | Tay Son District, Binh Dinh Province, Vietnam | 10D | 27D–E | – | YW0–YW8: OR964366– OR964374 | This study |
A. costifer | YF1 to YF6 | NMNS-8764-045 to NMNS-8764-050 | Ea Sup District, Dak Lak Province, Vietnam | 6D | 27F–G | YF4: OR978083 | YF2–YF6: OR964361– OR964365 | |||
A. nguyenkhoai | VKBE1, VKBE2 | NMNS-8764-051, NMNS-8764-052 | An Lao District, Binh Dinh Province, Vietnam | 2D | 27H–I | OR978081– OR978082 | OR964359– OR964360 | |||
12 | Amphidromus pankowskianus Thach, 2020 | A. pankowskianus | CAF1 to CAF3 | NMNS-8764-150 to NMNS-8764-152 | Khammouan Province, Laos, near Minh Hoa District, Quang Binh Province, Vietnam | 2D + 1S | 30K–L | CAF1–CAF2: OR978084– OR978085 | CAF1: OR964375 | This study |
A. pankowskianus | VTAR1 to VTAR40 | NMNS-8764-153 to NMNS-8764-191, NMNS-8764-212 | Lak Sao, Khamkeut District, Bolikhamsai Province, Laos | 23D + 17S | 30H–J | VTAR02: OR978086 VTAR06: OR978087 VTAR08–VTAR09: OR978088–OR978089 VTAR11: OR978090 VTAR15: OR978091 | – | |||
13 | Amphidromus roseolabiatus Fulton, 1896 | A. roseolabiatus | CAB0 to CAB9 | NMNS-8764-254 to NMNS-8764-263 | Kambong Siem District, Kampong Cham Province, Cambodia | 4D + 6S | 30D–F | CAB0: OR978092 CAB2–CAB3: OR978093– OR978094 CAB7: OR978095 | CAB0: OR964376 CAB2–CAB3: OR964377– OR964378 CAB7: OR964379 | This study |
14 | Amphidromus cruentatus (Morelet, 1875) | X71 to X79, X81 to X88 | NMNS-8476-001 to NMNS-8476-009, NMNS-8476-034 to NMNS-8476-041 | Samphanh District, Phongsali Province, Laos | 17S | – | OL352241–OL352248, OL352249–OL352255 | X71: OL352062 X73–X79: OL352063–OL352069 X81–X88: OL352070–OL352077 |
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ZY3, ZY4, ZY7 | NMNS-8476-054, NMNS-8476-055, NMNS-8476-058 | Chu Prong District, Gia Lai Province, Vietnam | 3S | – | OL352256–OL352258 | ZY3–ZY4: OL352078–OL352079 ZY7: OL352080 | ||||
15 | Amphidromus contrarius (Müller, 1774) | AM C.468733 | – | 6.5 km N of Los Palos, Lautem District, Timor-Leste | 1S | – | KP085341 | KP085031 |
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16 | Amphidromus perversus (Linnaeus, 1758) | AM19 | CUMZ 4291 | Bali Island, Indonesia | 1S | – | MW649970 | MW652850 |
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17 | Amphidromus sinistralis (Reeve, 1849) | AM38 | ex. Maassen collection | Sulawesi, Indonesia | 1S | – | OR978096 | – | This study | |
Outgroup | ||||||||||
18 | Camaena cicatricosa (Müller, 1774) | FJIQBC18503 | – | Guiping, Guangxi, China | – | – | KU061276 | KU586474 |
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19 | Camaena poyuensis Zhou, Wang & Ding, 2016 | FJIQBC18484 | – | Poyue town, Bama, Hechi, Guangxi, China | – | – | KU061273 | KU586468 |
Preliminary morphospecies identifications were based on (1) the shell characters used in the original descriptions and other relevant literature, such as
The acquisition of new DNA data of both mitochondrial COI and 16S rRNA, and molecular phylogenetic analyses including the calculation of intra- and interspecific p-distances and constructions of phylogenetic trees and haplotype networks, follow
The sequence alignments of each gene fragment were performed separately using MAFFT (v. 7, see https://mafft.cbrc.jp/alignment/server/index.html), with default options (
In addition, a maximum likelihood (ML) tree was constructed using the IQ-TREE webserver (see http://iqtree.cibiv.univie.ac.at), with integrated ModelFinder function (
Uncorrected pairwise genetic distances (p-distances) among different Amphidromus species were calculated in MEGA (v. 7.0, see https://www.megasoftware.net/) using pairwise deletion (
Preliminary morphospecies identifications were validated by the reciprocal monophyly of each morphospecies in the phylogeny constructed from the concatenated COI + 16S dataset. We adopted the interspecific COI genetic distance of 4%, which has been associated with the optimum intra/interspecific threshold value for stylommatophoran land snails (
The abbreviations D (dextral) and S (sinistral) are used in conjunction with numbers of specimens in the material examined sections of each species. Abbreviations for the gential organs in the figure captions follow those defined by
The COI dataset of Amphidromus in this study comprised 130 sequences with lengths between 556 and 658 bp, including 284 variable and 265 parsimony-informative sites, from an alignment length of 658 bp. The variation in the COI sequence lengths is due to incomplete sequences at both ends in some sequences. The 16S rRNA dataset comprised 118 sequences with lengths between 343 and 394 bp. The 16S rRNA alignment including gaps was 414 bp, including 136 variable and 125 parsimony-informative sites.
The ML and BI phylogenetic analyses based on the concatenated datasets yielded consistent topologies (Fig.
Bayesian phylogeny of Amphidromus spp. based on mitochondrial COI and 16S 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.
The DNA sequence data show that the phylogenetic relationships among the species did not mirror their geographical ties. Amphidromus contrarius, A. perversus, and A. sinistralis each did not belong to the same clades of the other taxa, and the relationships of these three species with other species remain unresolved. Amphidromus roseolabiatus and A. pankowskianus were retrieved together as sister clades forming a distinct well-supported clade (SH-aLRT ≥ 80%, aBayes ≥ 0.95, BS ≥ 95%, PP ≥ 0.95) separate from the clade with the remaining taxa. These latter were grouped in a well-supported clade, with A. costifer as a sister taxon to all other species in this clade. Amphidromus cruentatus, A. haematostoma, and A. madelineae were closely related in that A. cruentatus was sister to the clade A. haematostoma + A. madelineae. The remaining taxa belonged to a well-supported clade, where A. bozhii, A. ingens, A. placostylus, as well as the two new species belonged to the same well-supported subclade. Amphidromus bozhii was sister to A. placostylus, and A. asperoides sp. nov. was sister to A. ingens.
The COI p-distances ranged from 0 to 10.03% (average 2.78 ± 3.04%) within species and from 9.61 to 24.16% (average 18.30 ± 3.35%) between species (Table
Percentage of uncorrected pairwise interspecific distances for the partial COI (above the diagonal) and 16S rRNA (below the diagonal) gene fragments among the Amphidromus species in this study. Intraspecific distances for COI/16S rRNA are shown on the diagonal (bold). Species numbers correspond to those in Figs
Species | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 |
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1. A. bozhii (n = 17, 4) | 0.60/ 0.13 | 9.61 | 10.33 | 10.82 | 9.99 | 13.29 | 13.04 | 17.30 | 19.19 | 18.25 | 18.88 | 18.87 | 17.94 | 21.40 | 22.36 | 18.97 | 18.85 |
2. A. placostylus (n = 10, 10) | 4.32 | 5.47/ 3.14 | 9.83 | 10.51 | 10.53 | 12.79 | 13.04 | 16.57 | 19.02 | 18.44 | 17.89 | 19.60 | 18.11 | 21.09 | 22.16 | 19.74 | 19.75 |
3. A. asperoides sp. nov. (n = 4, 4) | 3.31 | 4.68 | 0/0 | 10.32 | 10.69 | 13.13 | 12.69 | 16.72 | 18.47 | 18.02 | 17.12 | 20.33 | 18.78 | 20.76 | 22.41 | 18.45 | 18.29 |
4. A. ingens (n = 18, 16) | 2.76 | 4.23 | 3.02 | 1.37/ 0.52 | 10.20 | 12.23 | 12.74 | 15.91 | 19.12 | 18.38 | 17.06 | 20.01 | 18.26 | 20.65 | 20.71 | 17.71 | 20.01 |
5. A. ingensoides sp. nov. (n = 4, 4) | 4.25 | 5.14 | 4.61 | 4.19 | 3.32/ 1.45 | 13.51 | 12.80 | 16.27 | 19.16 | 19.48 | 17.63 | 19.98 | 19.20 | 21.76 | 21.62 | 18.18 | 19.23 |
6. A. buelowi (n = 7, 7) | 5.00 | 5.60 | 4.61 | 4.61 | 4.89 | 1.25/ 0.19 | 13.40 | 17.05 | 18.72 | 18.79 | 18.47 | 20.63 | 18.32 | 21.01 | 21.78 | 18.75 | 19.04 |
7. A. thachi (n = 8, 8) | 7.41 | 8.21 | 6.22 | 7.19 | 6.90 | 6.36 | 2.21/ 1.07 | 16.32 | 19.81 | 19.43 | 16.81 | 19.67 | 18.31 | 20.81 | 21.03 | 18.05 | 19.28 |
8. A. metabletus (n = 14, 13) | 11.08 | 12.11 | 11.67 | 12.04 | 10.84 | 11.40 | 10.68 | 1.28/ 0.58 | 20.40 | 19.43 | 16.63 | 20.47 | 18.53 | 20.56 | 21.53 | 18.30 | 19.25 |
9. A. haematostoma (n = 7, 5) | 10.53 | 10.80 | 10.10 | 9.59 | 9.66 | 9.38 | 10.52 | 12.59 | 10.03/ 1.99 | 13.93 | 20.61 | 22.44 | 21.43 | 20.76 | 23.28 | 21.39 | 21.74 |
10. A. madelineae (n = 5, 5) | 9.71 | 9.89 | 9.17 | 8.10 | 8.78 | 9.26 | 9.66 | 11.63 | 6.04 | 2.19/ 0.33 | 17.81 | 21.12 | 19.61 | 20.26 | 22.90 | 21.62 | 20.60 |
11. A. costifer (n = 3, 16) | 15.45 | 15.56 | 14.85 | 15.33 | 14.91 | 13.44 | 13.69 | 14.41 | 16.00 | 16.02 | 7.84/ 3.39 | 19.53 | 19.31 | 20.38 | 21.73 | 20.23 | 18.90 |
12. A. pankowskianus (n = 8, 1) | 13.72 | 14.18 | 14.20 | 13.44 | 13.61 | 12.50 | 14.31 | 13.78 | 14.01 | 13.15 | 14.37 | 0.19/NA | 13.02 | 20.49 | 21.57 | 19.59 | 20.38 |
13. A. roseolabiatus (n = 4, 4) | 14.28 | 14.21 | 13.91 | 14.09 | 15.10 | 13.23 | 13.03 | 15.51 | 14.56 | 13.08 | 15.31 | 6.14 | 0/0 | 20.16 | 21.93 | 18.97 | 19.08 |
14. A. cruentatus (n = 18, 19) | 10.17 | 9.93 | 10.82 | 9.71 | 9.90 | 10.26 | 11.11 | 12.04 | 11.37 | 12.17 | 15.39 | 14.21 | 15.63 | 3.15/ 1.17 | 24.16 | 20.13 | 21.37 |
15. A. contrarius (n = 1, 1) | 15.62 | 16.12 | 15.90 | 16.04 | 15.56 | 15.41 | 15.57 | 16.74 | 16.41 | 15.16 | 14.91 | 14.29 | 14.91 | 16.11 | NA/NA | 21.65 | 21.95 |
16. A. perversus (n = 1, 1) | 13.75 | 14.08 | 14.00 | 13.44 | 14.51 | 14.70 | 14.93 | 16.18 | 15.89 | 13.09 | 13.86 | 13.61 | 13.09 | 15.46 | 13.45 | NA/NA | 18.29 |
17. A. sinistralis (n = 1, 0) | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA/NA |
Comparable patterns were observed for 16S, the p-distances of which ranged from 0 to 3.39% (average 1.07 ± 1.14%) within species and from 2.76–16.74% (average 11.68 ± 3.79%) between species (Table
Family Camaenidae Pilsbry, 1895
Amphidromus
Albers, 1850: 138. Martens in
Helix perversus Linnaeus, 1758 by subsequent designation of E. von Martens in
Amphidromus ingens
Möllendorff, 1900b: 23–24. Type locality: Berg “Mutter und Kind”, Annam [Vietnam].
Amphidromus (Amphidromus) ingens.
Amphidromus naggsi
Thach & Huber, 2014: 35–37, figs 1–13, 15. Type locality: Don Duong district, Lam Dong Province, South Vietnam.
Vietnam: Dextral, lectotype of “Amphidromus ingens”,
Shells of Amphidromus ingens Möllendorff, 1900 A lectotype of “Amphidromus ingens” (
Vietnam: 4D + 1S specimens, M’drak District, Dak Lak Province,
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.
Amphidromus ingens is unique among all reported Vietnamese species (
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.
SEM images of the radula of Amphidromus spp A Amphidromus ingens Möllendorff, 1900 from Ea Sup, Dak Lak, Vietnam (
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× longer than flagellum. Vas deferens slender tube passing from free oviduct and terminating at epiphallus-flagellum junction (Fig.
Genitalia of Amphidromus spp A–C Amphidromus ingens Möllendorff, 1900 from Ea Sup, Dak Lak, Vietnam (
Vagina slender, long cylindrical, and ~ 3× 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.
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.
Living Amphidromus spp A–C Amphidromus ingens Möllendorff, 1900 from Dak Lak, Vietnam D Amphidromus placostylus Möllendorff, 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.
There was a total of 12 COI haplotypes (Fig.
Mitochondrial haplotype minimum spanning networks of Amphidromus ingens Möllendorff, 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
The distribution range of the species covers Dak Lak and Lam Dong provinces, Vietnam.
The shell colour generally varies from whitish (typical) to yellowish to rose-pink colour (Fig.
Amphidromus asper
[non Haas].
Shell large conical and dextral. Shell colour with dark triangular blotches connected with dark zigzag radial streaks. Aperture ovate and rounded anteriorly, columella straight. Genitalia with appendix.
The new species differs from the similar species A. buelowi in being exclusively dextral, having a straight columella, and lacking an apertural notch and umbilical hump. In contrast, A. buelowi is chirally dimorphic, and possesses a distinct twisted columella plait, a prominent umbilical hump encircled columellar area, and an apertural notch projecting anteriorly. In addition, on the soft body of living snail, A. asperoides sp. nov. has a uniform brownish yellow to pale brown of the entire body, while A. buelowi exhibits a reddish orange body. This new species is also recognised as a distinct clade in the molecular phylogeny (Fig.
The specific epithet asperoides is from asper, and the suffix ‘–oideus’, meaning ‘like or resembling’. This name refers to the resemblance in shell morphology of the new species to the nominal species A. asper, which is now treated as a junior synonym of A. buelowi.
Holotype. Vietnam: dextral, shell height 61.7 mm, shell width 34.9 mm, with 7 whorls, 15 July 2016, coll. A. N. Pham (
Shells of Amphidromus spp A–C Amphidromus asperoides sp. nov. from Ea Tu, Buon Ma Thuat city, Dak Lak, Vietnam A holotype (
Vietnam: Ea Tu village, Buon Ma Thuat city, Dak Lak Province, 12°42'24.4"N, 108°07'25.3"E.
Vietnam: 20D specimens, Krong Pak, Dak Lak Province,
Shell large (height 54.6–61.7 mm, width 31.3–34.9 mm), dextral, solid, and ovate conical shape. Spire long conical with white or pale colour; apex acute without black spot on tip. Whorls 6–7 convex; suture wide and depressed; last whorl ovate. Periostracum thin corneous; varices generally present. Shell surface generally with coarse growth lines. Shell ground colour pale pink, decorated with dark triangular blotches connected with dark zigzag radial streaks. Parietal callus thickened, slightly opaque, white and much thinner in central area. Aperture ovate; without (or very weak) anterior notch and umbilical hump; inner side of outer wall whitish colour; peristome thickened, expanded, and reflexed but not attached to last whorl; lip whitish. Columella white, straight, or weakly 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, with shallow notch and blunt cusp; ectocone large with curved cusp. Lateral teeth gradually transformed to asymmetric tricuspid marginal teeth (Fig.
Genital organs. Atrium relatively short. Penis slender, conical, and short ~ 1/4 of vaginal length. Penial retractor muscle thickened, long and inserting on epiphallus near penis. Epiphallus very long ~ 2× longer than vagina, and slender tube. Flagellum short, extending from epiphallus and terminating in slightly enlarged tube. Appendix short and slender tube, 4×longer than flagellum and approximately as long as epiphallus. Vas deferens slender tube passing from free oviduct and terminating at epiphallus-flagellum junction (Fig.
Vagina long, slender, cylindrical, and ~ 2× longer than penis. Gametolytic duct enlarged cylindrical tube then abruptly tapering to slender tube terminally and connected to gametolytic sac (missing during dissection). Free oviduct short; oviduct compact, enlarged to form lobule alveoli (Fig.
Living specimens
with soft body morphology generally similar to A. ingens. Animals with uniform brownish yellow to pale brown of the entire body including foot, upper and lower tentacles (Fig.
This species is known from Dak Lak Province, Vietnam.
This new species had been previously identified as A. asper in
Amphidromus bozhii Wang, 2019: 300–301, pl. 3, figs a, b. Type locality: Phu Yen Province, Vietnam.
Vietnam: 10D specimens, Phu Hoa District, Phu Yen Province,
Shell large conical and chirally dimorphic. Shell surface with coarse growth lines; last whorl nearly absent of spiral depression area and keel. Genitalia with appendix.
This species is similar to A. ingens in most of the shell form and sculpture. The distinguishing characters are the shell colour which is generally rose-pink to dark colour. The last whorl is stained with dark brown colour below periphery and ~ 1/2 of upper periphery. The shell sculpture has a very weak spiral depression area and sometimes with or without keel. This species looks like an intermediate form between A. ingens and A. placostylus. Amphidromus bozhii is also recognised by a distinct clade in the molecular phylogeny (Fig.
Shell large (height 69.1–82.9 mm, width 38.3–42.0 mm), chirally dimorphic, solid, and ovate conical shape. Spire elongate conical with pale colour; apex acute without black spot on tip. Whorls 5–7 convex; suture wide and depressed; last whorl ovate. Periostracum brownish to thin corneous. Shell surface generally with irregular and coarse growth lines; very weak to nearly absent of spiral depression area and keel. Shell colour generally rose-pink to stained with dark brown colour below and ~ 1/2 of upper periphery. Parietal callus thickened, white, and dilated at umbilical area. Aperture broadly ovate; inner side of outer wall with yellow or pale brown 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 short-spatulate with truncated cusp. Lateral teeth bicuspid; endocone small, with wide notch and slightly curved and dull cusp; ectocone large with truncated to blunt cusp. Lateral teeth gradually transformed to asymmetric tricuspid marginal teeth. Outermost teeth with small and curved cusp on endocone and ectocone; mesocone large, with curved cusps (Fig.
Genital organs. Atrium very short. Penis slender, conical, and short ~ 1/2 of vaginal length. Penial retractor muscle thickened and inserting on epiphallus close to penis. Epiphallus long and slender tube. Flagellum short, extending from epiphallus and terminating in slightly enlarged tube. Appendix short, slender tube, approximately as long as flagellum, and ~ 1/3 of epiphallus length. Vas deferens slender tube passing from free oviduct and terminating at epiphallus-flagellum junction (Fig.
Genitalia of Amphidromus spp A–C Amphidromus bozhii Wang, 2019 from Tuy Hoa, Phu Yen, Vietnam (
Vagina slender, long cylindrical, ~ 2× longer than penis. Gametolytic duct enlarged cylindrical tube then abruptly tapering to slender tube terminally and connected to gametolytic sac (missing during dissection). Free oviduct short; oviduct compact, enlarged to form lobule alveoli (Fig.
There were seven COI haplotypes of A. bozhii in this study, and the highest number of mutational steps in the COI minimum spanning network is ten (Fig.
Mitochondrial COI haplotype minimum spanning networks of Amphidromus bozhii Wang, 2019. 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
This species is found in Phu Yen Province, Vietnam.
Amphidromus placostylus
Möllendorff, 1900a: 132. Type locality: Phuc-son [Phuc Son Commune, Tan Yen District, Bac Giang Province, Vietnam].
Amphidromus (Amphidromus) placostylus.
Amphidromus johnstanisici
Thach & Huber in Thach, 2017: 41, pl. 53, figs 657–663. Type locality: Kbang District, Gia Lai Province, Central Vietnam.
Vietnam: Dextral, lectotype of “Amphidromus placostylus”,
Vietnam: 4D + 1S specimens, Dak Po District, Gia Lai Province,
Shells of Amphidromus placostylus Möllendorff, 1900 A lectotype of “Amphidromus placostylus” (
Shell large and chirally dimorphic. Periostracum thick corneous with greenish brown radial streaks. Shell surface generally smooth. Genitalia with appendix.
Amphidromus placostylus is similar to A. schomburgki (Pfeiffer, 1860) in having greenish to greenish brown radial streaks on periostracum, but A. placostylus has a larger shell (height up to nearly 80 mm) with a whitish apertural lip, and A. schomburgki exhibits a relatively smaller shell (height up to 58 mm) with a purplish apertural lip. Amphidromus placostylus is also similar to A. cambojiensis (Reeve, 1860) in having a relatively large shell and ovate to elongate conical shape, but A. placostylus possesses a thick greenish periostracum, uniform whitish shell ground colour, and whitish to dark brown inner side of outer wall. In comparison, A. cambojiensis possesses a thin corneous periostracum, with irregular brown to dark brown radial streaks on the shell ground colour, and a bright purplish pink or violet colour on the inner side of outer wall. Amphidromus placostylus is also recognised by a distinct clade in the molecular phylogeny (Fig.
Shell large (height 64.6–79.5 mm, width 37.4–42.4 mm), chirally dimorphic, solid, and ovate to elongate conical shape. Spire long conical with white colour; apex acute without black spot on tip. Whorls 6–7 convex; suture wide and depressed; last whorl ovate. Periostracum thick corneous or with oblique greenish to greenish brown radial streaks; varix usually absent. Shell surface generally smooth. Shell ground colour monochrome whitish or with dark brownish streaks (without periostracum). Parietal callus thickened and white. Aperture broadly ovate and inner side of outer wall with whitish to dark brown 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 trapezoid-spatulate with truncated cusp. Lateral teeth bicuspid; endocone small, with wide notch and truncated to slightly curved cusp; ectocone large with curved to dull cusp. Lateral teeth gradually transformed to asymmetric tricuspid marginal teeth (Fig.
SEM images of the radula A Amphidromus placostylus Möllendorff, 1900 from Dak Po, Gia Lai, Vietnam (
Genital organs. Atrium relatively short. Penis slender, conical, and short ~ 1/2 of vaginal length. Penial retractor muscle thin, long, inserting on epiphallus close to penis. Epiphallus long, slender tube. Flagellum long, extending from epiphallus and weakly coiled at its end. Appendix short, slender tube, 2× longer than flagellum, and approximately as long as epiphallus. Vas deferens slender tube passing from free oviduct and terminating at epiphallus-flagellum junction (Fig.
Vagina slender, long cylindrical, and ~ 2× longer than penis. Gametolytic duct enlarged cylindrical tube then abruptly tapering to slender tube terminally and connected to gametolytic sac (missing during dissection). Free oviduct short; oviduct compact, enlarged to form lobule alveoli (Fig.
Living specimens
with soft body morphology generally similar to A. ingens. Animals with dark reddish body covered with reticulated skin. Foot broad and long with uniform pale brown colour at foot margin. Head with reddish colour same as body. Upper and lower tentacles with reddish to orange in colour (Fig.
The distribution range of the species covers Bac Giang, Binh Dinh and Gia Lai provinces, Vietnam.
As the original description did not explicitly designate a type or state that the description of this species was based on a single specimen (nor could this be inferred), the designation of a holotype by
This species is known only from a single worn-out lectotype, and the remaining periostracum is only traceable behind the apertural lip. Later, Thach and Huber in
This species also exhibits a prominent population genetic structure, where specimens from the same collecting locality form its own clade (Fig.
Bayesian phylogeny of Amphidromus placostylus Möllendorff, 1900 based on mitochondrial COI and 16S 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).
Shell large and chirally dimorphic. Shell surface with coarse growth lines crossed by weak spiral ridges. Genitalia with appendix.
The new species differs from the closely related A. ingens and A. bozhii in having a generally rounded last whorl, and coarse growth lines crossed with weak spiral ridges. In comparison, the two latter species having a depression area below suture and prominent blunt or keeled on periphery of the last whorl, and having only irregular growth lines on the shell surface. In addition, this new species is recognised by a distinct clade in the molecular phylogeny (Fig.
The specific epithet ingensoides is from ingens, and the suffix –oideus, meaning ‘like or resembling’. This name refers to the resemblance in shell morphology of the new species to the nominal species A. ingens.
Holotype. Vietnam: dextral, shell height 62.1 mm, shell width 36.9 mm, with 6½ whorls, 13 Dec. 2016, coll. A. N. Pham (
Vietnam: Cu’Mta ward, Mdrak District, Dak Lak Province, 12°42'22.9"N, 108°45'13.9"E.
Shell large (height 54.3–67.0 mm, width 32.8–36.8 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 well rounded to slightly angulated. Periostracum brownish to thin corneous; varix usually absent. Shell surface generally with coarse and irregular growth lines crossed by weak spiral ridges. Shell colour 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 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.
Genital organs. Atrium relatively short. Penis slender, conical, and short ~ 1/3 of vaginal length. Penial retractor muscle thickened, short and inserting on epiphallus close to penis. Epiphallus long, slender tube, coiled and twisted upon itself. Flagellum long, extending from epiphallus and terminating in slightly enlarged folded coil. Appendix short, slender tube, ~ 2× longer than flagellum, and approximately as long as epiphallus. Vas deferens slender tube passing from free oviduct and terminating at epiphallus-flagellum junction (Fig.
Genitalia of Amphidromus spp A–C Amphidromus ingensoides sp. nov. from Hon Ba, Khanh Son, Khanh Hoa, Vietnam (
Vagina slender, long cylindrical, and ~ 3× longer than penis. Gametolytic duct enlarged cylindrical tube then abruptly tapering to slender tube terminally and connected to gametolytic sac (missing during dissection). Free oviduct short; oviduct compact and enlarged to form lobule alveoli (Fig.
Living specimens
with soft body morphology generally similar to A. ingens. Animals with pale yellowish body covered with reticulated skin, anterior body usually with dark reticulated strip dorsally. Foot broad and long, and with narrow and orange colour stripe above foot margin. Head with orange patch covering tentacles. Upper and lower tentacles orange to paler in colour (Fig.
This species is found in Dak Lak and Khanh Hoa provinces, Vietnam.
As a small number of specimens were dissected, this new species seems to have a vagina shorter than penis + epiphallus length, while A. ingens and A. bozhii have a vagina almost as long as penis + epiphallus. In addition, A. ingensoides sp. nov. possesses a longer appendix than the geographically closer species A. ingens from M’drak District, Dak Lak Province.
Amphidromus
(Goniodromus) bülowi Fruhstorfer, 1905: 83–84, pl. 1, fig. 2. Type locality: West-Sumatra.
Amphidromus bülowi.
Amphidromus (Goniodromus) asper
Haas, 1934: 96, figs 11, 12. Type locality: Süd-Annam, 120 km von der Küste, auf dem Wege zum Plateau von Lang-Bian, zw. 600–1000 m [South Annam, 120 km from the coast, on the way to the plateau of Lang-Bian, between 600–1000 m].
Amphidromus asper.
Amphidromus bulowi
[sic].
Amphidromus (Goniodromus) bulowi bulowi
[sic].
Amphidromus franzhuberi
Thach, 2016: 64–65, fig. 42; pl. 23, figs 315–319. Type locality: along the border of Nha Trang outskirts and Khanh Vinh District, Khanh Hoa Province (Central Vietnam).
Amphidromus buelowi.
Indonesia: Sinistral, lectotype of “Amphidromus buelowi”,
Indonesia: 2D specimens, Padang Sökeli, Singalang,
Shells of Amphidromus buelowi Fruhstorfer, 1905 A lectotype of “Amphidromus buelowi” (
Vietnam: 2D specimens, Lang-Biang, Annam,
Shell large and chirally dimorphic. Shell colour with irregularly zigzag of dark radial streaks, and dark triangular blotches. Aperture elliptical ovate with more or less prominent anterior notch and umbilical hump; twisted columella plait. Genitalia with appendix.
Amphidromus buelowi differs from the similar species A. asperoides sp. nov. in having a distinct twisted columella plait, a prominent umbilical hump encircling columellar area, and an apertural notch projecting anteriorly. In contrast, A. asperoides sp. nov. possesses a straight columella, and without apertural notch and umbilical hump. In addition, on the soft body of living snail, the entire body of A. buelowi is reddish orange, while A. asperoides sp. nov. exhibits a uniform brownish yellow to pale brown body. Amphidromus buelowi is also recognised by a distinct clade in the molecular phylogeny (Fig.
Shell large (height 45.3–51.1 mm, width 26.2–26.6 mm), chirally dimorphic, solid, and ovate conical. Spire conical with white or pale colour; apex acute without black spot on tip. Whorls 6–7 little convex to smooth; suture wide and shallow; last whorl well rounded to slightly elongated and with more or less prominent umbilical hump. Periostracum thin corneous; varices generally present. Shell ground colour pale yellowish, decorated with irregular zigzag of dark radial streaks, and dark triangular blotches connected with dark streaks. Parietal callus thickened, white and much thinner in central area. Aperture elliptical ovate; with more or less anterior notch; inner side of outer wall whitish colour; peristome thickened, expanded, and reflexed but not attached to last whorl; lip whitish. Columella white, straight and with distinct twisted plait. Umbilicus imperforate.
Radula. Teeth arranged in anteriorly pointed V-shaped rows. Central tooth monocuspid and slightly elongate-spatulate teeth with truncated cusp. Lateral teeth bicuspid; endocone curved with wide notch and blunt cusp; ectocone large with truncated cusp. Lateral teeth gradually transformed to asymmetric tricuspid marginal teeth. Outermost teeth with small and curved cusp on ectocone, and endocone and mesocone with curved cusps (Fig.
Genital organs. Atrium relatively short. Penis slender, conical, and nearly as long as vagina. Penial retractor muscle inserting on epiphallus close to penis. Epiphallus long, slender tube, and almost same diameter as penis. Flagellum short, extending from epiphallus and terminating in slightly enlarged folded coil. Appendix short, thin tube, 3× longer than flagellum, and approximately as long as epiphallus. Vas deferens slender tube passing from free oviduct and terminating at epiphallus-flagellum junction (Fig.
Vagina slender, long cylindrical, and ~ 2× longer than penis. Gametolytic duct enlarged cylindrical tube then abruptly tapering to long, slender tube terminally, connected to elongate gametolytic sac. Free oviduct short; oviduct compact, enlarged to form lobule alveoli (Fig.
Living specimens
with soft body morphology generally similar to A. ingens. Animals with reddish orange body covered with reticulated skin. Lateral of body vary from yellowish (in younger specimen) to dark reddish orange colour (older specimens). Foot broad and long with reddish orange colour near foot sole margin. Head and dorsal of anterior body with reddish orange to dark colour. Upper tentacles pale reddish orange to brownish; lower tentacles short and paler in colour (Fig.
There was a total of four COI haplotypes (Fig.
Mitochondrial haplotype minimum spanning networks of Amphidromus buelowi Fruhstorfer, 1905 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
The species has a widely disjunct distribution: one in Mount Singgalang, West Sumatra, Indonesia, and some localities in Khanh Hoa and Lam Dong provinces, South Vietnam.
This species was originally described by
Shells of Amphidromus thachi Huber, 2015 A holotype of “Amphidromus thachi” (
Amphidromus thachi
Huber, 2015: 29–30, figs 1–8. Type locality: outskirts of Nha Trang area, about 30 km southeast of Nha Trang city (Cam Lam District, Khanh Hoa Province, central Vietnam), at some distance from the village and the National Road No 1A.
Amphidromus thachi krisi
Thach, 2018: 63–64, pl. 70, figs 833–837. Type locality: Lac Duong District, Lam Dong Province, South Vietnam.
Vietnam: Dextral, holotype of “Amphidromus thachi”,
Vietnam: 1D + 1S specimens, fin de la route de Hon Ba (chalets de Yersin), Commune de Suoi Cat, Province de Khanh Hoa, Vietnam,
Shell medium and chirally dimorphic. Aperture obliquely elliptical with prominent anterior notch; columella bending anteriorly. Parietal callus, lip and columella whitish or with dark brown. Genitalia with appendix.
Amphidromus thachi is unique compared to all Vietnamese species reported by
Shell medium (height 25.0–30.0 mm, width 17.0–18.5 mm), chirally dimorphic, thin to slightly thickened, and conical. Spire short conical with white or pale colouration; apex acute without black spot on tip. Whorls 6–7 little convex to smooth; suture wide and shallow; last whorl well rounded to slightly elongated and with less prominent umbilical hump. Periostracum thin corneous; varices absent. Shell colour uniform whitish to pale cream; subsutural band opaque white. Parietal callus thickened, whitish and translucent or dark to dark brown. Aperture elliptical to obliquely elliptical with prominent anterior notch; inner side of outer wall whitish; peristome thickened, slightly expanded not reflected; lip whitish or with dark to dark brown. Columella whitish or dark, shortly straight then bending anteriorly. Umbilicus imperforate.
Radula. Teeth arranged in anteriorly pointed V-shaped rows. Central tooth monocuspid and spatulate with truncated cusp. Lateral teeth bicuspid; endocone slightly smaller than ectocone, curved, with wide notch and dull cusp; ectocone large with curved to dull cusp. Lateral teeth gradually transformed to asymmetric tricuspid marginal teeth. Outermost teeth with small and curved cusp on ectocone; endocone and mesocone with curved cusps (Fig.
Genital organs. Atrium relatively short. Penis slender, conical, and short, ~ 1/2 of vaginal length. Penial retractor muscle thickened and inserting on epiphallus close to penis. Epiphallus long, slender tube, almost same diameter as penis. Flagellum short, extending from epiphallus and terminating in weakly coiled. Appendix short, slender tube, similar length with flagellum, and ~ 1/2 of epiphallus length. Vas deferens slender tube passing from free oviduct and terminating at epiphallus-flagellum junction (Fig.
Genitalia of Amphidromus spp A–D Amphidromus thachi Huber, 2015 A general view of genitalia of specimen from Krong Bong, Dak Lak, Vietnam (
Vagina slender, cylindrical, and ~ 2× longer than penis. Gametolytic organ relatively short than other congeners: gametolytic duct shorter to slightly longer than vagina, cylindrical tube, then tapering to short, slender tube terminally; gametolytic sac globular shape. Free oviduct short; oviduct compact, enlarged to form lobule alveoli (Fig.
Living specimens
with soft body morphology generally similar to A. ingens. Animals with whitish to creamy body covered with reticulated skin. Foot broad and long with uniform whitish to creamy colouration to posterior tail. Head with whitish or sometimes with yellowish colour. Upper tentacles drumstick-shaped, greyish to brownish, with dark eyespots on tentacular tips; lower tentacles short and greyish in colour (Fig.
There was a total of six COI haplotypes (Fig.
Mitochondrial haplotype minimum spanning networks of Amphidromus thachi Huber, 2015 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
The distribution range of this species covers Binh Dinh, Dak Lak, Khanh Hoa, and Lam Dong provinces, Vietnam.
This species was originally described by
Two dissected specimens were found to have different lengths of the gametolytic duct. The specimen XM2 from Krong Bong, Dak Lak, Vietnam has a shorter gametolytic duct (Fig.
Amphidromus metabletus
Möllendorff, 1900b: 22–23. Type locality: Berg “Mutter und Kind”, Annam [Vietnam].
Amphidromus metabletus pachychilus
Möllendorff, 1901: 49. Type locality: Nha-trang, Süd-Annam [Nha Trang, Khanh Hoa Province, Vietnam].
Amphidromus metabletus insularis
Möllendorff, 1901: 49–50. Type locality: Insel Bai-min bei Nha-trang.
Amphidromus metableta
[sic].
Amphidromus metableta pachychilus
[sic].
Amphidromus metableta insularis
[sic].
Amphidromus (Amphidromus) metabletus metabletus.
Amphidromus
(Amphidromus) metabletusinsularis.
Amphidromus
(Amphidromus) metabletus pachychilus.
Vietnam: Dextral, lectotype of “Amphidromus metabletus”,
Shells of Amphidromus metabletus Möllendorff, 1900 A lectotype of “Amphidromus metabletus” (
Shells of Amphidromus metabletus Möllendorff, 1900 A paralectotype of “Amphidromus metabletus pachychilus ” forma confluens (
Vietnam: 4D + 4S specimens, Nha Trang city, Khanh Hoa Province,
Shell medium to large, elongate conical, and chirally dimorphic. Spire elongate conical; aperture ovate. Genitalia with appendix.
The monochromic form of the chirally dimorphic A. metabletus is similar to A. cochinchinensis (Pfeiffer, 1857) in having a monochrome whitish yellow shell, but A. cochinchinensis is distinct in having a very little expanded lip, elongate last whorl, and elliptical aperture (
Shell medium to large (height 36.5–46.5 mm, width 20.9–27.2 mm), chirally dimorphic, elongate conical, rather thick and glossy. Spire elongate conical to ovate conical; apex acute, without black spot on tip, and earlier whorls whitish to tinted pink. Whorls 6–7 convex to smooth; suture wide and shallow; last whorl well rounded. Periostracum thin corneous; varix usually absent. Shell ground colour varying from whitish, yellowish to reddish brown; banding pattern variable from non-banded (monochrome colour) to narrow to wide multiple reddish brown spiral bands on whitish or yellowish ground colour. Parietal callus slightly thickened, whitish or transparent. Aperture ovate; peristome expanded and not reflected; lip whitish. Columella straight, thick or thin. Umbilicus imperforate.
Radula. Teeth arranged in anteriorly pointed V-shaped rows. Central tooth monocuspid and short spatulate with truncated cusp. Lateral teeth bicuspid; endocone small, with wide notch and blunt cusp; ectocone large with blunt cusp. Lateral teeth gradually transformed to asymmetric tricuspid marginal teeth (Fig.
SEM images of the radula A Amphidromus metabletus Möllendorff, 1900 from Nha Trang, Khanh Hoa, Vietnam (
Genital organs. Atrium relatively short. Penis slender, and short ~ ¼ of vaginal length. Penial retractor muscle thin, long and inserting on epiphallus close to penis. Epiphallus long, slender tube, and almost same diameter as penis. Flagellum short, extending from epiphallus and terminating in slightly enlarged folded coil. Appendix long, slender tube, ~ 3× longer than flagellum, and approximately as long as epiphallus. Vas deferens slender tube passing from free oviduct and terminating at epiphallus-flagellum junction (Fig.
Vagina slender, long cylindrical, and ~ 4× longer than penis. Gametolytic duct very long cylindrical tube then abruptly tapering to slender tube terminally and connected to globular gametolytic sac. Free oviduct short; oviduct compact, forming lobule alveoli (Fig.
There were 12 COI haplotypes (Fig.
Mitochondrial haplotype minimum spanning networks of Amphidromus metabletus Möllendorff, 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
This species is found in Khanh Hoa Province, Vietnam.
One species that was described earlier, A. cochinchinensis was originally described from “Cochin China”, the old geographic usage which is now interpreted as southern Vietnam, and this species was known only from the type materials (
Amphidromus haematostoma
Möllendorff, 1898: 74–75. Type locality: Boloven [Boloven Plateau, Champasak, Laos].
Amphidromus haematostoma var. viridis
Möllendorff, 1898: 75. Type locality: Boloven.
Amphidromus haematostoma var. varians
Möllendorff, 1898: 75. Type locality: Boloven.
Amphidromus (Syndromus) haematostoma.
Amphidromus haematostomus
[sic].
Amphidromus haematostomus
[sic] varians.
Amphidromus haematostomus
[sic] viridis.
Amphidromus haematostoma varians.
Amphidromus haematostoma viridis.
Amphidromus (Syndromus) haematostomus
[sic].
Amphidromus attapeuensis
Thach & Huber in Thach, 2017: 37–38, figs 573–578. Type locality: Attapeu Province, southeast of Laos, close to Vietnam border.
Laos: Sinistral, lectotype of “Amphidromus haematostoma var. viridis”,
Shells of Amphidromus spp A–G Amphidromus haematostoma Möllendorff, 1898 A Lectotype of “Amphidromus haematostoma var. viridis” (
Laos: 5S specimens, Xe Pian village, Paksong District, Champasak Province,
Vietnam: 5S specimens, Kbang District, Gia Lai Province,
Shell medium and sinistral. Parietal callus, lip and columella with bright to dark rose-pink. Varix sometimes present. Genitalia without appendix.
Amphidromus haematostoma differs from the similar sinistral species A. madelineae in having a whitish apex, slightly thickened parietal callus with pale to dark rose-pink colouration, while A. madelineae has tinted pink ~ 1–2 whorls from apex, and thin transparent parietal callus. This species also differs from the similar A. roseolabiatus in that the latter has a chirally dimorphic shell, a whitish apex and the genitalia with a very long appendix. The molecular phylogeny in this study reveals that A. haematostoma is a distinct clade from its sister A. madelineae (Fig.
Shell medium (height 23.8–35.4 mm, width 13.3–21.0 mm), sinistral, ovate conical, rather thin and glossy. Spire elongate conical; apex acute, without black spot on tip, and earlier whorls whitish. Whorls 6–7 convex to smooth; suture wide and depressed; last whorl well rounded. Periostracum thick corneous or with green to greenish yellow colour; varix occasionally present. Shell ground colour white or yellowish colour (without periostracum); dark yellow subsutural band and a band at around umbilicus usually present (rarely indistinguishable). Parietal callus thickened with bright to dark rose-pink colour. Aperture broadly ovate and inner side of outer wall whitish; peristome little thickened, expanded, and weakly reflexed but not attached to last whorl; lip bright to dark rose-pink colour and with little darker colour at the edge. Columella bright to dark rose-pink colour, straight, or little twisted. Umbilicus imperforate.
Genital organs. Atrium relatively short. Penis slender, conical, and short ~ 1/3 of vaginal length. Penial retractor muscle thickened, long and inserting on epiphallus close to penis. Epiphallus stout tube and approximately as long as vagina. Flagellum short, extending from epiphallus and terminating in curved tip; appendix absent. Vas deferens slender tube passing from free oviduct and terminating at epiphallus-flagellum junction (Fig.
Genitalia of Amphidromus spp A, B Amphidromus haematostoma Möllendorff, 1898 from Ba Chien, Pakse, Champasak, Laos (
Vagina slender, long cylindrical, and ~ 2× longer than penis. Gametolytic duct cylindrical tube then gradually tapering to slender tube terminally and connected to gametolytic sac (missing during dissection). Free oviduct short; oviduct compact, forming lobule alveoli (Fig.
This species has a wide distribution range covering Attapeu, Champasak, and Phongsali provinces, Laos, and Gia Lai Province, Vietnam.
A degree of shell colour variation occurs in the specimens from Pakse, Champasak, Laos (Fig.
This species also exhibits a prominent population genetic structure, where some clades constitute only the specimens from the same collecting locality (Fig.
Bayesian phylogeny of Amphidromus haematostoma Möllendorff, 1898 and Amphidromus madelineae Thach, 2020 based on mitochondrial COI and 16S 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).
Amphidromus madelineae
Thach, 2020a: 68–69, pl. 48, figs 592, 593; pl. 49 figs 594–596. Type locality: Quang Nam Province, Central Vietnam.
Vietnam: Sinistral, holotype of “Amphidromus madelineae”,
Vietnam: 5S specimens, Duy Xuyen District, Quang Nam Province,
Shell small to medium, sinistral; apex tinted pink to purplish pink. Parietal callus transparent; lip whitish to purplish pink; columella and inner side of outer wall around columella purplish pink. Genitalia without appendix.
Amphidromus madelineae differs from the similar sinistral species A. haematostoma in having tinted-pink colour ~ 1–2 whorls from apex, and thin and transparent parietal callus, while A. haematostoma has a whitish apex, slightly thickened parietal callus with pale to dark rose-pink colour. This species also differs from the similar A. roseolabiatus in that the latter has a chirally dimorphic shell, a whitish apex and the genitalia with a very long appendix. The molecular phylogeny in this study reveals that A. madelineae is a distinct clade from its sister A. haematostoma (Figs
Shell small to medium (height 27.7–38.0 mm, width 16.2–20.2 mm), sinistral, elongate to ovate conical, rather thin and glossy. Spire conical; apex acute, tinted pink to purplish pink and without black spot on tip. Whorls 5–6 nearly smooth; suture wide and shallow; last whorl rounded to nearly globose. Periostracum usually deciduous to yellowish green radial streaks, more conspicuous on last whorl and faded in earlier whorls. Last whorl with thin, dark green subsutural band, sometimes with irregular greenish spiral blotched bands below periphery; varix sometimes present. Parietal callus thin and transparent. Aperture ovate to elongate; peristome little thickened and expanded; lip generally whitish to purplish pink; inner side of outer wall whitish around columella with purplish pink colour. Columella straight, thickened and pale to dark purplish pink. 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 elongate, with wide and deep notch, and dull cusp; ectocone large with slightly blunt to dull cusp. Lateral teeth gradually transformed to asymmetric tricuspid marginal teeth. Outermost teeth with small and multicuspid (Fig.
Genital organs. Atrium relatively short. Penis stout, cylindrical, and short, ~ 1/2 as long as vagina. Penial retractor muscle thickened, short and inserting on epiphallus close to penis. Epiphallus stout tube and approximately as long as vagina. Flagellum short, extending from epiphallus and terminating in slightly curved tip; appendix absent. Vas deferens slender tube passing from free oviduct and terminating at epiphallus-flagellum junction (Fig.
Vagina long cylindrical, and ~ 2× longer than penis. Gametolytic duct long cylindrical tube then gradually tapering to slender tube terminally and connected to bulbus gametolytic sac. Free oviduct short; oviduct compact, forming lobule alveoli (Fig.
This species is found in Quang Nam Province, Vietnam.
Specimens from Za Hung, Dong Giang, Quang Nam, Vietnam (Fig.
Amphidromus costifer
Smith, 1893: 12, text fig. Type locality: dans les Montagnes boitées du Huyen de Tri-phuoc, Province Binh-dinh, An-nam [in the Huyen Mountains of Tri-phuoc, Binh-dinh Province, An-nam].
Amphidromus costifer gemmalimae
Thach, 2020a: 55, pl. 45, figs 551–557. Type locality: Krong Nang, Dak Lak Province, Central Vietnam.
Amphidromus nguyenkhoai
Thach, 2020a: 71, pl. 64, figs 776–784. Type locality: Krong Pa District, Gia Lai, Central Vietnam.
Vietnam: Dextral, lectotype of “Amphidromus costifer”,
Vietnam: 10D specimens, Tay Son District, Binh Dinh Province,
Shells of Amphidromus costifer Smith, 1893 A lectotype of “Amphidromus costifer” (
Shell large, dextral, and spire ovate conical. Shell surface with prominent irregular growth lines or prominent crests of expanded lip. Aperture broadly ovate or truncate. Genitalia with appendix.
Amphidromus costifer is unique among all reported Vietnamese species (
Shell large (height 48.9–59.7 mm, width 27.3–34.8 mm), dextral, solid, and ovate conical shape. Spire ovate conical; apex acute without black spot on tip. Whorls 5–7 little convex; suture wide and shallow; last whorl large, rounded to slightly ovate. Periostracum brownish to thin corneous; strong varix usually absent. Shell surface: spire generally with prominent irregular growth lines or with weak radial streak; last whorl with strong irregular growth lines, coarse or with prominent radial ridges, and usually prominent crest of expanded lip present. Shell colour highly variable: spire generally uniform whitish to yellowish (pale yellowish subsutural band detectable); last whorl has no pattern but usually stained with dark to dark brown blotches, smear or radial streaks. Parietal callus thickened and white, and broadly dilated at umbilical area. Aperture broadly ovate or truncate (sometimes irregular); inner side of outer wall generally whitish to yellowish. Peristome thickened, expanded, and slightly reflexed; lip whitish. Columella white and straight. Umbilicus imperforate.
Radula. Teeth arranged in anteriorly pointed V-shaped rows. Central tooth monocuspid and spatulate with truncated cusp. Lateral teeth bicuspid; endocone slightly curved with wide notch and curved cusp; ectocone large with truncated to blunt cusp. Lateral teeth gradually transformed to asymmetric tricuspid marginal teeth. Outermost teeth with tiny ectocone; endocone and mesocone large with curved cusps (Fig.
Genital organs. Atrium relatively short. Penis enlarged, conical, and nearly 1/2 as long as vagina. Penial retractor muscle thickened and inserting on epiphallus close to penis. Epiphallus long and slender tube. Flagellum short, extending from epiphallus, approximately as long as penis, and terminating in slightly enlarged coil. Appendix short, slender tube, 3×longer than flagellum and approximately as long as epiphallus. Vas deferens slender tube passing from free oviduct and terminating at epiphallus-flagellum junction (Fig.
Genitalia of Amphidromus spp A–C Amphidromus costifer Smith, 1893 from Ea Sup, Dak Lak, Vietnam (
Vagina slender, long cylindrical, and ~ 2× longer than penis. Gametolytic duct cylindrical tube, extremely enlarged then abruptly tapering to slender tube terminally and connected to enlarged elliptical gametolytic sac. Free oviduct short; oviduct compact, enlarged to form lobule alveoli (Fig.
There was a total of seven 16S haplotypes (Fig.
Mitochondrial 16S haplotype minimum spanning networks of Amphidromus costifer Smith, 1893. 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
The distribution range of the species covers Binh Dinh, Dak Lak, and Gia Lai provinces, Vietnam.
As
Our recent specimens with a monochrome whitish shell identical to the holotype of A. nguyenkhoai were found to belong to the same clade as the typical A. costifer, with 14–18 mutational steps to the other specimens in the 16S haplotype network (Fig.
The subspecies A. costifer gemmalimae was described as distinct from the nominotypical subspecies in having a stouter shell shape, smoother, not well-defined and not strongly calloused parietal wall, axial ribs with regular strength, a regularly convex outer rib, a completely closed umbilicus, and a columella not widening laterally (
Additional shell variations, which occur in the monochrome whitish specimens from An Lao, Binh Dinh, Vietnam (Fig.
The COI intraspecific distance among all A. costifer specimens is 7.84%, which is the second highest distance of all Amphidromus species in this study. This value is higher than the optimum intra/interspecific threshold value of 4% for stylommatophoran land snails (
Amphidromus roseolabiatus
Fulton, 1896: 89, pl. 6, fig. 8. Type locality: Siam [Thailand].
Amphidromus (Amphidromus) roseolabiatus.
Amphidromus phuonglinhae
Thach, 2017: 45, pl. 46, figs 581–584. Type locality: Bo Trach District, Quang Binh Province, Central Vietnam.
Thailand: Sinistral, lectotype of “Amphidromus roseolabiatus”,
Vietnam: Sinistral, holotype of “Amphidromus phuonglinhae”,
Cambodia: 4D + 6S specimens, Kampong Siem District, Kampong Cham Province,
Shells of Amphidromus spp A–F Amphidromus roseolabiatus Fulton, 1896 A lectotype of “Amphidromus roseolabiatus” (
Shell medium and chirally dimorphic. Parietal callus transparent; lip and columella purplish pink. Genitalia with appendix.
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 (
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.
There was one COI haplotype of A. roseolabiatus in this study (Fig.
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
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
Amphidromus pankowskiana [sic] Thach, 2020a: 72–73, pl. 48, figs 582–586. Type locality: Northwestern District of Khanh Hoa Province, Central Vietnam.
Amphidromus pankowskianus.
Vietnam: Holotype,
Laos: 2D + 1S specimens, Khammouan Province, near Minh Hoa District, Quang Binh Province, Vietnam,
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.
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.
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.
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.
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.
This species is found in Bolikhamsai and Khammouan provinces, Laos, and Khanh Hoa Province, Vietnam.
Empty shells from Phong Nha National Park, Quang Binh Province, Vietnam, identified as ‘A. roseolabiatus’ in
Arboreal snails in the genus Amphidromus exhibit high levels of variation in intraspecific shell colour and pattern (
Apart from examining the reciprocal monophyly of each species, the use of interspecific genetic distances is another means to set the preliminary cut-off for each clade to become putative species, although the use of interspecific genetic distances has been discussed as an unfavourable way to delimit species (
Although there is still no general 16S intra/interspecific threshold value for stylommatophoran land snails, we could estimate the threshold for the Camaenidae to some extent. In this study, we identify a range of 3–5% as the 16S interspecific threshold value for Amphidromus. This range is comparable to the lower boundary of 16S interspecific distances reported in other genera in the Camaenidae, e.g., Aegistohadra from China and Vietnam (5.97–11.86%;
Internal morphological characters, especially those of reproductive system such as penis and vagina, are often species-specific and therefore are interpreted as the prime species recognition characters (
The non-monophyly of Amphidromus species exhibiting the same chirality state (exclusively sinistral or dextral, or chirally dimorphic) illustrates that the multiple origins of left–right coiling reversal are common in terrestrial snails (
Special thanks go to Philippe Bouchet, Virginie Héros, Manuel Caballer, Philippe Maestrati, Alexandre Lardeur, and Priscillia Bourguignon (
The authors have declared that no competing interests exist.
No ethical statement was reported.
This project is partially funded by the National Research Council of Thailand (NRCT-N35E660138) and Thailand Research Fund (grant no. DBG 6080011) to CS.
Conceptualization: CS, PJ, CTL. Data curation: PJ, CS, CTL. Formal analysis: PJ. Funding acquisition: CS. Investigation: CWH, CTL, PJ, CS. Methodology: CS, CWH, PJ, CTL. Project administration: PJ. Resources: CS, CTL. Validation: CWH, CTL. Visualization: PJ. Writing - original draft: CS, PJ. Writing - review and editing: CWH, CTL.
Parin Jirapatrasilp https://orcid.org/0000-0002-5591-6724
Chih-Wei Huang https://orcid.org/0000-0002-2921-4294
Chirasak Sutcharit https://orcid.org/0000-0001-7670-9540
Chi-Tse Lee https://orcid.org/0000-0003-2695-0680
All of the data that support the findings of this study are available in the main text or Supplementary Information.
Bayesian phylogenetic tree of Amphidromus spp.
Data type: jpg