Five times over: 42 new Angustopila species highlight Southeast Asia's rich biodiversity (Gastropoda, Stylommatophora, Hypselostomatidae).

The Southeast Asian genus Angustopila, currently comprising 13 nominal species, encompasses the world's tiniest land snails. This work shows that there are far more species than previously suspected, and that this genus is in fact, a very speciose group of tiny snails widely distributed in Southeast Asia. Angustopila is revised based on type material of known species as well as 211 samples newly collected in China, Laos, Myanmar, Thailand and Vietnam. Altogether, 53 species and one subspecies are recognised, of which 42 species and subspecies are new to science: A.akrodon Páll-Gergely & Hunyadi, sp. nov., A.apiaria Páll-Gergely & Hunyadi, sp. nov., A.apiostoma Páll-Gergely & Vermeulen, sp. nov., A.apokritodon Páll-Gergely & Hunyadi, sp. nov., A.antidomedon Páll-Gergely & Hunyadi, sp. nov., A.babel Páll-Gergely & Vermeulen, sp. nov., A.bathyodon Páll-Gergely & Hunyadi, sp. nov., A.bidentata Páll-Gergely & Jochum, sp. nov., A.cavicola Páll-Gergely & Dumrongrojwattana, sp. nov., A.cicatricosa Páll-Gergely & Vermeulen, sp. nov., A.coprologosuninodus Páll-Gergely & Grego, ssp. nov., A.erawanica Páll-Gergely & Dumrongrojwattana, sp. nov., A.fratermajor Páll-Gergely & Vermeulen, sp. nov., A.fraterminor Páll-Gergely & Vermeulen, sp. nov., A.gracilis Páll-Gergely & Hunyadi, sp. nov., A.halongensis Páll-Gergely & Vermeulen, sp. nov., A.hyron Páll-Gergely & Vermeulen, sp. nov., A.maasseni Páll-Gergely & Vermeulen, sp. nov., A.majuscula Páll-Gergely & Hunyadi, sp. nov., A.margaritarion Páll-Gergely & Hunyadi, sp. nov., A.megastoma Páll-Gergely & Vermeulen, sp. nov., A.occidentalis Páll-Gergely & Hunyadi, sp. nov., A.oostoma Páll-Gergely & Vermeulen, sp. nov., A.papaver Páll-Gergely & Hunyadi, sp. nov., A.parallela Páll-Gergely & Hunyadi, sp. nov., A.prolixa Páll-Gergely & Hunyadi, sp. nov., A.pusilla Páll-Gergely & Hunyadi, sp. nov., A.pustulata Páll-Gergely & Hunyadi, sp. nov., A.quadridens Páll-Gergely & Vermeulen, sp. nov., A.rara Páll-Gergely & Hunyadi, sp. nov., A.reticulata Páll-Gergely & Hunyadi, sp. nov., A.somsaki Páll-Gergely & Hunyadi, sp. nov., A.steffeki Páll-Gergely & Grego, sp. nov., A.tetradon Páll-Gergely & Hunyadi, sp. nov., A.thersites Páll-Gergely & Vermeulen, sp. nov., A.tonkinospiroides Páll-Gergely & Vermeulen, sp. nov., A.tridentata Páll-Gergely & Hunyadi, sp. nov., A.tweediei Páll-Gergely & Hunyadi, sp. nov., A.uvula Páll-Gergely & Hunyadi, sp. nov., A.vandevenderi Páll-Gergely & Jochum, sp. nov., A.vitrina Páll-Gergely & Hunyadi, sp. nov., A.vomer Páll-Gergely & Hunyadi, sp. nov., A.werneri Páll-Gergely & Hunyadi, sp. nov. Angustopilasubelevata Páll-Gergely & Hunyadi, 2015 is moved to the synonymy of Angustopilaelevata (F. G. Thompson & Upatham, 1997), and A.singuladentis Inkhavilay & Panha, 2016 is a junior synonym of A.fabella Páll-Gergely & Hunyadi, 2015. Three species, namely A.elevata, A.fabella and A.szekeresi, are widespread over several hundred kilometres while some other species (A.huoyani, A.parallelasp. nov., A.cavicolasp. nov.) are known from just two sites a few hundred kilometres apart. All others are small range or single-site endemics. The reproductive anatomy of A.erawanicasp. nov. is described.

A review of the genus Laeocathaica Möllendorff, 1899 (Gastropoda, Pulmonata, Camaenidae).

In this paper an overview of the Laeocathaica species is provided, and the intraspecific variability of several Laeocathaica species demonstrated on multiple shells. Laeocathaicahisanoi Páll-Gergely, sp. nov. and L.minwui Páll-Gergely, sp. nov. are described based on specimens found in museum collections. Five new synonyms are recognized: L.prionotropisalbocincta Möllendorff, 1899 is a new synonym of L.prionotropis Möllendorff, 1899, L.stenochone Möllendorff, 1899 is a new synonym of Laeocathaicacarinifera (H. Adams, 1870). Laeocathaicadistinguenda Möllendorff, 1899, L.tropidorhaphe Möllendorff, 1899, and L.dangchangensis Chen & Zhang, 2004 are moved to the synonymy of Laeocathaicaamdoana Möllendorff, 1899. Furthermore, photos of paratypes of Cathaicabizonalis Chen & Zhang, 2004 are published for the first time.

Nineteen new species of Alycaeidae from Myanmar and Thailand (Gastropoda: Caenogastropoda: Cyclophoroidea).

Nineteen new species of the alycaeid genera Chamalycaeus, Dicharax, and Metalycaeus are described from Thailand and Myanmar: Chamalycaeus buaboke Páll-Gergely A. Reischütz, n. sp., C. erawan Páll-Gergely Hunyadi, n. sp., C. hirpex Páll-Gergely A. Reischütz, n. sp., C. irmatallus Páll-Gergely, n. sp., C. krabiensis Páll-Gergely A. Reischütz, n. sp., C. serratus Páll-Gergely Auffenberg, n. sp., C. spiratus Páll-Gergely, n. sp., Dicharax (?) admirandus Páll-Gergely Auffenberg, n. sp., D. cyclostoma Páll-Gergely, n. sp., D. ebrius Páll-Gergely Auffenberg, n. sp., D. (?) gnomus Páll-Gergely, n. sp., D. mirounga Páll-Gergely, n. sp., D. ovatus Páll-Gergely Auffenberg, n. sp., D. subroseus Páll-Gergely, n. sp., D. verrucosus Páll-Gergely Hunyadi, n. sp., Metalycaeus anas Páll-Gergely A. Reischütz, n. sp., M. aries Páll-Gergely Auffenberg, n. sp., M. bicarinatus Páll-Gergely Hunyadi, n. sp., M. pygmachos Páll-Gergely Hunyadi, n. sp. Alycaeus kengtungensis Godwin-Austen, 1914 is moved to the synonymy of Metalycaeus heudei (Bavay Dautzenberg, 1900). We also report exact localities of Dicharax ataranensis (Godwin-Austen, 1914), Dicharax notus (Godwin-Austen, 1914), and Dicharax omissus (Godwin-Austen, 1914). The new records extend the known distribution of Chamalycaeus and Metalycaeus in Thailand.

Revision of the Alycaeidae of China, Laos and Vietnam (Gastropoda: Cyclophoroidea) I: The genera Dicharax and Metalycaeus.

This is the first part of the revision of the Alycaeidae of China, Laos and Vietnam. Here we revise the species hitherto classified in Chamalycaeus Möllendorff, 1897 (genera Dicharax and Metalycaeus in this study). We show that no Chamalycaeus live in the region, and the alycaeid species of the investigated region can be classified into five genera: Alycaeus Baird, 1850, Dicharax Kobelt & Möllendorff, 1900, Dioryx Benson, 1859, Metalycaeus Pilsbry, 1900 and Pincerna Preston, 1907. We propose Dioryx dautzenbergi Páll-Gergely nom. nov. as a replacement name for Alycaeus (Dioryx) major Bavay & Dautzenberg, 1900, non Alycæus (Dioryx) granum var. major Godwin-Austen, 1893. Alycaeus anceyi Mabille, 1887, A. eydouxi Venmans, 1956, A. mouhoti L. Pfeiffer, 1862, A. rolfbrandti Maassen, 2006 and A. vanbuensis Bavay & Dautzenberg, 1900 are retained in Alycaeus. Alycaeus costulosa Bavay & Dautzenberg, 1912 and A. maolanensis Luo, Zhang & Zhuo 2009 were transferred to Pincerna. We examined newly collected specimens and the type specimens of all species with the exception of the following: A. elevatus Heude, 1886, A. expansus Heude, 1890, A. neglectus Heude, 1885, Chamalycaeus libonensis Chen, Li & Luo 2003, C. panshiensis Chen, 1989, C. tangmaiensis Chen & Zhang, 2001, C. zayuensis Zhang, Chen & Zhou, 2008. Fifteen new species are described as follows: Dicharax (?) abdoui Páll-Gergely, n. sp., Dicharax (?) alticola Páll-Gergely & Hunyadi n. sp., Dicharax (?) ellipticus Páll-Gergely n. sp., Dicharax (?) immaculatus Páll-Gergely n. sp., Dicharax bison Páll-Gergely & Hunyadi n. sp., Dicharax draco Páll-Gergely & Hunyadi n. sp., Dicharax imitator Páll-Gergely & Hunyadi n. sp., Dicharax microcostatus Páll-Gergely n. sp., Dicharax micropolitus Páll-Gergely & Hunyadi n. sp., Dicharax robustus Páll-Gergely & Hunyadi, n. sp., Metalycaeus (?) awalycaeoides Páll-Gergely & Hunyadi n. sp., Metalycaeus (?) ibex Páll-Gergely & Hunyadi n. sp., Metalycaeus laosensis Páll-Gergely n. sp., Metalycaeus oharai Páll-Gergely & Hunyadi n. sp., Metalycaeus (?) okuboi Páll-Gergely & Hunyadi, n. sp. A total of twelve names are synonymised with valid species. In this revision we payed special attention to conchological characters hitherto neglected, such as the fine sculpture of the embryonic whorls and the fine structure of the microtunnels along the breathing tube. We described the radula and penis morphology of five Dicharax species.

A new diplommatinid genus and two new species from the Philippines (Gastropoda, Caenogastropoda, Cyclophoroidea).

A new diplommatinid genus, Luzonocoptis Páll-Gergely & Hunyadi, gen. n. is erected for two new species, Luzonocoptis antenna Páll-Gergely & Hunyadi, sp. n. and L. angulata Páll-Gergely & Hunyadi, sp. n. Both species inhabit the northeastern part of Luzon Island, Philippines. The genus Luzonocoptisgen. n. is mostly characterized by a very slender shell with 14-18 whorls, a strongly expanded peristome, an interrupted, weak columellar lamella, the absence of any additional plicae or lamellae, and a rachidian tooth having five cusps.

Seven new hypselostomatid species from China, including some of the world's smallest land snails (Gastropoda, Pulmonata, Orthurethra).

Seven new species of Hypselostomatidae are described from the Chinese province Guangxi: Angustopila dominikae Páll-Gergely & Hunyadi, sp. n., Angustopila fabella Páll-Gergely & Hunyadi, sp. n., Angustopila subelevata Páll-Gergely & Hunyadi, sp. n., Angustopila szekeresi Páll-Gergely & Hunyadi, sp. n., Hypselostoma socialis Páll-Gergely & Hunyadi, sp. n., Hypselostoma lacrima Páll-Gergely & Hunyadi, sp. n. and Krobylos sinensis Páll-Gergely & Hunyadi, sp. n. The latter species is reported from three localities. All other new species are known only from the type locality. Specimens nearly identical to the type specimens of Angustopila huoyani Jochum, Slapnik & Páll-Gergely, 2014 were found in a cave in northern Guangxi, 500 km from the type locality. Adult individuals of Angustopila subelevata sp. n. (shell height = 0.83-0.91 mm, mean = 0.87 mm) and Angustopila dominikae sp. n. (shell height of the holotype = 0.86 mm) represent the smallest known members of the Hypselostomatidae, and thus are amongst the smallest land snails ever reported. We note that Pyramidula laosensis Saurin, 1953 might also belong to Krobylos. Paraboysidia neglecta van Benthem Jutting, 1961, which was previously included in Angustopila, is classified in Hypselostoma.

A new Chinese species of Eostrobilops Pilsbry, 1927 with a checklist of Eostrobilops and Enteroplax Gude, 1897 species (Gastropoda, Pulmonata, Strobilopsidae).

Eostrobilopshumicolus Páll-Gergely & Hunyadi, sp. n. is described from Guangxi Province, China. It is characterized by the combination of a small shell (diameter: 2.3-2.4 mm), strongly ribbed dorsal surface, an infraparietal lamella not reaching the callus, and long basal folds. The new species is found approximately 500 and 800 km from the two nearest species Eostrobilopsinfrequens (northern Vietnam), and Eostrobilopsdiodontina (Hunan, China), respectively. A checklist of extant Eostrobilops Pilsbry, 1927 and Enteroplax Gude, 1899 species is provided. Enteroplaxyaeyamensis Habe & Chinen, 1974, Enteroplaxkanjiokuboi Minato & Tada, 1992 and Enteroplaxtaiwanica Minato & Tada, 1992 are moved to the genus Eostrobilops because of the lack of an elevated parietal callus and a peripheral thread. A map showing all Eostrobilops records is provided.

Revision of the genus Pseudopomatias and its relatives (Gastropoda: Cyclophoroidea: Pupinidae).

The present paper revises all species that have been assigned to Pseudopomatias Möllendorff, 1885 and Nodopomatias Gude, 1921. The following new species are described: Pseudopomatias abletti Páll-Gergely, n. sp. (northeastern India), Pseudopomatias harli Páll-Gergely, n. sp. (northeastern India), Pseudopomatias linanprietoae Páll-Gergely n. sp. (Laos), Pseudopomatias maasseni Páll-Gergely & Hunyadi, n. sp. (Vietnam and China), Pseudopomatias nitens Páll-Gergely n. sp. (Vietnam), Pseudopomatias prestoni Páll-Gergely, n. sp. (northeastern India), Pseudopomatias reischuetzi Páll-Ger-gely, n. sp. (north-eastern India), Pseudopomatias shanensis Páll-Gergely n. sp. (Myanmar) and Pseudopomatias sophiae Páll-Gergely, n. sp. (Vietnam). Pseudopomatias fulvus is moved to the synonymy of P. amoenus. Csomapupa n. gen. is erected for Pseudopomatias grandis and P. luyorensis. Another new genus, Vargapupa is erected with two species, namely Vargapupa biheli Páll-Gergely, n. sp. (Vietnam) and V. oharai Páll-Gergely, n. sp. (Laos). Both new genera are probably closely related to Pseudopomatias and Nodopomatias. All the currently available type specimens of species in these groups are figured. Anatomical information of P. eos and DNA sequence data of two Pseudopomatias species indicate that the genus is a member of the family Pupinidae. The other pre-existing hypothesis, namely that Pseudopomatias is a member of the Cochlostomatidae, is not supported by our results.

Systematics of the family Plectopylidae in Vietnam with additional information on Chinese taxa (Gastropoda, Pulmonata, Stylommatophora).

Vietnamese species from the family Plectopylidae are revised based on the type specimens of all known taxa, more than 600 historical non-type museum lots, and almost 200 newly-collected samples. Altogether more than 7000 specimens were investigated. The revision has revealed that species diversity of the Vietnamese Plectopylidae was previously overestimated. Overall, thirteen species names (anterides Gude, 1909, bavayi Gude, 1901, congesta Gude, 1898, fallax Gude, 1909, gouldingi Gude, 1909, hirsuta Möllendorff, 1901, jovia Mabille, 1887, moellendorffi Gude, 1901, persimilis Gude, 1901, pilsbryana Gude, 1901, soror Gude, 1908, tenuis Gude, 1901, verecunda Gude, 1909) were synonymised with other species. In addition to these, Gudeodiscushemmeni sp. n. and Gudeodiscusmessageriraheemi ssp. n. are described from north-western Vietnam. Sixteen species and two subspecies are recognized from Vietnam. The reproductive anatomy of eight taxa is described. Based on anatomical information, Halongella gen. n. is erected to include Plectopylisschlumbergeri and Plectopylisfruhstorferi. Additionally, the genus Gudeodiscus is subdivided into two subgenera (Gudeodiscus and Veludiscus subgen. n.) on the basis of the morphology of the reproductive anatomy and the radula. The Chinese Gudeodiscusphlyariuswerneri Páll-Gergely, 2013 is moved to synonymy of Gudeodiscusphlyarius. A spermatophore was found in the organ situated next to the gametolytic sac in one specimen. This suggests that this organ in the Plectopylidae is a diverticulum. Statistically significant evidence is presented for the presence of calcareous hook-like granules inside the penis being associated with the absence of embryos in the uterus in four genera. This suggests that these probably play a role in mating periods before disappearing when embryos develop. Sicradiscusmansuyi is reported from China for the first time.