Analyses of the bioluminescence mechanism in the land snail, Quantula weinkauffiana.

The mechanism of bioluminescence in the luminous land snails remains largely unknown. Here, we analyzed basic biochemical properties of the luminous land snail, Quantula weinkauffiana. The luminescence activity was extracted from the light organ located near the mouth using a neutral buffer containing detergent. The reaction of the crude buffer extract was triggered by the addition of only hydrogen peroxide (H2O2). These results are inconsistent with the single precedent report on the bioluminescence in the Quantula striata by Shimomura and Haneda in 1986, in which the luminescence of the buffer extract (without detergent) from the light organ was induced by the coaddition of three indispensable components H2O2, ferrous ion, and 2-mercaptoethanol. Based on the present findings, we suggested that an insoluble photoprotein is involved in the bioluminescence of the luminous land snails and the luminescence reaction is simply triggered by H2O2.

De novo genome assembly and transcriptome sequencing in foot and mantle tissues of Megaustenia siamensis reveals components of adhesive substances.

The semislug Megaustenia siamensis, commonly found in Thailand, is notable for its exceptional capacity to produce biological adhesives, enabling it to adhere to tree leaves even during heavy rainfall. In this study, we generated the first reference genome for M. siamensis using a combination of three sequencing technologies: Illumina's short-read, Pac-Bio's HIFI long-read, and Hi-C. The assembled genome size was 2593 billion base pairs (bp), containing 34,882 protein-coding genes. Our analysis revealed positive selection in pathways associated with the ubiquitin-proteasome system. Furthermore, RNA sequencing of foot and mantle tissues unveiled the primary constituents of the adhesive, including lectin-like proteins (C-lectin, H-lectin, and C1q) and matrilin-like proteins (VWA and EGF). Additionally, antimicrobial peptides were identified. The comprehensive M. siamensis genome and tissue-specific transcriptomic data provided here offer valuable resources for understanding its biology and exploring potential medical applications.

Contributions of a small collection of terrestrial microsnails (Pupilloidea, Hypselostomatidae) from Myanmar with description of three new species.

Land snails were collected for the project 'Conserving Myanmar's Karst Biodiversity' from the limestone karsts in Mon, Kayin, and Shan states and in the regions of Tanintharyi and Mandalay between 2015 and 2017, through cooperation with Fauna and Flora International (FFI) and the Forestry Department of Myanmar. Here, we report on a portion of the collection, and list 17 species from seven genera of the Hypselostomatidae microsnails. Three new species from two genera are described as Bensonellataiyaiorum Tongkerd & Panha, sp. nov., B.lophiodera Tongkerd & Panha, sp. nov., and Gyliotrachelaaunglini Tongkerd & Panha, sp. nov. All new species are known only from the type locality in Shan State (Bensonella) and Kayin State (Gyliotrachela). A new combination of Acinolaemusdayanum and three newly recorded species, namely A.cryptidentatus, B.anguloobtusa and G.hungerfordiana are discussed. The low morphological variability of the widely distributed G.hungerfordiana is discussed, and two species are proposed for formal synonymisation. Constituting the first records for Myanmar, five species of Bensonella and two species of Acinolaemus were collected.

A new discovery of the bioluminescent terrestrial snail genus Phuphania (Gastropoda: Dyakiidae).

The mysterious world of the bioluminescent molluscs in terrestrial ecosystems is mesmerizing, but Quantula striata was previously the only terrestrial mollusc known to be luminescent. Here, we document the new discovery of bioluminescence in four land snails, namely Phuphania crossei, P. globosa, P. carinata, and P. costata. Our observations establish clearly that these four species of Phuphania produce a continuous greenish light from the light-emitting cells located within the mantle and the foot, and that its bright luminescence is intracellular and is not due to any luminous secretion. Although both Quantula and Phuphania can produce a green light, the luminescence patterns are different. The luminescence displayed by Quantula is rhythmical blinking or flashing, while Phuphania glows continuously. In addition, the bioluminescence in Q. weinkauffiana is confirmed, which is similar to that in the related species, Q. striata.

Systematic revision of the snorkel snail genus Rhiostoma Benson, 1860 (Gastropoda, Caenogastropoda, Cyclophoridae) with descriptions of new species.

The snorkel snail genus Rhiostoma Benson, 1860 is comprised of terrestrial cyclophorid snails with wide-ranging species diversity and radiation in Southeast Asia. The typical characters of the genus are a depressed shell, a detached and descending portion of the last whorl with a distinctive peristomal breathing device attached, and a calcareous cup-shaped operculum. Herein, we have revised the systematics of extant species based on shell morphology combined with COI barcoding. From these thirty recognised species, twelve are described as new to science: R. ? amarapuraensesp. nov., R.anceyisp. nov., R.breviocollarsp. nov., R.ebenozosterasp. nov., R.cheliopegmasp. nov., R.furfurosumsp. nov., R.gnomus, sp. nov., R.lannaensesp. nov., R.laoensesp. nov., R.platymorphasp. nov., R.rhothonotaphrosasp. nov., and R.tigrinasp. nov. All conchological characters are provided via illustrations of type specimens and living snails, and descriptions of the shells and radulae. Phylogenetic analysis based on partial COI gene sequences strongly supports the designated morphospecies and a monophyletic Rhiostoma, confirming that all pterocyclinid snails with a calcareous, cup-shaped operculum belong to the same clade. A high intra-specific divergence was observed in R.jalorensis and R.housei populations from locations in close proximity, suggesting a lower dispersal and higher level of isolation. The low inter-specific divergence found in R.hainesi, R.samuiense, R.asiphon, and R.rhothonotaphrosasp. nov. supports their recent diversification and local adaptation, and is congruent with their marked morphological differences. Finally, nine formerly Rhiostoma-placed species were reclassified into either the genus Cyclotus or the genus Opisthoporus.

Stasis and diversity in living fossils: Species delimitation and evolution of lingulid brachiopods.

The Lingulidae are often considered living fossils, because they have shown little morphological change since the Paleozoic. Limited morphological variation has also made the taxonomic study of living lingulids challenging. We investigated species diversity and phylogenetic relationships of extant lingulids and show that they are substantially more diverse than realized, demonstrating that morphological stasis was commonly accompanied by speciation. Species delimitation based on cytochrome c oxidase subunit I (COI) gene sequences from 194 specimens sampled from East Asia, Australia, Oceania, and the Americas suggested 14-22 species in the lingulids (9-17 species in Lingula and 4-5 species in Glottidia), in contrast to the 11-12 species currently recognized globally in the family. Four-gene phylogenetic analyses supported the sister relationship between Lingula and Glottidia. Within Lingula, L. adamsi, which possesses large, brownish shells, was recovered as sister to all remaining Lingula species, which have more or less greenish shells. Within the greenish Lingula clade, the 'L. anatina' complex was sister to the clade that includes the 'L. reevei' complex. The 'L. anatina' complex was further separated into two major clades with partly separate ranges centered on (i) temperate East Asia, and (ii) the tropical west-central Pacific. Within Glottidia, Pacific species were nested within Atlantic species. Time-calibrated phylogenetic analyses suggested that Lingula likely originated in the early Cretaceous contrary to a previously proposed hypothesis advocating a Cenozoic origin. The separation of Lingula and Glottidia appears to date from the Mesozoic, not from the Carboniferous, contrary to a previous hypothesis. Overall, our results uncovered substantial cryptic diversity in lingulids, which will form the basis for conservation and further taxonomic revision.

Integrative taxonomic revision of the land snail genus Sarika Godwin-Austen, 1907 in Thailand, with descriptions of nine new species (Eupulmonata, Ariophantidae).

Members of the land snail genus SarikaGodwin-Austen 1907 are superficially similar and difficult to differentiate by their shell morphology so that their species limits are still unclear. In order to resolve the taxonomy of this group, a phylogenetic reconstruction of Sarika is presented, based on morphological and anatomical characters, as well as on partial sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene. In total, 23 species of Sarika are recognised in Thailand, and nine species are new to science, namely S. caligina Pholyotha & Panha, sp. nov., S. gratesi Pholyotha & Panha, sp. nov., S. inferospira Pholyotha & Panha, sp. nov., S. lactospira Pholyotha & Panha, sp. nov., S. megalogyne Pholyotha & Panha, sp. nov., S. melanospira Pholyotha & Panha, sp. nov., S. pellosa Pholyotha & Panha, sp. nov., S. solemi Pholyotha & Panha, sp. nov., and S. subheptagyra Pholyotha & Panha, sp. nov. Results from genital examination and COI analyses confirm the monophyly of Sarika and its species. The intra- and inter-specific genetic distances of Sarika were 0-3.7% and 4.6-12.0%, respectively. Colour images of the living adults, shell, and genitalia along with SEM images of the spermatophore and radula are given. In addition, an identification key and a geographical distribution map of Sarika species are provided.

Phylogenetics and species delimitations of the operculated land snail Cyclophorus volvulus (Gastropoda: Cyclophoridae) reveal cryptic diversity and new species in Thailand.

Recent conceptual and practical advances in phylogenetic species delimitation have enabled progressively robust biodiversity studies. Delimiting species in widespread taxa is an intriguing problem; the edible operculated land snail Cyclophorus volvulus (Müller, 1774) is a good example since it shows a high degree of shell and color variation along with a widespread distribution throughout Thailand. Taxonomic boundaries for C. volvulus were examined and clarified using a combined morphological and phylogenetic approach, the latter of which was based on both nuclear and mitochondrial gene sequences. Moreover, three species delimitation analyses were applied: Poisson tree processes (PTP), automatic barcode gap discovery (ABGD), and generalized mixed Yule-coalescent (GMYC). All phylogenetic trees revealed that C. volvulus was polyphyletic and comprised of three clades that coincided with their geographic distribution. The three species delimitation analyses concurred with the phylogenies and formed at least three groups. According to the results, C. volvulus s.l., as currently recognized, consists of three distinct species in Thailand: C. volvulus s.s., C. occultus sp. nov., and C. borealis sp. nov., which are described herein. Moreover, several of these highly distinct C. volvulus evolutionarily significant units (ESU) are likely to require urgent conservation attention.

A taxonomic review of the centipede genus Scolopendra Linnaeus, 1758 (Scolopendromorpha, Scolopendridae) in mainland Southeast Asia, with description of a new species from Laos.

The centipede genus Scolopendra in mainland Southeast Asia is reviewed taxonomically based on morphological characters, informed by a molecular phylogenetic analysis using sequences from three mitochondrial and nuclear genes (COI, 16S rRNA and 28S rRNA). Eight nominal species of Scolopendra, namely Scolopendra morsitans Linnaeus, 1758, Scolopendra subspinipes Leach, 1816, Scolopendra dehaani Brandt, 1840, Scolopendra multidens Newport, 1844, Scolopendra calcarata Porat, 1876, Scolopendra japonica Koch, 1878, Scolopendra pinguis Pocock, 1891, and Scolopendra dawydoffi Kronmüller, 2012, are redescribed together with some revision of type materials. Geographical variation in each species has been compiled with reference to samples that span their distribution ranges in Southeast Asia and some parts of neighbouring areas such as East Asia, the Indian Ocean, and Africa. Comparative study of traditional taxonomic characters from external morphology provides further information to distinguish some closely related species. Scolopendra cataracta Siriwut, Edgecombe & Panha, sp. n., is described from the southern part of Laos, with additional records in Thailand and Vietnam. The phylogenetic framework for Southeast Asian Scolopendra recognizes Scolopendra calcarata + Scolopendra pinguis, Scolopendra morsitans, and a Scolopendra subspinipes group that unites the other six species as the main clades. Within the Scolopendra subspinipes group, two monophyletic groups can be distinguished by having either slender or short, thick ultimate leg prefemora and different numbers of apical spines on the coxopleuron. Scolopendra arborea Lewis, 1982, is placed in subjective synonymy with Scolopendra dehaani. A survey of external morphology of the genital segments confirms its potential for improving species identification in Scolopendra. Some observations on biology and behaviour are recorded based on field surveys in this area.

Illustrated type catalogue of Amphidromus Albers, 1850 in the Natural History Museum, London, and descriptions of two new species.

The collection of the Southeast Asian tree snail genus Amphidromus Albers, 1850 at the Natural History Museum, London includes more than 100 lots of type specimens representing 85 name-bearing types, 9 paratypes and 6 paralectotypes, and one nomen nudum. Lectotypes are here designated for Amphidromuscambojiensis, Amphidromusperakensisglobosus, Amphidromuscolumellarisgloriosa, Amphidromusmaculiferusinflata, Amphidromuslepidus, Amphidromussinistralislutea, Amphidromusmoniliferus, Amphidromusmaculiferusobscura, Amphidromussinistralisrosea and Amphidromussinensivicaria. In addition, the missing types of A.A. Gould were discovered and their type status is discussed. A complete catalogue of these types, including colour photographs is provided for the first time. After examining these type specimens, two new Amphidromus species, Amphidromus (Syndromus) globonevilli Sutcharit & Panha, sp. n. and Amphidromus (Syndromus) principalis Sutcharit & Panha, sp. n. were recognized and are described herein.

First record of the African-Indian centipede genus Digitipes Attems, 1930 (Scolopendromorpha: Otostigminae) from Myanmar, and the systematic position of a new species based on molecular phylogenetics.

The first Southeast Asian record of the scolopendrid centipede Digitipes Attems, 1930, has been collected and analyzed based on a new species from Myanmar, males possessing a distomedial process on the ultimate leg femur that is diagnostic of the genus. Digitipes kalewaensis n. sp., described herein, is distinguished from other members of Digitipes by its 2.5 to 2.7 dorsally glabrous antennal articles, an unusually long basal suture on the tooth-plates, absence of a lateral spine on the coxopleural process, and a lack of median and dorso-median spines on the ultimate leg prefemur. Maximum likelihood and Bayesian analyses of two molecular markers (mitochondrial COI and 16S rRNA) supported the proposal of a new species from Myanmar. The phylogenetic tree identifies Digitipes barnabasi from the Western Ghats, India, in a polytomy with members of other genera of Otostigminae (Otostigmus, Ethmostigmus and Rhysida) and a robust Indian-Burmese Digitipes clade in which D. kalewaensis n. sp. is resolved as sister group to a clade composed of most Indian species. Available molecular dates for the diversification of Indian Digitipes are consistent with introduction of the genus into SE Asia when the Indian subcontinent made contact with Myanmar in the early Palaeogene.

An annotated catalogue of type specimens of the land snail genus Cyclophorus Monfort, 1810 (Caenogastropoda, Cyclophoridae) in the Natural History Museum, London.

The collection of land caenogastropod snails in the genus Cyclophorus Monfort, 1810 housed in the Natural History Museum, London (NHM), includes 52 type lots. Lectotypes have been designated for 43 available species-level names to stabilize existing nomenclature, two previously designated lectotype, two holotypes, one paratype, one syntype, one possible syntype and two paralectotypes are also listed. A complete catalogue of the Cyclophorus types in NHM, London is provided for the first time.

Phylogenetic relationships of the operculate land snail genus Cyclophorus Montfort, 1810 in Thailand.

Operculate land snails of the genus Cyclophorus are distributed widely in sub-tropical and tropical Asia. Shell morphology is traditionally used for species identification in Cyclophorus but their shells exhibit considerable variation both within and between populations; species limits have been extremely difficult to determine and are poorly understood. Many currently recognized species have discontinuous distributions over large ranges but geographical barriers and low mobility of snails are likely to have led to long periods of isolation resulting in cryptic speciation of allopatric populations. As a contribution towards solving these problems, we reconstructed the molecular phylogeny of 87 Cyclophorus specimens, representing 29 nominal species (of which one was represented by four subspecies), plus three related out-group species. Molecular phylogenetic analyses were used to investigate geographic limits and speciation scenarios. The analyses of COI, 16S rRNA and 28S rRNA gene fragments were performed using neighbour-joining (NJ), maximum likelihood (ML), and Bayesian inference (BI) methods. All the obtained phylogenetic trees were congruent with each other and in most cases confirmed the species level classification. However, at least three nominate species were polyphyletic. Both C. fulguratus and C. volvulus appear to be species complexes, suggesting that populations of these species from different geographical areas of Thailand are cryptic species. C. aurantiacus pernobilis is distinct and likely to be a different species from the other members of the C. aurantiacus species complex.

The semi-aquatic freshwater earthworms of the genus Glyphidrilus Horst, 1889 from Thailand (Oligochaeta, Almidae) with re-descriptions of several species.

The semi-aquatic freshwater earthworm genus Glyphidrilus Horst, 1889 from Thailand was investigated based on extensive recent collecting. The species in this genus were characterized by their external and internal morphological characters of the location of wings, genital openings, genital organ structures and their locations, as well as the dimensions of body length and number of segments. Several type specimens were compared with both previous and newly collected materials. Ten new species are described from several river systems in Thailand; as Glyphidrilus borealis sp. n., Glyphidrilus chaophraya sp. n., Glyphidrilus chiensis sp. n., Glyphidrilus huailuangensis sp. n., Glyphidrilus kratuensis sp. n., Glyphidrilus quadratus sp. n., Glyphidrilus trangensis sp. n., Glyphidrilus wararamensis sp. n., Glyphidrilus vangthongensis sp. n. and Glyphidrilus vesper sp. n. Each species is endemic to a single river system. All 26 previously described species are re-described, and eight lectotypes have been designated. An identification key and a morphological comparison summary are provided.

New earthworm species of the genus Amynthas Kinberg, 1867 from Thailand (Clitellata, Oligochaeta, Megascolecidae).

Four new species of terrestrial earthworms from the zebrus-group in the genus Amynthas Kinberg, 1867, are described from Nan province, north Thailand: Amynthas phatubensissp. n., from Tham Pha Tub Arboretum, Amynthas tontongsp. n., from Tontong Waterfall, Amynthas borealissp. n., from Chaloemprakiat district, and Amynthas srinansp. n., from Srinan National Park.After comparing with the two closely related Laos species Amynthas chandyi Hong, 2008 and Amynthas namphouinensis Hong, 2008, the four new species show clear morphological differences, and also it is confirmed that there are no previous records of the species described here. Amynthas phatubensissp. n. is the largest (longest) sized of these earthworms and is the only species that lives in limestone habitats. The genital characters are different among them and also from the two Laotian species. Molecular systematics would be a good method for further analysis of the diversity and species boundaries in SE Asian Amynthas.