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Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation. ispartof: ECOLOGY LETTERS vol:25 issue:2 pages:255-263 ispartof: location:England status: published

Background Anthropogenic factors potentially affect observed biogeographical patterns in population genetics, but the effects of ancient human activities on the original patterns created by natural processes are unknown. Sinotaia quadrata, a widely distributed freshwater snail species in East Asia, was used to investigate this issue. It is unclear whether S. quadrata in Japan was introduced from China and how different human uses and varying geographic patterns affect the contemporary population genetics between the two regions. Thus, we investigated the demography of S. quadrata and detected its genetic structure in Japan and continental East Asia. Results Sinotaia quadrata populations first naturally migrated from continental East Asia to Japan, which is associated with the ancient period in Japanese geohistory (about 70,000 years ago). They were then artificially introduced in association with agriculture expansion by human movements in two recent periods (about 8,000 and 1,200 years ago). Populations in different parts of Japan have their own sources. Natural migration in the ancient period and artificial introduction in the recent period suggest that the population distribution is affected by both the geohistory of East Asia and the history of human expansion. In the background of the historical migration and introduction, contemporary populations in the two regions show different genetic patterns. Population divergence levels were significantly correlated with geographical patterns in Japan and significantly correlated with human interventions variables in continental East Asia, suggesting that long‐term geographical isolation is likely the major factor that shaped the contemporary population genetics in Japan, while modern human uses are likely the major factor in continental East Asia. Conclusions Our preliminary results show a complex demography and unusual genetic patterns in the contemporary populations for a common freshwater snail and are of significance to determine the historical formation and contemporary patterns of biogeography in Japan and continental East Asia., We document the population history and genetic history of the common freshwater snail Sinotaia quadrata in Japan and continental East Asia. Natural migration in the ancient period and artificial introduction in the recent period suggest that the population distribution is affected by both the geohistory of East Asia and the history of human expansion. Long‐term geographical isolation is likely the major factor that shaped the genetic structure of contemporary populations in Japan, while modern human uses are likely the major factor in continental East Asia.

Endemic organisms of ancient lakes have been studied as models to understand processes of speciation and adaptive radiation. However, it remains unclear how ancient lakes play roles in genetic and phenotypic diversity of freshwater mollusks. In the present study, we focus on viviparid freshwater snails in the ancient lakes of East and Southeast Asia (Japan and China) to address this question. Using molecular phylogenetic analyses based on mitochondrial (COI, 16S) and nuclear genes (18S, 28S, H3), we show that patterns of species diversification in viviparid lineages. Colonization to ancient lakes occurred independently in China and Japan at least four times, with subsequent diversification into more than two species within each lake group. Morphological analyses of fossil related viviparids suggest parallel phenotypic evolution occurred in the different lakes and ages. Each lake contained a single lineage which was phenotypically diversified relative to those from other sites. Using genome-wide SNPs obtained by MIG-seq, we also examined the genetic structure of three Japanese viviparids, including two endemic species of ancient Lake Biwa. The results suggest that these two species diversified from the population of the third species living in wetlands surrounding the lake. These findings suggest that rapid diversification of lineages and phenotypic divergence can occur in ancient lakes compared to other habitats. Formation of large lakes probably promotes speciation and phenotypic divergence as a result of adaptation into different microhabitats. High numbers of ancient lakes could be a driver of species diversity in Asian viviparid snails.

Accurate species identification is of primary importance in ecology and evolutionary biology. For a long time, the unionid mussels Beringiana and Sinanodonta have puzzled researchers trying to unravel their diversity because of their poorly discernible morphologies. A recent study conducted species delineation of unionid mussels based on mitochondrial DNA variation, opening up a new avenue to grasp species diversity of the mussels. However, mtDNA-based classification may not align with species boundaries because mtDNA is prone to introgression and incomplete lineage sorting that cause discordance between species affiliation and gene phylogeny. In this study, we evaluated the validity of the mtDNA-based classification of unionid mussels Beringiana and Sinanodonta in Japan using mitochondrial sequence data, double digest restriction site-associated DNA library (ddRAD) sequencing, and morphological data. We found significant inconsistencies in the mitochondrial and nuclear DNA phylogenies, casting doubt on the reliability of the mtDNA-based classification in this group. In addition, nuclear DNA phylogeny revealed that there are at least two unionid lineages hidden in the mtDNA phylogeny. Although molecular dating technique indicates that Beringiana and Sinanodonta diverged35 million years ago, their shell morphologies are often indistinguishable. Specifically, morphological analyses exhibited the parallel appearance of nearly identical ball-like shell forms in the two genera in Lake Biwa, which further complicates species identification and the morphological evolution of unionid mussels. Our study adds to a growing body of literature that accurate species identification of unionid mussels is difficult when using morphological characters alone. Although mtDNA-based classification is a simple and convenient way to classify unionid mussels, considerable caution is warranted for its application in ecological and evolutionary studies.

The taxonomy of species in the caenogastropod genus Sinotaia (Viviparidae: Bellamyinae) has been a complex and controversial issue since the 19th century. Sinotaia quadrata, the type species of Sinotaia, comprises many named forms and transitions between them, and the taxonomic validity of some species similar to S. quadrata also requires clarification. To clarify relationships in this common and significant member of the freshwater benthos, we reconstructed a phylogeny for species related to S. quadrata based on the 16S rRNA and cytochrome c oxidase subunit I genes to test which classifications are robust using modern data and interpretation. We also compared the shell outline morphology of type material of most species in the genus Sinotaia from the original literature. The combination of phylogenetic and shape variance data suggests that seven currently recognized species of Sinotaia should be synonymized with S. quadrata. We used microsatellite markers and landmark-based geometric morphometric analysis to examine the genetic differentiation and shell shape variation of S. quadrata populations in both China and Japan. Genetic and shape variations were not congruent, suggesting that minor variations in shell shape do not indicate distinct Sinotaia species. Shell shape variation shows no clear separations and shows environmental plasticity. Using data on molecular phylogenetics, genetic diversity and shell morphology, we provide a more inclusive species concept for S. quadrata. This provides a basis to formally revise this taxon and the seven closely related nominal species that are widely distributed in China and East Asia.

Revealing the species and lineage diversity of a taxon is important for many biological studies of wildlife. In recent decades, DNA-based approaches have been widely utilised to elucidate the diversity of taxa, especially those that are difficult to distinguish based on morphological traits. This study focused on freshwater clams (Sphaeriidae) in Japan, a biodiversity hotspot of freshwater molluscs. Molecular phylogenetic approaches, including divergence time estimation, species delimitation, rarefaction, and biogeographic area estimation, were used to reveal the nature of the species diversity and its formation process, which are largely unknown. Our delimitation and rarefaction analyses suggest that Japanese sphaeriid clams consist of at least 18 delimitated lineages. This lineage diversity is relatively high compared to other Japanese freshwater molluscs, and in addition, the majority of the Japanese lineage appears to have high endemicity despite the possibility of long-distance dispersal in sphaeriid clams. Our biogeographical analyses suggest that this diversity may be due to the combination of colonisation, during the period when Japan was connected to the continent, and the relatively recent dispersal. Our results highlight the overlooked biodiversity of Japan and provide a basis for further Japanese sphaeriid research, including conservation perspectives.

Background Islands have traditionally been the centre of evolutionary biological research, but the dynamics of immigration and differentiation at continental islands have not been well studied. Therefore, we focused on the Japanese archipelago, the continental islands located at the eastern end of the Eurasian continent. While the Japanese archipelago is characterised by high biodiversity and rich freshwater habitats, the origin and formation mechanisms of its freshwater organisms are not clear. In order to clarify the history of the planorbid gastropod fauna, we conducted phylogenetic analysis, divergence time estimation, ancestral state reconstruction, and lineage diversity estimations. Results Our analyses revealed the formation process of the planorbid fauna in the Japanese archipelago. Most lineages in the Japanese archipelago have closely related lineages on the continent, and the divergence within the Japanese lineages presumably occurred after the late Pliocene. In addition, each lineage is characterised by different phylogeographical patterns, suggesting that immigration routes from the continent to the Japanese archipelago differ among lineages. Furthermore, a regional lineage diversity plot showed that the present diversity in the Japanese archipelago potentially reflects the differentiation of lineages within the islands after the development of the Japanese archipelago. Conclusions Although additional taxon sampling and genetic analysis focused on each lineage are needed, our results suggest that immigration from multiple routes just prior to the development of the Japanese archipelago and subsequent diversification within the islands are major causes of the present-day diversity of the Japanese planorbid fauna. Electronic supplementary material The online version of this article (10.1186/s12862-018-1273-3) contains supplementary material, which is available to authorized users.

Currently, many species are facing the risk of extinction, as it one of the most serious conservation issues. Many conservation programs have evolved to prevent species extinction; however, developing these strategies may prove to be difficult for the species itself, which includes different cryptic species. In this paper, we document the invasion of non-native cryptic species of ancylin limpets, Ferrissia californica, with a molecular phylogenetic analysis. Three species (F. nipponica, F. japonica, Gundlachia japonica) have been described as native, whereas the present analysis shows that most of them are actually non-native F. californica, having been introduced from North America and spreading throughout Japan. In addition, we found a few subpopulations of the cryptic native species of the ancylin limpets, though the native limpet species is very rare, and has limited distribution. The conservation status assigned to ancylin limpets on the Japanese red list is problematic, because F. japonica is listed as an endangered species. All individuals identified as F. japonica are of F. californica, so the current red list treats invasive non-native species as endangered. Reassessment of the conservation status of native species and an estimation of the impact of non-native species is required to better delineate these limpet species by genetic markers.

Freshwater mussels are declining globally, and effective conservation requires prioritizing research and actions to identify and mitigate threats impacting mussel species. Conservation priorities vary widely, ranging from preventing imminent extinction to maintaining abundant populations. Here, we develop a portfolio of priority research topics for freshwater mussel conservation assessment. To address these topics, we group research priorities into two categories: intrinsic or extrinsic factors. Intrinsic factors are indicators of organismal or population status, while extrinsic factors encompass environmental variables and threats. An understanding of intrinsic factors is useful in monitoring, and of extrinsic factors are important to understand ongoing and potential impacts on conservation status. This dual approach can guide conservation status assessments prior to the establishment of priority species and implementation of conservation management actions., La lista completa de autores de este trabajo puede verse en el archivo asociado., Facultad de Ciencias Naturales y Museo

Two Unionida (freshwater mussel) families are present in the Northern Hemisphere; the Margaritiferidae, representing the most threatened of unionid families, and the Unionidae, which include several genera of unresolved taxonomic placement. The recent reassignment of the poorly studied Lamprotula rochechouartii from the Unionidae to the Margaritiferidae motivated a new search for other potential species of margaritiferids from members of Gibbosula and Lamprotula. Based on molecular and morphological analyses conducted on newly collected specimens from Vietnam, we here assign Gibbosula crassa to the Margaritiferidae. Additionally, we reanalyzed all diagnostic characteristics of the Margaritiferidae and examined museum specimens of Lamprotula and Gibbosula. As a result, two additional species are also moved to the Margaritiferidae, i.e. Gibbosula confragosa and Gibbosula polysticta. We performed a robust five marker phylogeny with all available margaritiferid species and discuss the taxonomy within the family. The present phylogeny reveals the division of Margaritiferidae into four ancient clades with distinct morphological, biogeographical and ecological characteristics that justify the division of the Margaritiferidae into two subfamilies (Gibbosulinae and Margaritiferinae) and four genera (Gibbosula, Cumberlandia, Margaritifera, and Pseudunio). The systematics of the Margaritiferidae family is redefined as well as their distribution, potential origin and main biogeographic patterns., This work was supported by FCT – Foundation for Science and Technology, Project 3599 – Promote the Scientific Production and Technological Development and Thematic 3599-PPCDT by FEDER as part of the project FRESHCO: Multiple implications of invasive species on Freshwater Mussel co-extinction processes (contract: PTDC/ AGRFOR/1627/2014). FCT also supported MLL (SFRH/BD/115728/2016) and EF (SFRH/BPD/108445/2015). The Russian Ministry of Education and Science (project no. 6.2343.2017/4.6), the Federal Agency for Scientific Organizations (project no. 0409-2015-0143), the Presidium of the Russian Academy of Sciences (scientific program no. 52), and the Russian Foundation for Basic Research, RFBR (project no. 17-45-290066) supported INB, MYG, AVK, and IVV. The Nagao Natural Environment Foundation (NEF) supported for VTD research project “The study of Unionoida biodiversity and conservation status in Bang and Ky Cung River basins in Northeast Vietnam”.

Phylogenetic incongruence has frequently been encountered among different molecular markers. Recent progress in molecular phylogenomics has provided detailed and important information for evolutionary biology and taxonomy. Here we focused on the freshwater viviparid snails (Cipangopaludina chinensis chinensis and C. c. laeta) of East Asia. We conducted phylogenetic analyses and divergence time estimation using two mitochondrial markers. We also performed population genetic analyses using genome-wide SNPs. We investigated how and which phylogenetic patterns reflect shell morphology. The results showed these two species could be separated into four major mitochondrial clades, whereas the nuclear clusters supported two groups. The phylogenetic patterns of both mtDNA and nDNA largely reflected the geographical distribution. Shell morphology reflected the phylogenetic clusters based on nDNA. The findings also showed these two species diversified in the Pliocene to early Pleistocene era, and occurred introgressive hybridisation. The results also raise the taxonomic issue of the two species.

WOS: 000388059500017, 27621130, Freshwater mussels of the order Unionida are key elements of freshwater habitats and are responsible for important ecological functions and services. Unfortunately, these bivalves are among the most threatened freshwater taxa in the world. However, conservation planning and management are hindered by taxonomic problems and a lack of detailed ecological data. This highlights the urgent need for advances in the areas of systematics and evolutionary relationships within the Unionida. This study presents the most comprehensive phylogeny to date of the larger Unionida family, i.e., the Unionidae. The phylogeny is based on a combined dataset of 1032 bp (COI + 28S) of 70 species in 46 genera, with 7 of this genera being sequenced for the first time. The resulting phylogeny divided the Unionidae into 6 supported subfamilies and 18 tribes, three of which are here named for the first time (i.e., Chamberlainiini nomen novum, Cristariini nomen novum and Lanceolariini nomen novum). Molecular analyses were complemented by investigations of selected morphological, anatomical and behavioral characters used in traditional phylogenetic studies. No single morphological, anatomical or behavioral character was diagnostic at the subfamily level and few were useful at the tribe level. However, within subfamilies, many tribes can be recognized based on a subset of these characters. The geographical distribution of each of the subfamilies and tribes is also presented. The present study provides important advances in the systematics of these extraordinary taxa with implications for future ecological and conservation studies. (C) 2016 Elsevier Inc. All rights reserved., Portuguese Foundation for Science and Technology (FCT) Grant [SFRH/BPD/108445/2015]; Vietnam Academy of Science and Technology [IEBR.CBT.TS07/2015]; Central Michigan University Poyang Lake Research Investment Fund; Key Laboratory of Poyang Lake Wetland and Watershed Research Director's Open Fund of Jiangxi Normal University, Financial support was provided by: the Portuguese Foundation for Science and Technology (FCT) Grant to EF (SFRH/BPD/108445/2015); the Vietnam Academy of Science and Technology under grant number IEBR.CBT.TS07/2015 for the Vietnamese field research; the Central Michigan University Poyang Lake Research Investment Fund and the Key Laboratory of Poyang Lake Wetland and Watershed Research Director's Open Fund of Jiangxi Normal University for procurement of and analysis of some Chinese specimens. The authors wish to thank: Jamie Smith, Collection manager of Mollusks, North Carolina Museum of Natural Sciences, Raleigh, North Carolina, for all of her efforts to ship tissue samples to be used in this project; the Confederated Tribes of the Umatilla Indian Reservation for providing access to specimens of A. nuttalliana.

00000; International audience; Asari (= Manila) clam, Ruditapes philippinarum, is the second bivalve mollusc in terms of production in the world and, in many coastal areas, can beget important socio-economic issues. In Europe, this species was introduced after 1973. In Arcachon Bay, after a decade of aquaculture attempt, Asari clam rapidly constituted neo-naturalized population which is now fished. However, recent studies emphasized the decline of population and individual performances. In the framework of a national project (REPAMEP), some elements of fitness, stressors and responses in Arcachon bay were measured and compared to international data (41 publications, 9 countries). The condition index (CI=flesh weight/shell weight) was the lowest among all compared sites. Variation in average Chla concentration explained 30% of variation of CI among different areas. Among potential diseases, perkinsosis was particularly prevalent in Arcachon Bay, with high abundance, and Asari clams underwent Brown Muscle Disease, a pathology strictly restricted to this lagoon. Overall element contamination was relatively low, although arsenic, cobalt, nickel and chromium displayed higher values than in other ecosystems where Asari clam is exploited. Finally, total hemocyte count (THC) of Asari clam in Arcachon Bay, related to the immune system activity, exhibited values that were also under what is generally observed elsewhere. In conclusion, this study, with all reserves due to heterogeneity of available data, suggest that the particularly low fitness of Asari clam in Arcachon Bay is due to poor trophic condition, high prevalence and intensity of a disease (perkinsosis), moderate inorganic contamination, and poor efficiency of the immune system.

The aim of the present study was to identify environmental factors that could explain the distribution of different pathologies of commercially exploited intertidal bivalves in an Atlantic lagoon, Arcachon Bay. In particular, the role of the salinity gradient as a driver was explored. The Manila clam Ruditapes philippinarum experienced two severe pathologies, perkinsosis, which is due to a protozoan parasite, and brown muscle disease (BMD), the etiological agent of which remains unknown. Perkinsus olseni infection was very low in a small low-salinity area but, at the scale of the entire lagoon, was more influenced by organic matter content in the sediment and by emersion time. BMD prevalence was also 2.6 times higher in the higher organic content area but was also negatively correlated with salinity. The sympatric cockle (Cerastoderma edule) was affected by eight trematode species. These parasites have a complex life cycle that generally involves three free-living host species. The distribution of the different trematode communities was rather patchy within Arcachon Bay with no clear relationship with measured environmental factors. The dominance of particular trematode species could be due to the presence of other hosts involved in their life cycle, making it more difficult to detect a major environmental driver. This survey demonstrated that salinity is not a major factor explaining disease distribution in this temperate lagoon. This result has consequences for the research of 'refuge areas' (free of diseases) or 'hot spots' (heavy infection) for species of high economic value.

Le, Van Tu Do Van Tho, Phan, Doan Dang (2015): Binhthuanomon vinhtan, a new genus and new species of semi-terrestrial freshwater crab (Crustacea: Decapoda: Brachyura: Potamidae) from south central Vietnam. Zootaxa 4052 (1): 117-126, DOI: http://dx.doi.org/10.11646/zootaxa.4052.1.6

Binhthuanomon vinhtan sp. nov. (Figs. 2 ���4, 6) Material examined. Holotype: male (53.9 �� 42.9 mm) (ITB-FC PNx01), 11 �� 22 ' 50.5 "N 108 �� 47 '49.0"E, Nui Chua, Vinh Tan commune, Tuy Phong district, Binh Thuan Province, Vietnam, 700 m, coll. Phan Doan Dang & Le Van Tho, July 2014. Paratypes: 6 male (51.3 40.0 mm, 50.5 �� 40.0 mm, 47.0 �� 37.0 mm, 46.0 �� 37.0 mm, 41.0 �� 32.0 mm, 35.0 �� 28.0 mm) (ITB-FC PNx02-07), 3 female (37.0 �� 29.5 mm, 34.3 25.7 mm, 23.8 18.8 mm) (ITB-FC PNx08- 10), same data as holotype. Comparative material. Villopotamon thaii Dang & Ho, 2003: Holotype, male (54.5 �� 40.2 mm) (IEBR), stream at Ba Na (Quang Nam province), Vietnam, coll. unknown, 20 April 2002. Paratypes: 1 male (50.9 �� 38.2 mm), 2 females (larger 40.6 �� 35.6 mm) (IEBR), same data as holotype. Balssipotamon ungulatum (Dang & Ho, 2003): Holotype, male (57.9 �� 44.8 mm) (IEBR), stream at Ninh Hai (Ninh Phuoc District, Ninh Thuan Province), Vietnam, coll. unknown, 29 September 2002. Paratypes: 1 male (52.0 �� 39.4 mm), 1 female (55.0 �� 41.3 mm) (IEBR), same data as holotype. Laevimon kottelati Yeo and Ng, 2005: male (45.4 �� 31.9 mm) (IEBR-FC LKx01), 20 �� 46 ' 58.5 "N 107 ��0' 1.8 "E, unnamed small stream near Trung Trang cave, Ca Ba island, Hai Phong, Vietnam. Hainanpotamon rubrum (Dang & Tran, 1992): male (22.6 �� 16.8 mm) (IEBR-FC HRx01), Xuan Son National Park, Phu Tho, Vietnam. Description. Carapace distinctly transverse, about 1.26 times broader than long (n = 10), high; dorsal surface strongly inflated, swollen vertically, laterally, glabrous; regions poorly defined, cervical grooves undiscernible, Hshaped depression shallow but distinct (Figs. 2 A, 3 A). Epigastric cristae poorly developed, rounded, smooth, confluent with postorbital cristae; postorbital cristae poorly developed, straight, rounded, smooth; regions behind epigastric, postorbital cristae smooth (Figs. 2 A, 3 A). Frontal margin broadly emarginate medially; frontal region strongly deflected downward, smooth; antennular fossae slit-like when viewed from frontal view; orbital region very narrow, smooth; supraorbital margin very gently sinous, cristate; infraorbital margins cristate, almost straight; orbital region smooth, relatively narrow; eyes normally developed; subhepatic, subbranchial regions smooth (Figs. 2 A, B). External orbital angle low but distinct, triangular, smooth; epibranchial tooth indistinct, separated from external orbital angle by wide cleft; anterolateral margin convex, smooth; posterolateral margin rounded, not convergent posteriorly; branchial region smooth, inflated; metabranchial region almost smooth, with faint oblique striae (Figs. 2 A, B). Epistome anterior margin with median triangle; posterior margin with low median triangular tooth, slightly crenulated, with outer part slightly concave (Fig. 2 B). Third maxilliped glabrous; ischium rectangular, about 1.67 times longer than broad, with distinct longitudinal median sulcus; merus squarish, longer than half (0.54 times) of ischium length, with concave outer surface; palp normal with tip exceeding proximal margin of merus; exopod relatively long, exceeding upper edge of ischium, exceeding proximal margin of merus, distally tapered, blunt tooth on distal part of inner margin weakly developed, with short but distinct flagellum, slightly longer than half width (0.63) of merus (Figs. 2 B, 3 C). Ambulatory legs normal, glabrous, relatively slender; dactyli elongated, slender; merus unarmed with upper margin weakly serrated; in second pair dactylus about 6.56 times longer than proximal width, propodus about 2.71 times longer than broad, about 0.83 times length of dactylus, carpus about 0.76 times length of dactylus, merus about 1.41 times longer than dactylus (n = 4); fourth pair with dactylus about 6.19 times longer than proximal width, propodus about 0.88 times length of dactylus, carpus about 0.81 times length of dactylus, merus about 3.04 times longer than proximal width, about 1.34 times longer than dactylus (n = 4) (Fig. 2 A). Suture between anterior thoracic sternites 2, 3 complete, distinct, straight; groove between sternites 3, 4 distinct, broad, not fused with tip margin of abdominal cavity (Fig. 2 C); thoracic sternites 5, 6 medially interrupted; sternites 7, 8 medially separated by distinct longitudinal median suture. Male abdominal cavity reaching imaginary line joining middle points of cheliped bases (at sternite 4) (Fig. 2 D). Tubercles of male abdominal-locking mechanism positioned in thoracic sternite 5. Male abdomen broadly triangular; telson narrowly triangular, broader than long, lateral margins deeply concave, tip rounded, subequal in length to sixth segment; segment 6 with proximal width about 2.29 times length, lateral margins gently convex; lateral margins of segments 4 to 5 straight; lateral margins of segment 3 gently convex (Figs. 2 C, 3 B). Gl sinuous, distinctly sinuous (Fig. 2 D); terminal segment slender, tapered, about 0.26 times length of subterminal segment, about 2.82 times longer than proximal width, without dorsal flap, sparsely covered by pubescence in ventral side, groove for accommodation of G 2 marginal; subterminal segment relatively slender, sinuous, without neck-like distal part, subdistal cleft or shelf on outer margin (Figs. 4 A���H). G 2 equal or slightly longer than G 1 with distal segment shorter than half length of basal segment (Figs. 4 I���J). Etymology. The new species is named after the type locality, Vinh Tan. The name is used as a noun in apposition. Coloration. Carapace, abdomen and ambulatory legs reddish brown, chelipeds with magenta color. Ecological notes. This species inhabits forested mountain areas (Figs. 5 A���C). The crabs were found living in vertical burrows, beneath large rocks or under fallen trees, near one stream bank (Figs. 6 A, B). Few individuals wer also found in the stream, however. It is believed that this species spends almost all of their time in terrestrial environments. Indeed, the more terrestrial habit is usually associated with freshwater crabs with a high and swollen carapace (Yeo & Ng, 2005). The crabs are usually active in the evening until early morning. In the evening, the stream area is usually covered by fog and therefore very humid. It is very difficult to find the crabs in the dry season. The best time to collect them is during the rainy season, especially after heavy rain. The crabs feed primarily on insects and plants along streams. Remarks. This species is found only in limited numbers in and around one small stream, 800 m in length, located in south central Vietnam. It could not be found in other regions around this area (north central and Central Highlands of Vietnam) during our surveys. We believe this species has a small distribution area. The area of occupancy is not part of any protected area and is strongly impacted by deforestation. Local people sometime catch these crabs for food; however, it is only when they accidentally collect them. Therefore, this species should be considered endangered due to limited range and impacts of deforestation on the IUCN Red List Categories and Criteria (IUCN, 2001)., Published as part of Le, Van Tu Do Van Tho & Phan, Doan Dang, 2015, Binhthuanomon vinhtan, a new genus and new species of semi-terrestrial freshwater crab (Crustacea: Decapoda: Brachyura: Potamidae) from south central Vietnam, pp. 117-126 in Zootaxa 4052 (1) on pages 118-126, DOI: 10.11646/zootaxa.4052.1.6, http://zenodo.org/record/237939, {"references":["Dang, N. T. & Ho, T. H. (2003) Two new potamid crab species of Potamidae from southern part of Vietnam. Journal of Biology, 25 (3), 7 - 13. [in Vietnamese].","Yeo, D. C. J. & Ng, P. K. L. (2005) On a new genus and species of freshwater crab from Vietnam, with comments on the nomenclatural status of Orientalia Dang, 1975 (Crustacea: Brachyura: Potamidae: Potamiscinae). Zootaxa, 917, 1 - 15."]}

Genus Binhthuanomon, n. gen. Type species. Binhthuanomon vinhtan, new species, by present designation Diagnosis. Carapace distinctly transverse, high, dorsal surface strongly convex transversely, longitudinally, surfaces conspicuously smooth, grooves weak to indistinct, regions poorly defined; epigastric, postorbital cristae not separated, indistinct, rounded, smooth; postorbital cristae close to supraorbital margins; postorbital regions narrow; frontal margin strongly deflexed downwards, appears narrow from dorsal view; anterolateral margin rounded, smooth; epibranchial tooth poorly developed, almost absent; external orbital angle low but distinct, triangular. Flagellum of exopod of third maxilliped short, tip blunt, slightly longer than half width of merus. Male abdomen broadly triangular. Male telson with lateral margins concave. G 1 sinuous; terminal segment slender, tapered, sinuous without dorsal fold, about 0.26 times length of subterminal segment. G 2 with distinct distal segment, shorter than half length of basal segment, basal segment with outer margins slightly convex. Etymology. The genus is named after the location, the province of Binh Thuan, in combination with the genus name Potamon. The gender is neuter. Remarks. The general carapace shape and G 1 of the new genus are superficially similar to Balssipotamon ungulatum (Dang & Ho, 2003), and Villopotamon thaii Dang & Ho, 2003. It can nevertheless be easily distinguished from these two species by the following characteristics: 1) carapace is high, much inflated and swollen (relatively flat carapace in Balssipotamon and Villopotamon); 2) H-shaped depression is shallow (Hshaped depression deep in the two genera); 3) epigastric and postorbital cristae are indistinct (epigastric and postorbital cristae distinct, sometimes sharp in the two genera); 4) postorbital cristae is close to supraorbital margins (postorbital cristae not close to supraorbital margins in the two genera); 5) postorbital regions are very narrow (postorbital regions slightly narrow or wide in the two genera); 6) anterolateral margin is rounded and smooth (anterolateral margin sharp and serrated in the two genera); 7) epibranchial tooth is poorly developed, almost absent (epibranchial tooth poorly developed but visible in the two genera); 8) external orbital angle is low (external orbital angle not low in the two genera); 9) groove between sternites 3 and 4 is deep (groove between sternites 3 and 4 shallow in the two genera); 10) lateral margins of telson are concave (lateral margins of telson almost straight in the two genera); and 11) G 1 is sinuous (strongly sinuous in Villopotamon or slightly sinuous in Balssipotamon), with terminal segment slender (terminal segment more slender, sinuous and elongated in Villopotamon or stout and short in Balssipotamon). Moreover, the new genus lives in semi-terrestrial habitats, whereas Villopotamon and Balssipotamon occupy freshwater habitats. Dang & Ho (2003) established a new genus, Villopotamon, for a new species, Villopotamon thaii Dang & Ho, 2003. Yeo & Ng (2007) subsequently included four more species in the genus, all formerly in Potamon sensu lato (Yeo & Ng, 1999; Dang & Ho, 2003), viz., V. frushstorferi (Balss, 1914), V. klossianum (Kemp, 1923), and V. ungulatum (Dang & Ho, 2003). Dang & Ho (2008) identified a new genus, Balssipotamon, and compared it with Villopotamon. The new genus Balssipotamon included two species, B. ungulatum (Dang & Ho, 2003), and B. fruhstorferi (Balss, 1914) (Dang & Ho, 2008, 2012). Recently more specimens collected from many localities of southern Vietnam showed a high similarity between these genera in terms of the morphology of the carapace and G 1 structures. Further studies are required to clarify the relationship between the two genera. Binhthuanomon is also superficially similar with Hainanpotamon Dai, 1995, and Laevimon Y eo & Ng, 2005, owing to its high, swollen, and smooth carapace, and the long, slender ambulatory dactyli. Binhthuanomon can nevertheless be distinguished from Hainanpotamon and Laevimon by the following characteristics: 1) suture between sternites 3 and 4 distinct, broad (not discernible in Hainanpotamon or by a distinct, strong ridge in Laevimon; and 2) G 1 terminal segment filiform, long, without proximal dorsal flap (terminal segment conical in Hainanpotamon or subcylindrical in Laevimon. with proximal dorsal flap)., Published as part of Le, Van Tu Do Van Tho & Phan, Doan Dang, 2015, Binhthuanomon vinhtan, a new genus and new species of semi-terrestrial freshwater crab (Crustacea: Decapoda: Brachyura: Potamidae) from south central Vietnam, pp. 117-126 in Zootaxa 4052 (1) on page 118, DOI: 10.11646/zootaxa.4052.1.6, http://zenodo.org/record/237939, {"references":["Dang, N. T. & Ho, T. H. (2003) Two new potamid crab species of Potamidae from southern part of Vietnam. Journal of Biology, 25 (3), 7 - 13. [in Vietnamese].","Yeo, D. C. J. & Ng, P. K. L. (2007) On the genus \" Potamon \" and allies in Indochina (Crustacea: Decapoda: Brachyura: Potamidae). The Raffles Bulletin of Zoology, Supplement No. 16, 273 - 308.","Yeo, D. C. J. & Ng, P. K. L. (1999) The state of freshwater crab taxonomy in Indochina (Decapoda, Brachyura). In: F. R. Schram & J. C. v. Vaupel Klein (Eds), Crustaceans and the biodiversity crisis. Proceedings of the Fourth International Crustacean Congress, Amsterdam, The Netherlands, July 20 - 24, 1998. Brill, Leiden, pp. 637 - 646.","Dang, N. T. & Ho, T. H. (2008) On the taxonomy of freshwater crabs allied to the genus Potamon (Potamidae) in Vietnam. Journal of Biology, 30 (2), 12 - 17."]}

A new genus and new species of semi-terrestrial crab of the family Potamidae, Binhthuanomon vinhtan n. sp., is described from south central Vietnam. The new genus is morphologically closest to Villopotamon DangHo, 2003, and Balssipotamon DangHo, 2008, in the shapes of the carapace and first gonopod but is easily distinguished by distinct carapace characteristics and gonopod 1 structures, and the habitat occupied.

Vietnam has the second highest diversity of freshwater mussels (Unionida) in Asia after China. The purpose of this paper is to compile an up-to-date list of the modern unionid fauna of Vietnam and its current conservation status. Unfortunately, there has been relatively little research on this fauna in Vietnam. Fifty-nine species of Unionida have been recorded from Vietnam based on literature, museum records, and our fieldwork. Fifty were assessed in the International Union for Conservation of Nature (IUCN) Red List 2016 in the IUCN categories of Critically Endangered (four species, 6.8%), Endangered (seven species, 12%), Vulnerable (one species, 1.7%), Near Threatened (two species, 3.4%), Least Concern (23 species, 39%), Data Deficient (11 species, 18.6%), and Not Evaluated (11 species, 18.6%). Considering the impacts of pollution, timbering, agriculture, and damming of rivers, research on the diversity and conservation status of freshwater mussels is very urgently needed to propose specific conservation measures for these species in Vietnam. If all taxa listed as Data Deficient are found to be threatened, with around 42% of species threatened, this fauna would be one of the most threatened freshwater molluscan faunas in Asia.

A new species of potamid freshwater crab, Tiwaripotamon vixuyenense sp. nov., is described from caves in Ha Giang, northern Vietnam. The new species can be distinguished from congeners by a suite of characters, including the relatively small epibranchial tooth, more slender ambulatory legs and a proportionately stout male first gonopod. Molecular data using the mitochondrial cytochrome oxidase subunit I (COI) supports its placement as a new species. The molecular data also supports the inclusion of another species, Geothelphusa vietnamica DangHo, 2002, from Ninh Binh, south of Hanoi, Vietnam in Tiwaripotamon Bott, 1970. The live coloration of T. vietnamicum and T. edostilus NgYeo, 2001 is provided to help field identification.

A new genus and new species of semi-terrestrial crab of the family Potamidae, Binhthuanomon vinhtan n. sp., is described from south central Vietnam. The new genus is morphologically closest to Villopotamon Dang & Ho, 2003, and Balssipotamon Dang & Ho, 2008, in the shapes of the carapace and first gonopod but is easily distinguished by distinct carapace characteristics and gonopod 1 structures, and the habitat occupied.

A new species of potamid freshwater crab, Tiwaripotamon vixuyenense sp. nov., is described from caves in Ha Giang, northern Vietnam. The new species can be distinguished from congeners by a suite of characters, including the relatively small epibranchial tooth, more slender ambulatory legs and a proportionately stout male first gonopod. Molecular data using the mitochondrial cytochrome oxidase subunit I (COI) supports its placement as a new species. The molecular data also supports the inclusion of another species, Geothelphusa vietnamica Dang & Ho, 2002, from Ninh Binh, south of Hanoi, Vietnam in Tiwaripotamon Bott, 1970. The live coloration of T. vietnamicum and T. edostilus Ng & Yeo, 2001 is provided to help field identification.