Revision of the guttata-group of Alona s. lato leads to its translocation to Prendalona Sousa, Elmoor-Loureiro & Santos, 2018 (Cladocera: Anomopoda: Chydoridae).

Revision of the guttata-group of Alona s. lato justifies its translocation to the genus Prendalona Sousa, Elmoor-Loureiro & Santos, 2018. Emended diagnosis of the genus and diagnoses for all its species are provided. Prendalona belong to the Hexalona-clade of Alona s. lato, it is a sister-group of genus Flavalona Sinev & Dumont, 2016, but differs from the latter in: (1) minute lateral head pores without any pockets below, (2) absence of the genital process on male postabdomen, and (3) absence of inner setae on endites 1-2 of thoracic limb I. Morphology of North American P. barbulata (Megard, 1967) and widely distributed P. guttata (Sars, 1862) is investigated in detail for the first time. Prendalona julietae sp. nov.,sibling-species of P. guttata, is described from Brazil. Global diversity and distribution patterns of Prendalona are discussed.

Anthalona vandammei sp. nov. from Thailand, a sibling species of Neotropical Anthalona brandorffi (Sinev & Holwedell, 2002) (Cladocera: Anomopoda: Chydoridae).

A new rare species of Anthalona Van Damme, Dumont & Sinev, 2011, Anthalona vandammei sp. nov. (Anomopoda: Chydoridae), is described from Thailand. It is a sister species of Neotropical Anthalona brandorffi (Sinev & Holwedell, 2002), sharing three important synapomorphies: (1) postabdomen widening distally in the anterior portion; (2) long posterior setae of valves, with the last setae located at the posteroventral angle of valves; and (3) only two flaming-torch setae of thoracic limbs IV. A. brandorffi and A. vandammei sp. nov. are similar habitually, but can be clearly distinguished by details of thoracic limb morphology. A. vandammei sp. nov. differs from A. brandorffi in (1) limb 1 IDL seta 3 with a basal spine much thicker and much longer than others, (2) longer setae e-f of endite 2 of limb I and (3) scraper 7 of limb II being only slightly smaller than scraper 6. The amphi-Pacific distribution of the brandorffi-clade of Anthalona is explained best by the Boreotropical hypothesis.

Spring and autumn fauna of Cladocera (Crustacea: Branchiopoda) in the center of East Asia plain: Hunan and Hubei Provinces of China.

Cladoceran (Crustacea: Branchiopoda) fauna of Hunan and Hubei provinces of China was studied in April 2014 and October 2018. 49 species of Cladocera were found, Anthalona sanoamuangae Sinev & Kotov, 2012 was recorded for China for the first time. Eight species were newly recorded for central China, taxonomic status of four species was clarified. Among the observed species, 19 taxa are predominantly Boreal, 13 species are recorded predominantly in south part of temperate zone and subtropics, and 17 species are mainly tropical. Significant difference was revealed between the spring and autumn fauna: Boreal species were the most frequent in spring, whereas subtropical and tropical species became more common in autumn. Species diversity and composition of the cladoceran fauna in the center of East Asia plain is discussed.

South-East Asian populations of Karualona cf. karua (King. 1853) (Crustacea: Cladocera: Chydoridae) belong to a separate species.

Study of populations of Karualona cf. karua (King, 1853) (rustacea: Cladocera) from South-East Asia and Sri Lanka revealed that they belong to an undescribed taxon. Karualona fatimae sp. nov. differs from the Australian K. karua s. str. by a very small basal spine of postabdominal claw and the presence of small denticle on the anterior margin of labral keel. The latter character is unique for the genus. Morphology, distribution and phylogenetic position of the new species are discussed. Our data suggest that the diversity of Karualona is underestimated in most tropical regions, with at least one more undescribed taxon present in South-East Asia and one more taxon in Australia. An updated key for genus Karualona Dumont & Silva-Briano, 2000 of the Eastern Hemisphere is provided.

A new species of Coronatella Dybowski amp; Grochowski, 1984 (Cladocera: Chydoridae) endemic to Jeju Island (Republic of Korea).

Recently particular attention of cladocerologists has focussed on a subtropical-southern temperate zone of the Far East of Eurasia comprising a center of water flea (Crustacea: Cladocera) endemism. Two endemic taxa were described previously from Jeju Island (Republic of Korea), but still the cladocerans of this island are poorly known. The aim of this communication is to describe a new species of Coronatella (Coronatella) Dybowski Grochowski, 1894 (Anomopoda: Chydoridae) and discuss diagnostic characters of this taxon with reference to their diagnostic value in other cladoceran groups. Surprisingly, all characters discriminating C. (C.) jejuana sp. nov. from closest C. (C.) rectangula (Sars, 1862) are from the set suggested for chydorid species delimitation by Nikolai Smirnov more than 50 years ago. Therefore, a search for diagnostic characters of a potentially new taxon could concentrate on just some potentially important structures. However, a program of detailed redescriptions of previously established taxa is necessary for an adequate description of new taxa which are congeners of the former, and such comprehensive work is still in its infancy.

A new species of honeycombed Chydorus Leach, 1816 (Cladocera: Anomopoda: Chydoridae) from tundra of North-East Russia.

A new cladoceran of the faviformis-group of the genus Chydorus Leach, 1816 (Cladocera: Chydoridae), characterized by a honeycomb-like sculpture of valves and head shield, is described from tundra lakes and ponds in North-East Russia. Morphology of the new species was studied using optical and scanning electron microscopy. Chydorus izvekovae sp. nov. differs from all other species of the faviformis-group in a narrow labral keel with elongated apex, and in a greater number of meshes on the valves and head shield. Other species of the faviformis-group in the Western Hemisphere are distributed in the tropical-subtropical zone, they also inhabit mostly shallow waters with well-developed macrophyte zone.

Redescription of two Australian cladocerans of the subfamily Aloninae Dybowski amp; Grochowski (Cladocera: Anomopoda: Chydoridae).

Morphology of two Australian water fleas, Alona rigidicaudis (Smirnov, 1971) and Coronatella (Coronatella) novaezealandiae (Sars, 1904) (Crustacea: Cladocera) was studied by optical and scanning electron microscopy. Morphology of the thoracic limbs was studied in detail. Previously unknown ephippial females and males are described for both species. Alona rigidicaudis is close in morphology to the simplex-group of the genus Anthalona Van Damme, Sinev Dumont, 2011, but lack the main distinctive feature of Anthalona, the presence of cosmaria of lateral head pores. Morphology of Coronatella (Coronatella) novaezealandiae (Sars, 1904) is typical of the genus. Affinities and taxonomic position of studied species are discussed.

Complete mitochondrial genome of Ovalona pulchella (Branchiopoda, Cladocera) as the first representative in the family Chydoridae: Gene rearrangements and phylogenetic analysis of Cladocera.

Chydoridae are phytophilic-benthic microcrustaceans that make up a significant proportion of species diversity and play an important role in the littoral zone of freshwater ecosystems worldwide. Here, we provide the complete mitochondrial genome of Ovalona pulchella (King, 1853), determined by next-generation sequencing. The entire mitochondrial genome is 15,362 bp in length; this is the first sequenced mitochondrial genome in the family Chydoridae. The base composition and codon usage were typical of Cladocera species. The mitochondrial gene arrangement (37 genes) was not consistent with that of other Branchiopoda. Both maximum likelihood and Bayesian analyses supported each suborder and family of Branchiopoda as monophyletic groups. The relationships among the families were as follows: [(Leptestheriidae + Limnadiidae) + (Sididae + (Bosminidae + (Chydoridae + Daphniidae)))] + Triopsidae. The newly sequenced O. pulchella was most closely related to the family Daphniidae. The complete mitochondrial genome of O. pulchella also provides valuable molecular information for further analysis of the phylogeny of the Chydoridae and the taxonomic status of the Branchiopoda.

Notes on morphology and ecology of an elusive water flea Rhynchotalona latens (Sarmaja-Korjonen, Hakojärvi & Korhola, 2000) (Crustacea: Cladocera).

Very rare North European water flea Rhynchotalona latens (Sarmaja-Korjonen, Hakojärvi & Korhola, 2000) (Crustacea: Cladocera), found mostly as remains during subfossil studies, was found in North Karelia, Russia. The species inhabits waterlogged Sphagnum mosses at lake margins, but is not present in littoral zones of the lakes. Morphology of thoracic limbs of R. latens was studied for the first time; SEM studies of the species were conducted for the first time. Our data suggests that R. latens is a specialized interstitial moss-dwelling species, only accidentally found in open water, which explains its rarity in samples taken by standard sampling methods. Presence of R. latens subfossil remains in sediments specifically indicate presence of Sphagnum at the lake coast, typical for acid oligotrophic or dystrophiс lakes.

New data on morphology and distribution of Alona werestschagini Sinev, 1999the only Arcto-Alpine species of Chydoridae (Cladocera: Anomopoda) known to date.

Detailed study of morphology of Alona werestschagini Sinev, 1999 (Crustacea: Cladocera) confirms its affinities with Alona guttata Sars, 1862. A. werestschagini is the only Arcto-Alpine species among the family Chydoridae, distributed along Arctic coast of Eurasia and in mountains of Central Asia, newer recorded in temperate lowlands of the continent. In our opinion, the species evolved in mountainous regions of Central Asia, while its spreading to Arctic regions took place in Pleistocene.

Longitudinal gradient in the Camptocercus lilljeborgi Schoedler, 1862 species group (Cladocera: Anomopoda: Chydoridae).

A detailed study of morphology of the rare phytophilous cladoceran Camptocercus lilljeborgi Schoedler, 1862 revealed that populations from Eastern Siberia and Far East of Russia belong to a new species. C. smirnovi sp. nov. differs from C. lilljeborgi in body shape, morphology of ventral margin of valves, morphology of postabdomen, and length of IDL seta 1 of the thoracic limb I. C. lilljeborgi s. str. is distributed in Europe and Western Siberia, therefore, the lilljeborgi-group provides an example of the western-eastern differentiation in Northern Eurasia. Some characters of taxa from the lilljeborgi-group are convergently similar to the characters of the species of genus Graptoleberis Sars, 1862; both groups are adapted to a snail-like crawling on the surface of water macrophytes.

A new species of scavenger Cladocera Pseudochydorus Fryer, 1968 (Cladocera: Anomopoda: Chydoridae) from the Central Mexican Plateau.

A new species of the genus Pseudochydorus Fryer, 1968 is described from Central Mexico. P. margaritalfonsorum sp. nov. differs from the Old World species of the genus, P. globosus (Baird, 1843) and P. bopingi Sinev, Garibian Gu, 2016 in the morphology of thoracic limbs IIII. Analysis of existing literature data on distribution and morphology of Pseudochydorus in America suggest than P. margaritalfonsorum sp. nov. is an endemic of Central Mexican Plateau, and at least two more species of the genus are present in other regions of America.

A new species of Karualona Dumont amp; Silva-Briano, 2000 (Cladocera: Anomopoda: Chydoridae: Aloninae) from Northeast Thailand.

A new species of Aloninae, Karualona arcana sp. nov. (Cladocera: Chydoridae) is described from Northeast Thailand. It differs from other species of the genus Karualona Dumont Silva-Briano, 2000 by: (1) the inner distal lobe of limb I bearing two setae; (2) shape of the postabdomen; (3) setae on the apical segment of the antenna endopodite of equal thickness; and (4) the presence of setules on the anterior margin of labrum. Some morphological characteristics of this taxon do not match well with the genus diagnosis, but share several important characteristics as well, such as: (1) presence of two main head pores and minute lateral pores; (2) presence of a lateral indentation on labral plate; (3) presence of denticles on the posteroventral angle of valves; (4) two flaming-torch setae on endite of limb IV; and (5) lack of composite denticles on postabdomen.

Males and ephippial females of Oriental Chydoridae (Cladocera: Anomopoda) from Cat Tien National Park, South Vietnam.

Cladocera (Crustacea: Branchiopoda) of South-East Asia have been intensively investigated over the last decades, but males and ephippial females of many taxa remain unknown or poorly studied. Males and ephippial females of ten species of Chydoridae were collected by monthly sampling of eight water bodies during autumn-winter dry season in Сat Tien National Park, South Vietnam. Morphology of studied specimens is described and taxonomic status of studied species is discussed. Gamogenetic specimens were sparse in all studied taxa, contributing less than 8 % of the populations in samples. Gamogenetic specimens were found mostly during December-January, what suggests that daylight period is the main factor inducing a sexual reproduction in most studied species.

A new species of Flavalona Sinev amp; Dumont, 2016 (Crustacea: Branchiopoda) from Bale Mountains, Ethiopia.

Here we describe a new species of Flavalona Sinev Dumont, 2016 (Cladocera: Chydoridae) based on material from Bale Mountains, Ethiopia. F. darkovi sp. nov. clearly differs from other species of Flavalona known to date by fine ornamentation of valves, proportions of head pores, proximal exopod spine and seta on the middle exopod segment of antenna II. This species may be considered as endemic taxon of high mountain water bodies of Bale Mountains at an altitude of about 4000 m.a.s.l. Investigated species of the genus Flavalona in Africa demonstrate strong local mountain endemism accompanied by morphological differences between closest taxa, but the real diversity of this group in Africa is underestimated yet, and further studies are urgently need. Since the high mountain water ecosystems in Africa are especially vulnerable to increasing anthropogenic impact and global climate warming, it is necessary to speed up the studies of high mountain invertebrates and develop special measures for protection of such ecosystems.

Re-evaluation of the genus Biapertura Smirnov, 1971 (Cladocera: Anomopoda: Chydoridae).

The genus Biapertura Smirnov, 1971, with type species B. affinis (= Lynceus affinis Leydig, 1860) is re-evaluated, removing the affinis-group from polyphyletic Alona s. lato. Biapertura s. str. is a taxon which could be defined by large size (up to 1.1 mm), having head shield with triangular posterior portion and two connected major head pores, and by having massive postabdomen with over 10 well-developed composite marginal denticles and well-developed lateral fascicles of setulae. Thoracic limbs of Biapertura are of Hexalona-type, inner distal lobe of limb I bear extremely large, usually claw-like seta 1. Australian species of the genus, B. kendallensis (Henry, 1919) and B. elliptica (Sinev, 1997), are fully redescribed here. Morphological analysis suggests that Biapertura s. str. is a sister-group to Alona s. str. A key to seven species of the genus is provided and a discussion of their geographic distribution and habitat type is given.

High diversity of Cladocera (Crustacea: Branchiopoda) in a Ramsar site Lake Kud-Thing, Northeast Thailand.

An intensive study of cladoceran diversity in Lake Kud-Thing, a Ramsar site of Bueng Kan Province, Thailand, was conducted. One hundred and twenty-five qualitative samples were collected from 15 localities during the period from June 2012 to November 2014. A total of 58 species belonging to 38 genera was recorded. Three species, Chydorus idrisi Sinev 2014, Karualona kwangsiensis (Chiang 1963) and Streblocerus cf. serricaudatus (Fisher 1849) are new records for Thailand. The most species rich family was Chydoridae (32 species, 55% of the encountered species in the lake) followed by Sididae (8 species, 14%) and Macrothricidae (8 species, 14%) while only a single species of Ilyocryptidae was observed. The most frequently encountered planktonic species were Ceriodaphnia cornuta Sars 1885, Bosmina cf. meridionalis Sars 1904 and Ephemeroporus barroisi (Richard 1894). A newly described chydorid, Anthalona spinifera Tiang-nga, Sinev Sanoamuang 2016, was also recorded from this lake. The number of cladocerans recorded in this study is remarkably higher than that of previous studies in other natural lakes (17-40 species) within Thailand. In addition to earlier records, the number of cladocerans of Lake Kud-Thing has been updated to 62 species, about two times higher than that of other lakes in this region. Thus, our results suggest that Lake Kud-Thing is one of the biodiversity hotspots for Cladocera of Southeast Asia.

A new North Eurasian species of the Alona affinis complex (Cladocera: Chydoridae).

Our analysis of Alona cf. affinis (Cladocera: Chydoridae) populations from European Russia, Siberia and Far East of Russia bearing denticles at the posteroventral corner, based on both their morphology and genetic study considering variability of mitochondrial COI and 16S and nuclear 18S genes, revealed that they belong to a separate taxon described here as Alona sibirica sp. nov. Previously populations with denticles at the posteroventral corner were recorded from Sweden, Finland, Ukraine, European Russia, Kyrgyzstan and Mongolia, but never reported outside the temperate regions of Eurasia, so A. sibirica sp. nov. is presumably the only species of the A. affinis group with denticles at the posteroventral corner of the valves. The primary distribution area of the new species is North-East Palaearctic, while Eastern Europe and Central Asia are the areas of the species penetration, where it is less common and frequently coexisting with A. affinis s. str.

Revision of the elegans-group of Alona s. lato and its status as a subgenus of Coronatella Dybowski amp; Grochowski, 1894 (Cladocera: Anomopoda: Chydoridae).

The taxonomic status of the elegans-group of Alona s. lato (Cladocera: Anomopoda: Chydoridae) is herein examined. The West Palearctic Alona elegans Kurz, 1875 and poorly known African taxon Coronatella cf. bukobensis (Weltner, 1897) are redescribed, and new data on morphology of Coronatella circumfimbriata (Megard, 1967) and Coronatella rectangula (Sars, 1861) is added. Based on analysis of original and literature data, the elegans-group is herein suggested as a separate subgenus within the genus Coronatella, namely Coronatella (Ephemeralona) subgen. nov. Main diagnostic features of the latter include: (1) seta arising from the basal segment of antenna endopodite much longer than endopodite; (2) acessory seta of limb I long, almost as long as ODL seta; (3) setae 2-3 of IDL armed with uniform thin setulae; (4) exopodite of limb II with a very short, rudimentary seta. Coronatella (Ephemeralona) subgen. nov. is a morphologically uniform basal group of the genus. It is distributed mostly in the arid belt of the Old World, with a single species known from South Africa. C. (Coronatella) is distributed worldwide; it is composed of several distinct species-groups with overlapping areas of distribution. A checklist of Coronatella species is provided.

New species of Alpinalona Alonso amp; Sinev, 2017 (Cladocera: Anomopoda: Chydoridae) from South-East USA.

A new species of genus Alpinalona Alonso Sinev, 2017 is described from South-East USA. Alpinalona fornshelli sp. nov. differs from other species of the genus in: (1) over 35 setulae on posteroventral angle of the valves, organized into 5-6 groups; (2) a long basal spine of female postabdominal claw (about 0.3 claw length); and (3) thick long distalmost spines in basal pecten of postabdominal claw. Taxonomic position and distribution of the new species are discussed.