A new species of the Daphnia sinevi group (Crustacea: Cladocera: Daphniidae) from Sakhalin Island, Russian Far East

Daphnia curvirostris species complex is a cladoceran group (Crustacea: Cladocera) with maximum diversity in Eastern Palearctic. To date, several representatives of this complex are known from the Russian Far East. Here we describe a new species of the Daphnia sinevi species group from water bodies of Sakhalin Island. Morphology of its parthenogenetic females is similar to that in D. sinevi from the continental part of Asian Eurasia. However, we found diagnostic traits of D. sakhalinensis sp.nov. in morphology of the second pecten on postabdominal claw, armature of seta 2 on exopodite III, proportions of setae 1/ and 2 length on exopodite V, relative length of male rostrum and structure of the second pecten of male postabdominal claw. This work contributes to our full revision of the D. curvirostris species complex. Separation between continental and Sakhalin populations of D. sinevi group probably happened in Pliocene (about 5 MA) when Sakhalin began to separate from the mainland. However, we cannot exclude a version that populations of D. sakhalinensis sp.nov. appeared as a result of colonization of Sakhalin from the continent and further independent evolution of the island populations.

A new species group from the Daphnia curvirostris species complex (Cladocera: Anomopoda) from the eastern Palaearctic: taxonomy, phylogeny and phylogeography

The eastern Palaearctic is a centre of diversity for freshwater cladocerans (Crustacea), but little is known about the evolution and taxonomy of this diversity. Daphnia curvirostris is a Holarctic species complex that has most of its diversity in the eastern Palaearctic. We examined the phylogeography, rates of evolution and taxonomic status for each clade of the D. curvirostris complex using morphological and genetic evidence from four genes. The cybertaxonomical and morphological evidence supported an eastern Palaearctic clade, with at least four species (described here as the Daphnia korovchinskyi sp. nov. group) having diagnostic morphological characters. We also detected convergent morphological characters in the D. curvirostris complex that provided information about species boundaries. Two of the new species (Daphnia koreana sp. nov. and Daphnia ishidai sp. nov.) are known from single ponds and are threatened by human activity. Divergence time estimates suggested an ancient origin (12–28 Mya) for the D. korovchinskyi group, but these estimates are complicated by the small number of calibration points.

A new Central European species of the Daphnia curvirostris complex, Daphnia hrbaceki sp. nov. (Cladocera, Anomopoda, Daphniidae)

Although systematics of the cladoceran genus Daphnia (Cladocera: Daphniidae) has been intensively investigated for decades using both morphological and genetic approaches, new lineages are being discovered on all continents, including in well-studied regions. Among Holarctic daphnids, Daphnia curvirostris Eylmann, 1887 held an interesting position, sharing some morphological characters of both the D. pulex and D. longispina groups. Recently, additional species of the D. curvirostris complex have been discovered in the Eastern Palaearctic. Here, we describe a new species in this complex from Central Europe, D. hrbaceki sp. nov. It was discovered in small, newly created fishless pools in the Czech Republic, and an additional sample of apparently the same taxon was collected in 1951 in Slovakia. D. hrbaceki is the closest yet known relative of D. curvirostris, but remains genetically divergent from all members of the complex (based on the sequences of three mitochondrial genes: 12S, COI, and ND2). In general, adult females of this species are morphologically very similar to D. curvirostris. Unlike the latter species, D. hrbaceki may develop a specific hump-shaped dorsal outline of the carapace, presumably an inducible defence against invertebrate predators. Juveniles of the new species occasionally form neckteeth, which may also be retained in adult individuals. The species also shows substantial variation in the size of spines in the middle pecten of the postabdominal claw, similarly as in the Japanese member of the species complex, D. tanakai Ishida, Kotov & Taylor, 2006. This variable character of spine size in the postabdominal middle pecten (a transition from the pulex to the longispina group character), as well as a bent and heavily setulated terminal seta on the male 2nd endopodite (considered as the pulex group character), are typical for the new species. D. hrbaceki also differs from D. curvirostris as well as other members of the complex in the ephippial surface ultrastructure. Our study demonstrates the utility of such ultrastructural characters in Daphnia taxonomical studies.

An annotated checklist of the Algerian Cladocera (Crustacea: Branchiopoda)

We present an annotated checklist of the Cladocera (orders Ctenopoda and Anomopoda) from the continental waters of Algeria, based on published records and original data from analysis of samples from 112 water bodies collected in 2012-2016 in humid and semi-arid regions of the country. Thirty six species have been identified in this study. Three taxa (Daphnia obtusa, D. mediterranea and Ceriodaphnia cf. quadrangula, being an undetermined taxon belonging to the Ceriodaphnia genus) are new to Algeria and eight (Daphnia curvirostris, D. galeata, Macrothrix dadayi, Scapholeberis rammneri, Acroperus angustatus, Ovalona nuragica, O. orellanai and Coronatella anemae) are new to the Maghreb in general. The number of Cladoceran species recorded in Algeria has been raised to 81. More sampling efforts are needed to make this list more complete.

The taxonomic research of Jules Richard on Cladocera (Crustacea: Branchiopoda) and his collection at the National Museum of Natural History, USA

Jules Richard (1863-1945) contributed significantly to cladoceran taxonomy before he became Director of the Musee Oceanographique de Monaco and assistant to Prince Albert I-er de Monaco. His collection, including slides and samples preserved in ethanol, was purchased by E. A. Birge, subsequently incorporated into the collection of David G. Frey, and later gifted to the National Museum of Natural History, Smithsonian Institution. A list of publications of Richard about cladocerans is presented, as well a list of all new taxa described by him (three genera and 37 taxa of species rank), with information about type localities, synonymies and taxonomic comments. Lectotypes and in some cases paralectotypes are selected for Daphnia (Ctenodaphnia) bolivari Richard, 1888; D. (Daphnia) curvirostris insulana Moniez in Richard, 1896; Bosmina japonica Poppe & Richard, 1890; Grimaldina brazzai Richard, 1892 and Alona sarsi Richard, 1891. Syntypes exist for Alona moniezi Richard, 1888 and Pleuroxus letourneuxi (Richard, 1888). The ethanol samples of Richard that may contain species for which there are no types are discussed. In addition, samples in the collection of David G. Frey from type localities of Richard's species are noted. These samples could be important for future revisions of the Richard's taxa. A redescription of Pleuroxus letourneuxi (Chydoridae, Chydorinae) is given; Bosmina japonica Poppe & Richard, 1890 (Bosminidae), a junior synonym of B. longirostris (O. F. Muller, 1776), also is redescribed.