Dmitry A. Sidorov

Molecular taxonomy and phylogenetic affinities of two groundwater amphipods, Crangonyx islandicus and Crymostygius thingvallensis, endemic to Iceland.

The amphipod superfamily Crangonyctoidea is distributed exclusively in freshwater habitats worldwide and is characteristic of subterranean habitats. Two members of the family, Crangonyx islandicus and Crymostygius thingvallensis, are endemic to Iceland and were recently discovered in groundwater underneath lava fields. Crangonyx islandicus belongs to a well-known genus with representatives both in North America and in Eurasia. Crymostygius thingvallensis defines a new family, Crymostygidae. Considering the incongruences observed recently between molecular and morphological taxonomy within subterranean species, we aim to assess the taxonomical status of the two species using molecular data. Additionally, the study contributes to the phylogenetic relationships among several crangonyctoidean species and specifically among species from four genera of the family Crangonyctidae. Given the available data we consider how the two Icelandic species could have colonized Iceland, by comparing geographical origin of the species with the phylogeny. Regions of two nuclear (18S and 28S rRNA) and two mitochondrial genes (16S rRNA and COI) for 20 different species of three families of the Crangonyctoidea were sequenced. Four different methods were used to align the RNA gene sequences and phylogenetic trees were constructed using bayesian and maximum likelihood analysis. The Crangonyctidae monophyly is supported. Crangonyx islandicus appeared more closely related to species from the Nearctic region. Crymostygius thingvallensis is clearly divergent from the other species of Crangonyctoidea. Crangonyx and Synurella genera are clearly polyphyletic and showed a geographical association, being split into a Nearctic and a Palearctic group. This research confirms that the studied species of Crangonyctidae share a common ancestor, which was probably widespread in the Northern hemisphere well before the break up of Laurasia. The Icelandic species are of particular interest since Iceland emerged after the separation of Eurasia and North America, is geographically isolated and has repeatedly been covered by glaciers during the Ice Age. The close relation between Crangonyx islandicus and North American species supports the hypothesis of the Trans-Atlantic land bridge between Greenland and Iceland which might have persisted until 6 million years ago. The status of the family Crymostygidae is supported, whereas Crangonyx islandicus might represent a new genus. As commonly observed in subterranean animals, molecular and morphological taxonomy led to different conclusions, probably due to convergent evolution of morphological traits. Our molecular analysis suggests that the family Crangonyctidae needs taxonomic revisions.

Procrangonyx stygoedincus , a new species of subterranean amphipod (Pseudocrangonyctidae) from the Far East of Russia, with remarks on biogeographic relationships

Procrangonyx stygoedincus n. sp. (Amphipoda, Pseudocrangonyctidae) is described from subterranean fresh waters of the Edinka River basin, Primory territory, Russia. The affinity of the new species to its congeners is discussed, emphasizing morphological and biogeographical relationships. Procrangonyx stygoedincus n. sp., Amphipoda, Pseudocrangonyctidae est decrit des eaux douces souterraines du bassin du fleuve Edinka, territoire de Primory, Russie. Les affinites entre cette nouvelle espece et ses congeneres sont discutees en insistant sur les relations morphologiques et bio-geographiques.

Preliminary Analysis of Phylogenetic Relationships of the Asian-Pacific Endemial Subterranean Amphipod Genus Pseudocrangonyx Among Families and Genera of Crangonyctoidean Amphipods Inferred by Partial LSU rDNA Gene Sequences

To analyze the phylogenetic relationships of the genus Pseudocrangonyx within the superfamily Crangonyctoidea, we sequenced a partial LSU rDNA gene from four species (six specimens). The monophyly of Pseudocrangonyx and its affinity to Crymostygius were strongly supported by four reconstruction methods: neighbor-joining, minimum evolution, maximum-likelihood, and Bayesian inference. Current geographical distributions of the taxa studied and their phylogenetic relationships established in our study suggest that members of Pseudocrangonyctidae and Crymostygius diverged from a common Crangonyx-like ancestor in the Arctic Basin region of the northern hemisphere.

The spring-dwelling amphipod genus Lyurella (Peracarida, Amphipoda): systematics, distribution, and affinity, with description of the second representative from the Black Sea coast region

The hitherto monotypic, crangonyctid genus Lyurella Derzhavin, 1939, despite belonging to one of the most diverse and widely distributed amphipod families in the fresh waters of the Holarctic, is poorly studied due to its rarity and its limited distribution in the Caucasian region. Until now, it has been solely represented by its type species, Lyurella hyrcana Derzhavin, 1939 from the Lankaran lowlands of Azerbaijan and from Lahidjan in northern Iran. In this paper, a new species, Lyurella shepsiensis, is described from a spring in the Shepsi River basin in the Tuapse District of Russia. This is the first representative of this genus from Russia. The new species is closely similar to L. hyrcana, differing mainly in the morphology of the gnathopods and pereopods. This latter species is also redescribed herein, based on new collections that extend its known geographic range.

AMUROCRANGONYX, A NEW GENUS OF SUBTERRANEAN AMPHIPOD (CRANGONYCTIDAE) FROM THE RUSSIAN FAR EAST, WITH A REDESCRIPTION OF THE POORLY KNOWN CRANGONYX ARSENJEVI AND COMMENTS ON BIOGEOGRAPHIC RELATIONSHIPS

Abstract Amurocrangonyx n. gen. is described on the basis of recently collected specimens of Crangonyx arsenjevi (Derzhavin, 1927), a very poorly known subterranean amphipod crustacean originally described from springs in the Khor River basin of the Ussury River drainage in the Russian Far East. The species is redescribed from specimens obtained from the type-locality, Orekhovy spring, and a neotype is designated. A careful examination of the newly acquired material, although closely similar morphologically to Crangonyx, suggests that it represents a new genus in Crangonyctidae. However, determination of the precise phylogeographic relationship of Amurocrangonyx to Crangonyx or to other crangonyctoid genera in East Asia is unclear and must await molecular analyses.

Three new remarkable amphipod species (Crustacea: Gammaridae) from springs and subterranean waters of Central Asia

Three new species of the family Gammaridae-Gammarus troglomorphus, sp. n., G. parvioculatus, sp. n. from Lebap Province of Turkmenistan and Tadzocrangonyx alaicus, sp. n. from Batken Region of Kyrgyzstan are described and illustrated. Morphological studies of a closely related Turkmenistan population of G. cf. subaequalis-Garlyk, probably conspecific with Gammarus subaequalis Martynov, 1935 was provided. The affinity of new species to concerned taxa is discussed. To define phylogenetic position of mentioned species DNA barcode data are obtained. Gammarus troglomorphus and G. parvioculatus are close neighbors but exceedingly different morphologically. Gammarus troglomorphus is a troglobiont; G. parvioculatus is an eutroglophile, but with exception of slightly smaller eyes, not troglomorph. Both found only within small areas in the extreme East of Turkmenistan. Gammarus cf. subaequalis-Garlyk seems to extend from the same region far into the eastern Kyrgyzstan.

Zenkevitchiidae fam. nov. (Crustacea: Gammaroidea), with description of new subterranean amphipods from extremely deep cave habitats

ABSTRACT Previous phylogenetic analysis based on combined mitochondrial and nuclear gene sequences detected paraphyly of the Typhlogammaridae. To test this hypothesis a portion of large subunit (LSU-rDNA) gene sequences were obtained for typhlogammarid species from Caucasus. The Bayesian approach to LSU-rDNA sequences provided evidence for an independent origin of the Dinaric and Caucasus ‘typhlogammarid’ clades. A new family, Zenkevitchiidae fam. nov., is proposed to reconcile the observed phylogeny with the concept of monophyly. Using light microscopy, two mouthpart morphotypes of the Zenkevitchiidae fam. nov. species with quite different setae are identified. Taking into account these two morphotypes, a new classification is proposed – Adaugammarus revazi comb. nov., and Adaugammarus sandroruffoi comb. nov. Additionally, two new stygobiont zenkevitchiid amphipod species – Adaugammarus kasiani sp. nov. and Kruberia relicta sp. nov. – are described from Krubera Cave in Abkhazia. A distribution map and an identification key for the Zenkevitchiidae fam. nov. species of Transcaucasia are provided. http://zoobank.org/urn:lsid:zoobank.org:pub:90177B0C-BED0-4601-8CFC-3F774B22065C

A reassessment of the phylogenetic utility of genus-level morphological characters in the family Bogidiellidae (Crustacea, Amphipoda), with description of a new species of Eobogidiella Karaman, 1981

Abstract Bogidiellidae is the most diverse and cosmopolitan family of stygobiotic amphipods, and inhabits a variety of subterranean biotopes, especially interstitial habitats. While the family is characterized by considerable sexual dimorphism, this dimorphism has adversely affected our understanding of the systematics of the group. Most species have restricted geographic ranges and occur in difficult to sample habitats, so it is common for individual species descriptions to be based on a single sex. In this work we revisit an analysis of morphological characters in an attempt to clarify their phylogenetic utility in resolving taxonomic relationships among genera by introducing a new species, two additional characters, and phylogenetic statistical support values. Eobogidiella venkataramani sp. n., from a spring fed brook in the Shirawati River basin along the escarpment of the Western Ghats (Karnataka, India) differs from the only known congener, Eobogidiella purmamarcensis, from Argentina, in the structure of mouthparts, the shape and ornamentation on gnathopods and characters of the telson. Our phylogenetic analyses indicate that the available morphological characters are not sufficient to resolve phylogenetic relationships within Bogidiellidae, thus these characters alone cannot be used to determine the phylogenetic placement of Eobogidiella venkataramani sp. n. within the family. Nevertheless, Eobogidiella venkataramani sp. n. shares diagnostic characters with Eobogidiella, supporting placement of the new species in this genus. Our findings point towards a critical need to resolve relationships within the family using molecular approaches, along with the development of a suite of additional morphological characters for Bogidiellidae. This is the third species of Bogidiellidae from southern India.