The type specimens of bees (Hymenoptera: Apoidea) deposited in the Zoological Institute of the Russian Academy of Sciences, St. Petersburg. Contribution VI. Family Andrenidae, genus Andrena Fabricius, 1775, taxa described by V. Popov.

The type specimens for names of bee taxa in the genus Andrena Fabricius, 1775, described by V.B. Popov and which are deposited in the Zoological Institute, Russian Academy of Sciences (St. Petersburg) are reviewed. Primary types of 19 taxa are illustrated and detailed information is provided. New synonymies are established for Andrena chengtehensis Yasumatsu, 1935 (= A. nova Popov, 1940, syn. nov.) and A. skorikovi Popov, 1940 (=A. firuzaensis Popov, 1940, syn. nov.; =A. firuzaensis popovella Gusenleitner & Schwarz, 2002, syn. nov.; = Andrena iranella Popov, 1940, syn. nov.). Based on study of the the lectotype, we consider Andrena discophora transhissarica Popov, 1958, stat. rev., at the subspecific level, and not as a distinct species, as opposed to Shebl & Tadauchi (2011). Lectotypes are here designated for the following twelve nominal taxa: Andrena alashanica Popov, 1949, A. discophora transhissarica Popov, 1958, A. eoa Popov, 1949, A. fedtschenkoi djumensis Popov, 1947, A. firuzaensis Popov, 1940, A. iranella Popov, 1940, A. lebedevi Popov, 1940, A. nanshanica Popov, 1940, A. nova Popov, 1940, A. shakuensis Popov, 1949, A. subconsobrina Popov, 1949, and A. tadzhica Popov, 1949.

Trans-Japan Sea land-bridge disjunction: A case of vicariance in the subterranean genus Nipponasellus (Crustacea, Isopoda, Asellidae) in a large-scale biogeographical context.

This study examines nineteen phreatobiological hand pump samples collected in 20092010 in three separate areas of salmon river basins in the southern part of Primorye, in the Far East of Russia. For the first time, faunal groundwater patterns were assessed for the rivers of Eastern Manchuria, the Ussury River Basin and the rivers of the south-western slope of Sikhote Alin. A total of 164 species (including 32 stygobionts) belonging to the phyla Annelida, Mollusca and Arthropoda are first records of groundwater animals, and two of the stygobionts are described below as new species for Science. Nipponasellus sudzukhensis spec. nov. and N. matsumotoi spec. nov. are described and illustrated, and their taxonomic affinities with congeners are discussed. The morphology of male pleopod 2 of the genus Nipponasellus is re-examined using scanning electron microscopy (SEM), which revealed fine details of the pleopodal structures. The two new continental species of Nipponasellus were characterised by a distinct cannula completely immersed in ctenoid cuticular scales and the absence of a labial spur. Informal macrogroups were proposed based on the structure of the appendix masculina and an analysis of family distribution. The results of cladistic analyses revealed relationships between the proposed groups, but phylogenetic relationships within the Caecidotea-Proasellus group remain challenging. Common diagnostic characters of Nipponasellus showed that the group occupies an independent position close to the Caecidotea-Proasellus group rather than the Asellus-pattern sensu Magniez. Revised diagnosis for the genus Nipponasellus is given, including the two new species and the five previously described ones. The species diversity of East Asian stygobiotic asellid isopods is briefly reviewed to infer a biogeographic distribution pattern that emphasises the strict endemicity of members of the genus Nipponasellus. The intracontinental separation between continental Far East Asia and the Japanese archipelago highlights the biogeographic importance of the land-bridge in the Oligocene and raises questions about hypotheses explaining the (disjunct) distribution in East Asia, together with the circumstances preceding an ancient colonisation of the region.

The bees of the genus Andrena Fabricius, 1775 (Hymenoptera, Andrenidae) described by Ferdinand Morawitz from the collection of Aleksey Fedtschenko.

The type specimens of the genus Andrena Fabricius, 1775, described by Ferdinand Morawitz from the collection of Aleksey Fedtschenko deposited in the Zoological Museum of the Moscow State University and in the Zoological Institute, Russian Academy of Sciences, St. Petersburg (Russia), are critically reviewed. Precise information with illustrations of types for 52 taxa is provided; of these 39 species are valid and thirteen are invalid (ten synonyms and three homonyms). Lectotypes are here designated for the following 24 nominal taxa: Andrenaacutilabris Morawitz, 1876, A.aulica Morawitz, 1876, A.bicarinata Morawitz, 1876, A.combusta Morawitz, 1876, A.comparata Morawitz, 1876, A.corallina Morawitz, 1876, A.discophora Morawitz, 1876, A.fedtschenkoi Morawitz, 1876, A.initialis Morawitz, 1876, A.laeviventris Morawitz, 1876, A.leucorhina Morawitz, 1876, A.mucorea Morawitz, 1876, A.nitidicollis Morawitz, 1876, A.oralis Morawitz, 1876, A.planirostris Morawitz, 1876, A.ravicollis Morawitz, 1876, A.rufilabris Morawitz, 1876, A.sarta Morawitz, 1876, A.smaragdina Morawitz, 1876, A.sogdiana Morawitz, 1876, A.subaenescens Morawitz, 1876, A.tuberculiventris Morawitz, 1876, A.turkestanica Morawitz, 1876, and A.virescens Morawitz, 1876.

The type specimens of bees (Hymenoptera, Apoidea) deposited in the Zoological Institute of the Russian Academy of Sciences, St. Petersburg. Contribution V. Family Andrenidae, genus Andrena Fabricius, 1775, species described by E. Eversmann.

The type specimens for names of bee taxa in the genus Andrena Fabricius, 1775 described by E. Eversmann and which are deposited in the Zoological Institute, Russian Academy of Sciences (St. Petersburg) are reviewed. Primary types of 18 taxa are illustrated and detailed information is provided. New synonymy is established for three species: Andrena fallax Eversmann, 1852 (=A. ispida Warncke, 1965, syn. nov.); A. assimilis Radoszkowski, 1876 (=A. gravida Eversmann, 1852, nec A. gravida Imhoff, 1832, syn. nov.); A. nigriceps (Kirby, 1802) (=A. nigrifrons Eversmann, 1852, syn. nov.). Based on the lectotype studying we consider Andrena fulva Eversmann, 1852 (nec A. fulva Müller, 1766) to be a junior synonym of A. (Taeniandrena) eversmanniana Osytshnjuk, 1994, stat. rev., not A. (Margandrena) marginata Fabricius, 1776, as opposed to Gusenleitner & Schwarz (2002). Corrections on lectotype data are provided for four taxa: Andrena ambigua Eversmann, 1852, A. consobrina Eversmann, 1852, A. fulvitarsis Eversmann, 1852, and A. scita Eversmann, 1852.

Turcogammarus aralensis (Uljanin, 1875), a relict pontogammarid amphipod crustacean from the Aralo-Caspian paleobasin: redescription, phylogenetic position and biogeography.

The Ponto-Caspian region harbours the world's second most diverse lacustrine radiation of amphipod crustaceans. The taxonomic position of some of these species is unclear, due to incorrectly defined species limits, poor descriptions, and in some cases, poorly understood characters, such as armament of dorsal integuments. A pertinent example is Turcogammarus aralensis (Uljanin, 1875), which inhabits the Aral Sea and adjacent water bodies like the brackish lake Shalkar (Charkhal), lower reaches of the Syr Darya and Volga, and extends ca. 2500 km westwards in the Black Sea basin. This species has never been properly described, which has led to frequent taxonomic reshuffling. Herein, we provide a full re-description, ascertain its phylogenetic position using the cytochrome c oxidase subunit I (COI) marker, and review its geographical distribution. Our molecular analyses reveal T. aralensis as a sister species to the widespread Obesogammarus crassus (Sars, 1894), and its species status was further confirmed by three molecular species delimitation methods. Turcogammarus aralensis and O. crassus share many similarities such as the setation of the antennae and pereopods 3-4, and poorly setose posterior margin of pereopod 7 basis. Further study is needed to ascertain the validity of the genus Turcogammarus.

The type specimens of bees (Hymenoptera, Apoidea) deposited in the Zoological Institute of the Russian Academy of Sciences, St. Petersburg. Contribution IV. Family Andrenidae, genus Andrena Fabricius, 1775, species described by F. Morawitz.

The type specimens for names of bee taxa in the genus Andrena Fabricius, 1775 of family Andrenidae described by F. Morawitz and deposited in the Zoological Institute, Russian Academy of Sciences (St. Petersburg) are reviewed. Name-bearing types of 68 species are illustrated and detailed information is provided. Lectotypes are designated here for the following 32 nominal taxa: Andrena adjacens Morawitz, 1875, A. anthracina Morawitz, 1880, A. atrohirta Morawitz, 1893, A. croceiventris Morawitz, 1871, A. ehnbergi Morawitz, 1888, A. formosa Morawitz, 1877, A. glasunowi Morawitz, 1894, A. inconspicua Morawitz, 1871, A. laticeps Morawitz, 1877, A. melanura Morawitz, 1877, A. mongolica Morawitz, 1880, A. mucronata Morawitz, 1871, A. nigrobarbata Morawitz, 1871, A. nylanderi Morawitz, 1865, A. ochracea Morawitz, 1872, A. opaca Morawitz, 1868, A. orbitalis Morawitz, 1871, A. paliuri Morawitz, 1877, A. pretiosa Morawitz, 1893, A. ranunculorum Morawitz, 1877, A. rotundilabris Morawitz, 1877, A. sahlbergi Morawitz, 1888, A. salicina Morawitz, 1877, A. schencki Morawitz, 1866, A. semirubra Morawitz, 1875, A. sexguttata Morawitz, 1877, A. sylvatica Morawitz, 1877, A. transitoria Morawitz, 1871, A. truncatilabris Morawitz, 1877, A. tscheki Morawitz, 1872, A. virago Morawitz, 1894, A. curiosa Morawitz, 1877.

CEACAM5 overexpression is a reliable characteristic of CD133-positive colorectal cancer stem cells.

BACKGROUND: CD133 (prominin-1) is the most commonly used molecular marker of the cancer stem cells (CSCs) that maintain tumor progression and recurrence in colorectal cancer. However, the proteome of CSCs directly isolated from colorectal tumors based on CD133 expression has never been investigated. OBJECTIVE: To reveal biomarkers of CD133-positive colorectal CSCs. METHODS: Thirty colorectal tumor samples were collected from patients undergoing bowel resection. CD133-positive and CD133-negative cells were isolated by FACS. Comparative proteomic profiling was performed by LC-MS/MS analysis combined with label-free quantification. Verification of differentially expressed proteins was performed by flow cytometry or ELISA. CD133-knockout Caco-2 and HT-29 cell lines were generated using CRISPR-Cas9 gene editing. RESULTS: LC-MS/MS analysis identified 29 proteins with at least 2.5-fold higher expression in CD133-positive cells versus CD133-negative cells. Flow cytometry confirmed CEACAM5 overexpression in CD133-positive cells in all clinical samples analyzed. S100A8, S100A9, and DEFA1 were differentially expressed in only a proportion of the samples. CD133 knockout in the colon cancer cell lines Caco-2 and HT-29 did not affect the median level of CEACAM5 expression, but led to higher variance of the percentage of CEACAM5-positive cells. CONCLUSIONS: High CEACAM5 expression in colorectal cancer cells is firmly associated with the CD133-positive colorectal CSC phenotype, but it is unlikely that CD133 directly regulates CEACAM5 expression.

The CIMP-high phenotype is associated with energy metabolism alterations in colon adenocarcinoma.

BACKGROUND: CpG island methylator phenotype (CIMP) is found in 15-20% of malignant colorectal tumors and is characterized by strong CpG hypermethylation over the genome. The molecular mechanisms of this phenomenon are not still fully understood. The development of CIMP is followed by global gene expression alterations and metabolic changes. In particular, CIMP-low colon adenocarcinoma (COAD), predominantly corresponded to consensus molecular subtype 3 (CMS3, "Metabolic") subgroup according to COAD molecular classification, is associated with elevated expression of genes participating in metabolic pathways. METHODS: We performed bioinformatics analysis of RNA-Seq data from The Cancer Genome Atlas (TCGA) project for CIMP-high and non-CIMP COAD samples with DESeq2, clusterProfiler, and topGO R packages. Obtained results were validated on a set of fourteen COAD samples with matched morphologically normal tissues using quantitative PCR (qPCR). RESULTS: Upregulation of multiple genes involved in glycolysis and related processes (ENO2, PFKP, HK3, PKM, ENO1, HK2, PGAM1, GAPDH, ALDOA, GPI, TPI1, and HK1) was revealed in CIMP-high tumors compared to non-CIMP ones. Most remarkably, the expression of the PKLR gene, encoding for pyruvate kinase participating in gluconeogenesis, was decreased approximately 20-fold. Up to 8-fold decrease in the expression of OGDHL gene involved in tricarboxylic acid (TCA) cycle was observed in CIMP-high tumors. Using qPCR, we confirmed the increase (4-fold) in the ENO2 expression and decrease (2-fold) in the OGDHL mRNA level on a set of COAD samples. CONCLUSIONS: We demonstrated the association between CIMP-high status and the energy metabolism changes at the transcriptomic level in colorectal adenocarcinoma against the background of immune pathway activation. Differential methylation of at least nine CpG sites in OGDHL promoter region as well as decreased OGDHL mRNA level can potentially serve as an additional biomarker of the CIMP-high status in COAD.

Groundwater amphipods (Crustacea, Malacostraca) of India, with description of three new cavernicolous species.

Stygofaunistic surveys of peninsular India yielded, among others, three new cavernicolous amphipod taxa: Orientogidiella reducta gen. n., sp. n. in the Borra caves of Andhra Pradesh state, Bogidiella hindustanica sp. n. (Bogidiellidae) and Indoniphargus subterraneus sp. n. (Austroniphargidae) in the Kapiladevi caves of Telangana state. The new genus, Orientogidiella gen. n., is proposed to accommodate all the hitherto known species of the Bogidiella indica-group. This paper gives an illustrated description of the three new species together with their taxonomic affinities. A new record of O. indica comb. n., from the Guthikonda caves in Andhra Pradesh is provided as well. The structure of the Indoniphargus mandible is revisited with scanning electron microscopy (SEM) and revealed a poorly known flexible structure on the molar process which could be useful for phylogenetic purposes. The species diversity and geographic distribution of the Indian stygobiotic amphipods are briefly reviewed.

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.

HK3 overexpression associated with epithelial-mesenchymal transition in colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is a common cancer worldwide. The main cause of death in CRC includes tumor progression and metastasis. At molecular level, these processes may be triggered by epithelial-mesenchymal transition (EMT) and necessitates specific alterations in cell metabolism. Although several EMT-related metabolic changes have been described in CRC, the mechanism is still poorly understood. RESULTS: Using CrossHub software, we analyzed RNA-Seq expression profile data of CRC derived from The Cancer Genome Atlas (TCGA) project. Correlation analysis between the change in the expression of genes involved in glycolysis and EMT was performed. We obtained the set of genes with significant correlation coefficients, which included 21 EMT-related genes and a single glycolytic gene, HK3. The mRNA level of these genes was measured in 78 paired colorectal cancer samples by quantitative polymerase chain reaction (qPCR). Upregulation of HK3 and deregulation of 11 genes (COL1A1, TWIST1, NFATC1, GLIPR2, SFPR1, FLNA, GREM1, SFRP2, ZEB2, SPP1, and RARRES1) involved in EMT were found. The results of correlation study showed that the expression of HK3 demonstrated a strong correlation with 7 of the 21 examined genes (ZEB2, GREM1, TGFB3, TGFB1, SNAI2, TWIST1, and COL1A1) in CRC. CONCLUSIONS: Upregulation of HK3 is associated with EMT in CRC and may be a crucial metabolic adaptation for rapid proliferation, survival, and metastases of CRC cells.

Upregulation of NETO2 gene in colorectal cancer.

BACKGROUND: Neuropilin and tolloid-like 2 (NETO2) is a single-pass transmembrane protein that has been shown primarily implicated in neuron-specific processes. Upregulation of NETO2 gene was also detected in several cancer types. In colorectal cancer (CRC), it was associated with tumor progression, invasion, and metastasis, and seems to be involved in epithelial-mesenchymal transition (EMT). However, the mechanism of NETO2 action is still poorly understood. RESULTS: We have revealed significant increase in the expression of NETO2 gene and deregulation of eight EMT-related genes in CRC. Four of them were upregulated (TWIST1, SNAIL1, LEF1, and FOXA2); the mRNA levels of other genes (FOXA1, BMP2, BMP5, and SMAD7) were decreased. Expression of NETO2 gene was weakly correlated with that of genes involved in the EMT process. CONCLUSIONS: We found considerable NETO2 upregulation, but no significant correlation between the expression of NETO2 and EMT-related genes in CRC. Thus, NETO2 may be involved in CRC progression, but is not directly associated with EMT.

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.

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.

Differential expression of alternatively spliced transcripts related to energy metabolism in colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is one of the most common malignant tumors worldwide. CRC molecular pathogenesis is heterogeneous and may be followed by mutations in oncogenes and tumor suppressor genes, chromosomal and microsatellite instability, alternative splicing alterations, hypermethylation of CpG islands, oxidative stress, impairment of different signaling pathways and energy metabolism. In the present work, we have studied the alterations of alternative splicing patterns of genes related to energy metabolism in CRC. RESULTS: Using CrossHub software, we analyzed The Cancer Genome Atlas (TCGA) RNA-Seq datasets derived from colon tumor and matched normal tissues. The expression of 1014 alternative mRNA isoforms involved in cell energy metabolism was examined. We found 7 genes with differentially expressed alternative transcripts whereas overall expression of these genes was not significantly altered in CRC. A set of 8 differentially expressed transcripts of interest has been validated by qPCR. These eight isoforms encoded by OGDH, COL6A3, ICAM1, PHPT1, PPP2R5D, SLC29A1, and TRIB3 genes were up-regulated in colorectal tumors, and this is in concordance with the bioinformatics data. The alternative transcript NM_057167 of COL6A3 was also strongly up-regulated in breast, lung, prostate, and kidney tumors. Alternative transcript of SLC29A1 (NM_001078177) was up-regulated only in CRC samples, but not in the other tested tumor types. CONCLUSIONS: We identified tumor-specific expression of alternative spliced transcripts of seven genes involved in energy metabolism in CRC. Our results bring new knowledge on alternative splicing in colorectal cancer and suggest a set of mRNA isoforms that could be used for cancer diagnosis and development of treatment methods.

Effect of lentivirus-mediated shRNA inactivation of HK1, HK2, and HK3 genes in colorectal cancer and melanoma cells.

BACKGROUND: The switch from oxidative phosphorylation to glycolysis in proliferating cancer cells, even under aerobic conditions, has been shown first in 1926 by Otto Warburg. Today this phenomenon is known as the "Warburg effect" and recognized as a hallmark of cancer. The metabolic shift to glycolysis is associated with the alterations in signaling pathways involved in energy metabolism, including glucose uptake and fermentation, and regulation of mitochondrial functions. Hexokinases (HKs), which catalyze the first step of glycolysis, have been identified to play a role in tumorigenesis of human colorectal cancer (CRC) and melanoma. However, the mechanism of action of HKs in the promotion of tumor growth remains unclear. RESULTS: The purpose of the present study was to investigate the effect of silencing of hexokinase genes (HK1, HK2, and HK3) in colorectal cancer (HT-29, SW 480, HCT-15, RKO, and HCT 116) and melanoma (MDA-MB-435S and SK-MEL-28) cell lines using short hairpin RNA (shRNA) lentiviral vectors. shRNA lentiviral plasmid vectors pLSLP-HK1, pLSLP-HK2, and pLSLP-HK3 were constructed and then transfected separately or co-transfected into the cells. HK2 inactivation was associated with increased expression of HK1 in colorectal cancer cell lines pointing to the compensation effect. Simultaneous attenuation of HK1 and HK2 levels led to decreased cell viability. Co-transfection with shRNA vectors against HK1, HK2, and HK3 mRNAs resulted in a rapid cell death via apoptosis. CONCLUSIONS: We have demonstrated that simultaneous inactivation of HK1 and HK2 was sufficient to decrease proliferation and viability of melanoma and colorectal cancer cells. Our results suggest that HK1 and HK2 could be the key therapeutic targets for reducing aerobic glycolysis in examined cancers.

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.

Studies on subterranean amphipod crustaceans of Primory, Russia. Part 1. Three new species of the genus Pseudocrangonyx from springs and other groundwater habitats in far eastern Russia.

Three new species of the subterranean amphipod of the genus Pseudocrangonyx: P. tiunovi sp. nov., P. holsingeri sp. nov., P. sympatricus sp. nov. and male specimen for P. kseniae Sidorov, 2012 from the South Primory, Far East of Russia are described. The species were found in springs and related groundwater habitats of several river systems belonging to the Japan Sea basin. Phylogenetic analysis based on mt-cox1 sequences supported the species distinctness. A key for the South Primory species of Pseudocrangonyx is provided.

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.