Andrey A. Gontcharov

Ribosomal ITS Sequences Allow Resolution of Freshwater Sponge Phylogeny with Alignments Guided by Secondary Structure Prediction

Freshwater sponges include six extant families which belong to the suborder Spongillina (Porifera). The taxonomy of freshwater sponges is problematic and their phylogeny and evolution are not well understood. Sequences of the ribosomal internal transcribed spacers (ITS1 and ITS2) of 11 species from the family Lubomirskiidae, 13 species from the family Spongillidae, and 1 species from the family Potamolepidae were obtained to study the phylogenetic relationships between endemic and cosmopolitan freshwater sponges and the evolution of sponges in Lake Baikal. The present study is the first one where ITS1 sequences were successfully aligned using verified secondary structure models and, in combination with ITS2, used to infer relationships between the freshwater sponges. Phylogenetic trees inferred using maximum likelihood, neighbor-joining, and parsimony methods and Bayesian inference revealed that the endemic family Lubomirskiidae was monophyletic. Our results do not support the monophyly of Spongillidae because Lubomirskiidae formed a robust clade with E. muelleri, and Trochospongilla latouchiana formed a robust clade with the outgroup Echinospongilla brichardi (Potamolepidae). Within the cosmopolitan family Spongillidae the genera Radiospongilla and Eunapius were found to be monophyletic, while Ephydatiamuelleri was basal to the family Lubomirskiidae. The genetic distances between Lubomirskiidae species being much lower than those between Spongillidae species are indicative of their relatively recent radiation from a common ancestor. These results indicated that rDNA spacers sequences can be useful in the study of phylogenetic relationships of and the identification of species of freshwater sponges.

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.

Phylogenetic relationships among Orostachys subsection Orostachys species (Crassulaceae) based on nuclear and chloroplast DNA data

Nuclear ribosomal ITS and four cpDNA intergenic spacer sequences were used to assess how the patterns of molecular differentiation are related to taxonomic boundaries and geographic distribution in polymorphic and taxonomically complex Orostachys subsection Orostachys (Crassulaceae). Two major cpDNA lineages were identified in a set of Orostachys populations, lineage A, comprising 13 closely related haplotypes found in 11 populations of monocarpic O. malacophylla var. malacophylla, O. maximowiczii, and O. gorovoii and lineage B that included 9 out of 10 divergent haplotypes found in five populations of O. paradoxa, distinct in perennial stoloniferous habit. Our data suggest that the current concepts of O. malacophylla var. malacophylla, O. maximowiczii, and O. gorovoii are incompatible with the differentiation at the cpDNA level. Neither of these taxa could be allied to a particular haplotype or haplotype clade. The pattern of relationships between 7 ITS ribotypes found in 17 populations supported neither the morphology‐based taxonomic subdivision in the subsection Orostachys nor grouping according to geographical origin of the populations or lineages recovered with cpDNA data. A high level of similarity of ITS rDNA sequences between the subsection members suggests their relatively recent and rapid divergence from a common ancestor.

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