Nataliya Budaeva

Larval development of Mooreonuphis stigmatis (Treadwell, 1922) (Polychaeta: Onuphidae) from the north-east Pacific

Abstract Development of Mooreonuphis stigmatis, one of the dominant polychaete species in the intertidal soft-bottom community in False Bay (San Juan Island, Washington, USA) has been studied from the 5-chaetiger stage to adult utilizing SEM techniques. Clearly lecithotrophic larvae develop inside the parental tubes until at least the 17-chaetiger stage. The earliest observed stage demonstrated reduced trochal ciliation. Description of development of various ciliated sensory organs is provided. Development of prostomial and peristomial appendages is similar to that found in other onuphid larvae. The chaetal progression pattern of larvae is described in detail and a unified terminology for larval and adult chaetae is suggested. Three major chaetal progression patterns in onuphids can be recognized. The phylogenetic status of some character states such as pseudocompound falciger dentition, origin of branchiae and subacicular hooks is discussed.

Benthic polychaetes from the northern Mid-Atlantic Ridge between the Azores and the Reykjanes Ridge

Abstract The polychaete macrofauna of the northern Mid-Atlantic Ridge between the Azores (42°N) and the southern tip of the Reykjanes Ridge (54°N) was studied based on the material obtained during the R/V G.O. Sars MAR-ECO cruise in 2004 and the two RRS James Cook ECOMAR cruises in 2007 and 2009. Polychaetes were collected from 28 trawl catches at depths from 981 to 3527 m. In total, 457 specimens were obtained and identified to 34 species-level taxa belonging to 18 families. Of the 34 species, 22 could be identified to known species (4 with reservation). Only 12 species were represented in more than 3 samples, and only 8 species were represented by more than 10 specimens. Lumbriclymenella nasuta comb. nov. is formally redescribed and the taxonomic status of Laetmonice britannica is raised from subspecies to species level. Several possibly undescribed species are present in the material, but lack of sufficient material prevents formal descriptions. Taxonomic remarks and figures are included for future reference.

When molecules support morphology: Phylogenetic reconstruction of the family Onuphidae (Eunicida, Annelida) based on 16S rDNA and 18S rDNA

Onuphid polychaetes are tubicolous marine worms commonly reported worldwide from intertidal areas to hadal depths. They often dominate in benthic communities and have economic importance in aquaculture and recreational fishing. Here we report the phylogeny of the family Onuphidae based on the combined analyses of nuclear (18S rDNA) and mitochondrial (16S rDNA) genes. Results of Bayesian and Maximum Likelihood analyses supported the monophyly of Onuphidae and its traditional subdivision into two monophyletic subfamilies: Onuphinae and Hyalinoeciinae. Ten of 22 recognized genera were monophyletic with strong node support; four more genera included in this study were either monotypic or represented by a single species. None of the genera appeared para- or polyphyletic and this indicates a strong congruence between the traditional morphology-based systematics of the family and the newly obtained molecular-based phylogenetic reconstructions. Intergeneric relationships within Hyalinoeciinae were not resolved. Two strongly supported monophyletic groups of genera were recovered within Onuphinae: ((Onuphis, Aponuphis), Diopatra, Paradiopatra) and (Hirsutonuphis, (Paxtonia, (Kinbergonuphis, Mooreonuphis))). A previously accepted hypothesis on the subdivision of Onuphinae into the Onuphis group of genera and the Diopatra group of genera was largely rejected.

Minibrachium, a new subgenus of Rhamphobrachium (Annelida: Onuphidae) from Australia with the description of three new species.

This study describes a new subgenus of miniature, progenetic Rhamphobrachium species from eastern Australia. Minibrachium, n. subg. is characterised by such paedomorphic features as lack of peristomial cirri and branchiae, possession of only two pairs of modified parapodia with spiny recurved hooks and very early onset of subacicular hooks. Three new species are described, of which at least R. (Minibrachium) nutrix n. sp., the type species (from Lizard Island, Great Barrier Reef), is a fully grown adult, brooding several 16- to 20-chaetiger juveniles in the parental tubes. Rhamphobrachium (M.) talboti n. sp. (from off Sydney) and R. (M.) fractum n. sp. (from Bass Strait), although twice as large as the type species, have only partially developed frontal lips, indicating either incomplete growth or presenting an additional paedomorphic character. We discuss the position of the new subgenus in the Rhamphobrachium complex and present a key to the subgenera of Rhamphobrachium and species of R. (Minibrachium).

Neosabellides lizae , a new species of Ampharetidae (Annelida) from Lizard Island, Great Barrier Reef, Australia

Neosabellides lizae, a new species of Ampharetidae, is described from the intertidal zone off Lizard Island, Great Barrier Reef, Queensland, Australia. The new species is referred to the genus Neosabellides based on the shape of the prostomium, three pairs of branchiae, 14 thoracic segments with notopodia, 12 thoracic uncinigerous segments, and the first two pairs of abdominal uncinigers of thoracic type. The new species differs from all known species of Neosabellides in having 14 abdominal uncinigerous segments.

Nothria nikitai, a new species of bristle worms (Annelida, Onuphidae) from the Gulf of Aden, Indian Ocean

A new species of Nothria is described from a subtidal locality in the Gulf of Aden. Nothria nikitai sp. n. represents the second species of the genus reported from the Indian Ocean, bringing the total number of Nothria species described to 20. The new species belongs to a group of species with the second pair of parapodia bearing pseudocompound falcigers only. It can be distinguished from its congeners by the early presence of branchiae (from chaetiger 6), which become very large and foliose in the middle part of the body. Presumably, such extreme development of branchiae has evolved as an adaptation to low oxygen conditions of the area. Ontogenetic variation in chaetal morphology and composition in the first three pairs of parapodia are described, allowing recognition of the smallest size of N. nikitai with the definitive set of characters.