Occurrence and distribution of Pseudoscalibregma and Scalibregma (Annelida, Scalibregmatidae) in the deep Nordic Seas, with the description of Scalibregma hanseni n. sp.

Until recent years, only a few scalibregmatid species have been known from the Nordic Seas, largely from shelf and coastal waters. Access to a large collection from deep areas has made it possible to provide more knowledge on the diversity of this group in the area. Pseudoscalibregma parvum (Hansen, 1879) is here redescribed. The species has a wide geographic distribution in the Nordic Seas, the Barents Sea, and the Kara Sea. Type specimens of Eumenia longisetosa Théel, 1879 were found to be similar to specimens of P. parvum, confirming the synonymy of the species. A new species, Scalibregma hanseni n. sp., is described from specimens found on the continental slope. It is particularly characterised by having three pairs of rather simple branchiae. Both P. parvum and S. hanseni have small spines in the most anterior chaetiger(s), resembling spines reported from a few other Pseudoscalibregma and Scalibregma species and supporting the need to emend the genus diagnosis of Pseudoscalibregma. Scalibregma abyssorum Hansen, 1879 was reassessed and considered to be a nomen dubium. Scalibregma inflatum, which has a wide distribution along the Norwegian coast and continental shelf, is found to be restricted to depths above about 900 m. Depths from 600– 800 m on the continental slope represent a transition zone with fluctuations between temperate North Atlantic water (about 7°C) and cold Norwegian Sea water (below 0°C). The three species coexist in this zone, whereas P. parvum and S. hanseni n. sp. extend down to 1700 and 1200 m, respectively, on the slope at temperatures below 0°C

When standard DNA barcodes do not work for species identifcation: intermixed mitochondrial haplotypes in the Jaera albifrons complex(Crustacea: Isopoda)

Here, we characterise the standard “Folmer region” of the mitochondrial cytochrome c oxidase subunit 1 (CO1) marker and a fragment of nuclear 28S marker in four species of the Jaera albifrons complex. Jaera albifrons (Leach, 1814), Jaera ischiosetosa Forsman, 1949, Jaera praehirsuta Forsman, 1949, and Jaera forsmani Bocquet, 1950 were collected from localities on the Norwegian coast and identified with morphological characters. We compared DNA sequences with sequences available in GenBank and BOLDsystems and calculated haplotype networks and interspecific versus intraspecific genetic distances. These analyses revealed low interspecific genetic distance (CO1 0.00–1.57%, 28S 0.00–0.39%) and extensive haplotype sharing between J. albifrons group species and specimens from both sides of the North Atlantic for both CO1 and 28S. Genetic distances between J. albifrons group species and other Jaera species, however, exceeded 29% for both CO1 and 28S, with no haplotype sharing. These assessments, together with taxonomically unconstrained analyses with software ABGD and ASAP, show that these markers are unable to distinguish between the J. albifrons group of morphospecies. The sequences do, however, clearly identify J. albifrons species complex from other Jaera species. Thus, a likely hypothesis is that taxa in this complex represent a single species. Our results corroborate previous finds where discordance between mitochondrial gene clusters, AFLP, and other data highlights the potential conflict between different “species criteria” and the well-established distinction between gene trees and species trees. In operational terms, common protocols for metabarcoding will potentially underestimate sympatric species diversity with cases like the J. albifrons complex, if the members of this complex indeed represent different species.publishedVersio

Benthic invertebrates in Svalbard fjords—when metabarcoding does not outperform traditional biodiversity assessment

To protect and restore ecosystems and biodiversity is one of the 10 challenges identified by the United Nations’s Decade of the Ocean Science. In this study we used eDNA from sediments collected in two fjords of the Svalbard archipelago and compared the taxonomic composition with traditional methods through metabarcoding, targeting mitochondrial CO1, to survey benthos. Clustering of 21.6 mill sequence reads with a d value of 13 in swarm, returned about 25 K OTU reads. An identification search with the BOLD database returned 12,000 taxonomy annotated sequences spanning a similarity range of 50% to 100%. Using an acceptance filter of minimum 90% similarity to the CO1 reference sequence, we found that 74% of the ca 100 taxon identified sequence reads were Polychaeta and 22% Nematoda. Relatively few other benthic invertebrate species were detected. Many of the identified sequence reads were extra-organismal DNA from terrestrial, planktonic, and photic zone sources. For the species rich Polychaeta, we found that, on average, only 20.6% of the species identified from morphology were also detected with DNA. This discrepancy was not due to missing reference sequences in the search database, because 90–100% (mean 96.7%) of the visually identified species at each station were represented with barcodes in Boldsystems. The volume of DNA samples is small compared with the volume searched in visual sorting, and the replicate DNA-samples in sum covered only about 2% of the surface area of a grab. This may considerably reduce the detection rate of species that are not uniformly distributed in the sediments. Along with PCR amplification bias and primer mismatch, this may be an important reason for the limited congruence of species identified with the two approaches. However, metabarcoding also identified 69 additional species that are usually overlooked in visual sample sorting, demonstrating how metabarcoding can complement traditional methodology by detecting additional, less conspicuous groups of organisms.publishedVersio

Polychaetes from Jan Mayen (Annelida, Polychaeta)

A thorough literature review has been undertaken to establish the first complete account of polychaetes recorded from the area around the volcanic island of Jan Mayen. The annotated checklist lists 121 species-level taxa, representing an increase from the 75 species previously recorded. The checklist is based on existing records, supplemented with material sampled in 1999, from which 42 species new to the area were reported. Some previously reported species from the area have been excluded because of inadequate documentation. The polychaete fauna of Jan Mayen is comparable with that of the mainland Norwegian coast and the Svalbard area. No taxa unique to the island were found. However, knowledge of the marine invertebrate fauna in general at Jan Mayen is sparse because few surveys have been undertaken there. It is expected that future expeditions will reveal further new taxon records for the area.publishedVersio

Diversity of Orbiniella (Orbiniidae, Annelida) in the North Atlantic and the Arctic

In this work, the diversity of the genus Orbiniella in the Nordic Seas and the North Atlantic waters south of Iceland is studied based on the analyses of molecular markers (mitochondrial COI, 16S rDNA and nuclear ITS2) and morphological characters. Our results showed the presence of at least five genetic lineages in the studied material which could also be morphologically identified by their segmental annulation patterns, the number and the shape of acicular spines, and the length and the shape of pygidial lobes. The species name Orbiniella petersenae is assigned to one of the lineages restricting its geographical and vertical distribution to the deep-sea areas north of Iceland and Jan Mayen, and three lineages are described as new species (i.e., Orbiniella griegi Meca & Budaeva, sp. nov., Orbiniella mayhemi Meca & Budaeva, sp. nov., and Orbiniella parapari Meca & Budaeva, sp. nov.) elevating the number of known species in the genus to 25. Three deep-sea species of Orbiniella in our study are reported only north of the Greenland-Iceland-Scotland Ridge, one deep-sea species found south of the ridge. A single shallow-water species is distributed along the ridge and on the Norwegian shelf

Adding pieces to the puzzle: insights into diversity and distribution patterns of Cumacea (Crustacea: Peracarida) from the deep North Atlantic to the Arctic Ocean

The Nordic Seas have one of the highest water-mass diversities in the world, yet large knowledge gaps exist in biodiversity structure and biogeographical distribution patterns of the deep macrobenthic fauna. This study focuses on the marine bottom-dwelling peracarid crustacean taxon Cumacea from northern waters, using a combined approach of morphological and molecular techniques to present one of the first insights into genetic variability of this taxon. In total, 947 specimens were assigned to 77 morphologically differing species, representing all seven known families from the North Atlantic. A total of 131 specimens were studied genetically (16S rRNA) and divided into 53 putative species by species delimitation methods (GMYC and ABGD). In most cases, morphological and molecular-genetic delimitation was fully congruent, highlighting the overall success and high quality of both approaches. Differences were due to eight instances resulting in either ecologically driven morphological diversification of species or morphologically cryptic species, uncovering hidden diversity. An interspecific genetic distance of at least 8% was observed with a clear barcoding gap for molecular delimitation of cumacean species. Combining these findings with data from public databases and specimens collected during different international expeditions revealed a change in the composition of taxa from a Northern Atlantic-boreal to an Arctic community. The Greenland-Iceland-Scotland-Ridge (GIS-Ridge) acts as a geographical barrier and/or predominate water masses correspond well with cumacean taxa dominance. A closer investigation on species level revealed occurrences across multiple ecoregions or patchy distributions within defined ecoregions.publishedVersio

A mega-cryptic species complex hidden among one of the most common annelids in the North East Atlantic

[Abstract] We investigate mitochondrial (COI, 16S rDNA) and nuclear (ITS2, 28S rDNA) genetic structure of North East Atlantic lineages of Terebellides, a genus of sedentary annelids mainly inhabiting continental shelf and slope sediments. We demonstrate the presence of more than 25 species of which only seven are formally described. Species boundaries are determined with molecular data using a broad range of analytical methods. Many of the new species are common and wide spread, and the majority of the species are found in sympatry with several other species in the complex. Being one of the most regularly encountered annelid taxa in the North East Atlantic, it is more likely to find an undescribed species of Terebellides than a described one.Funding: Financial support was provided by the Norwegian Taxonomy Initiative [http://www.biodiversity.no/Pages/135523] to AN (Cryptic polychaete species in Norwegian waters, knr 49-13, pnr 70184228), to EO, TB and JAK (Polychaetes in Skagerrak, knr 53-09, pnr 70184216), to TB, EO and JAK (Polychaetes in the Norwegian Sea, knr 55-12, pnr 70184227); and by the Swedish Taxonomy Initiative [https://www.artdatabanken.se/en/the-swedish-taxonomy-initiative/] (Polychaete species complexes in Swedish waters, dnr 140/07 1.4 and 166/08 1.4), and Kungliga Fysiografiska sällskapet Nilsson-Ehle donationerna [https://www.fysiografen.se/sv/] to AN; and by the ForBio Research School funded by the Research Council of Norway [https://www.forskningsradet.no/en/Home_page/1177315753906] (project no. 248799) and the Norwegian Taxonomy Initiative (pnr 70184215) and the Ramon y Cajal program (RYC-2016-20799) funded by Spanish Ministerio de Economía, Industria y Competitividad, Agencia Estatal de Investigación, Comunidad Autónoma de las Islas Baleares and the European Social Fund to MC; and by Akvaplan Niva [http://www.akvaplan.niva.no/en/] to AS and JP. Publication fees were covered by NTNU's [https://www.ntnu.no/] Publishing Fund to MC. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Acknowledgments We would like to give our greatest thanks to the staff and crew on all scientific expeditions mentioned in the material and method section. Special thanks to Stefan Agrenius for donating specimen 2045_4 from Byfjorden. We also would like to thank Juan Moreira (Universidad Autónoma de Madrid, Spain) for the line drawings in Fig 2.Norge. Norwegian Taxonomy Initiative; 70184228Norge. Norwegian Taxonomy Initiative; 70184216Norge. Norwegian Taxonomy Initiative; 70184227Norge. Norwegian Taxonomy Initiative; 70184215Sverige. Swedish Taxonomy Initiative; 166/08 1.4Sverige. Swedish Taxonomy Initiative; 140/07 1.4Norge. ForBio Research School; 24879

Original specimens and type localities of early described polychaete species (Annelida) from Norway, with particular attention to species described by O.F. Müller and M. Sars

Early descriptions of species from Norwegian waters are reviewed, with a focus on the basic requirements for reassessing their characteristics, in particular, by clarifying the status of the original material and locating sampling sites. A large number of polychaete species from the North Atlantic were described in the early period of zoological studies in the 18th and 19th centuries. The descriptions were often short or referred solely to general characteristics, which by today’s standards are considered inadequate for species discrimination. As a result, a number of taxa among the so-called ‘wellknown and widely distributed’ species have later been confused with morphologically similar species. Close to 100 presently valid species were described from Norwegian waters before 1900. The most prolific contributions were made by O.F. Müller (with about 20 species from 1771–1776) and Michael Sars (with more than 50 species from 1829–1872). Other authors in the 19th century included Anders Ørsted, Heinrich Rathke and Gerhard Armauer Hansen. Descriptions were mostly in Latin (O.F. Müller) or in Norwegian or Danish with the diagnosis in Latin (M. Sars and contemporary naturalists). Original material from O.F. Müller is not known to exist. Original material from M. Sars and contemporary scientists does still exist, but is often not identified as original (‘syntypes’) and is occasionally spread over several museum collections. Locating original sampling localities (‘type localities’) has been achieved by combining information from various literature sources, labels of original material (when extant), and knowledge of historic place names

Pseudoscalibregma Ashworth 1901

PseudoscalIbregma Ashworth, 1901 Pseudoscalibregma Ashworth, 1901: 296. Type species: Scalibregma parvum Hansen, 1879 Diagnosis (emended). Body elongate, posterior part tapering (‘arenicoliform’). Prostomium T-shaped with distinct lateral processes. Posterior parapodia with dorsal and ventral cirri. Branchiae absent. Large acicular spines absent; small thin, pointed or bifurcate spines present in chaetiger 1. Remarks. The diagnosis for the genus follows Blake (1981), with the exception of details concerning the presence of small spines in the first chaetiger as observed in the recently described species, P. orientalis from Japan (Imajima 2009) and in the type species P. parvum (present study, see below). The spines are similar to the thin spines in chaetigers 1–2 in species of Scalibregma that may be blunt or bifurcate. The spines are believed to be homologues of the furcate setae found in more posterior chaetigers (Mackie 1991).Published as part of Bakken, Torkild, Oug, Eivind & Kongsrud, Jon Anders, 2014, Occurrence and distribution of Pseudoscalibregma and Scalibregma (Annelida, Scalibregmatidae) in the deep Nordic Seas, with the description of Scalibregma hanseni n. sp., pp. 101-117 in Zootaxa 3753 (2) on page 102, DOI: 10.11646/zootaxa.3753.2.1, http://zenodo.org/record/22566