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

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

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

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

Scalibregma hanseni

ScalIbregma hansenI n. sp. Figures 4–6 Type locality. Norwegian continental shelf break, ‘Egga’, west of Nordland County, 68 ° 50.42 'N 13 °05.22'E, 765 m. Type material. Holotype (ZMBN 94016), MAREANO Sta. R 351-355, RP, 29 Oct. 2008, complete specimen, female with eggs in body cavity, in ethanol; 5 paratypes (ZMBN 94017), same sample as holotype, in ethanol; 1 paratype (ZMBN 94018), same sample as holotype, mounted for SEM; 1 paratype (ZMBN 94019), 1 paratype (ZMBN 94021) MAREANO Sta. R 351-356, RP, from type locality, 29 Oct. 2008, in ethanol; 1 paratype (ZMBN 94020), same sample as previous, mounted for SEM. Other material. R/V ‘ Håkon Mosby ’ stations: Sta. 81.03. 21.1, Lat: 63.166 Long: 0 4.816, 830 m, - 0.9 °C, 21 Mar. 1981, 2 spms; Sta. 81.06.0 6.3, Lat: 65.686 Long: 0 5.633, 602 m, 0.3 °C, 6 June 1981, 1 spm; Sta. 81.08. 16.7, Lat: 62.553 Long: 0 0.981, 800 m, - 0.9 °C, 3 spms; Sta. 82.01. 20.4, Lat: 62.495 Long: 0 2.136, 497 m, 2.2 °C, 20 Jan. 1982, 1 spm; Sta. 82.01. 21.2, Lat: 62.491 Long: 0 1.721, 604 m, 1.1 °C, 21 Jan. 1982, 10 spms; Sta. 82.01. 21.4, Lat: 62.560 Long: 0 0.981, 804 m, - 0.9 °C, 21 Jan. 1982, 1 spm; Sta. 82.11. 27.1, Lat: 62.985 Long: 0 3.218, 804 m, - 1.0°C, 27 Nov. 1982, 11 spms; Sta. 83.06.0 2.1, Lat: 62.198 Long: -00.003, 708 m, - 0.3 °C, 2 June 1983, 5 spms; Sta. 83.06.0 2.1, Lat: 62.198 Long: -00.003, 708 m, - 0.3 °C, 2 June 1983, 5 spms; Sta. 83.06.0 3.2, Lat: 60.201 Long: -06.625, 1220 m, - 0.8 °C, 3 June 1983, 4 spms; Sta. 83.06. 17.3, Lat: 62.593 Long: 0 1.233, 781 m, - 0.9 °C, 17 June 1983, 17 spms; Sta. 84.05. 23.1, Lat: 62.585 Long: 0 1.793, 656 m, - 0.8 °C, 23 May 1984, 3 spms; Sta. 84.05. 23.2, Lat: 62.590 Long: 0 1.795, 650 m, 23 May 1984, 2 spms; Sta. 84.05. 23.3, Lat: 62.508 Long: 0 1.851, 576 m, - 0.4 °C, 23 May 1984, 4 spms; Sta. 84.05. 23.5, Lat: 62.603 Long: 0 2.233, 576 m, - 0.8 °C, 23 May 1984, 4 spms; Sta. 84.11. 21.2, Lat: 62.553 Long: 0 1.820, 625 m, - 0.8 °C, 21 Nov. 1984, 8 spms; Sta. 85.01.0 8.1, Lat: 62.525 Long: 0 1.443, 701 m, - 0.9 °C, 8 Jan. 1985, 5 spms (1 mounted for SEM); Sta. 85.01.0 8.2, Lat: 62.706 Long: 0 1.186, 897 m, - 0.9 °C, 8 Jan. 1985, 4 spms; Sta. 86.07. 25.1, Lat: 69.023 Long: -08.410, 879 m, - 0.6 °C, 25 July 1986, 7 spms; Sta. 86.07. 27.2, Lat: 70.810 Long: -09.728, 886 m, - 0.6 °C, 27 July 1986, 5 spms (1 mounted for SEM); Sta. 86.07. 27.5, Lat: 70.678 Long: 0 7.631, 1243 m, - 0.6 °C, 27 July 1986, 1 spm; Sta. 86.08. 15.5, Lat: 62.610 Long: 0 1.573, 654 m, - 0.9 °C, 15 Aug. 1986, 1 spm; Sta. 86.08. 15.7, Lat: 62.843 Long: 0 1.431, 951 m, - 0.9 °C, 15 Aug. 1986, 1 spm; Sta. 86.08. 17.5, Lat: 62.996 Long: 0 1.140, 1143 m, - 0.9 °C, 17 Aug. 1986, 2 spms; Sta. 86.08. 17.6, Lat: 62.691 Long: 0 1.756, 750 m, - 0.9 °C, 17 Aug. 1986, 16 spms. MAREANO stations: Sta. R 351-355, RP, Lat: 68.84033 Long: 13.08700, 765 m, 29 Oct. 2008, 9 spms; Sta. R 351-356, 68.84033 N 13.08700E, 765 m, 29 Oct. 2008, 8 spms; Sta. R 416 - 386, Lat: 71.93600 Long: 15.53133, 777 m, 22 April 2009, 10 spms; Sta. R 464 - 143, Lat: 71.33700 Long: 16.51324, 853 m, - 0.48 °C, 25 Sept. 2009, 2 spms. Environmental monitoring stations: Sta. OL-01, Lat: 63.48446 Long: 0 5.36994, 837 m, 17 June 2004, 2 spms; Sta. OL-04, Lat: 63.51289 Long: 0 5.37823, 858 m, 18 June 2004, 1 spm; Sta. OL-06, Lat: 63.52350 Long: 0 5.37058, 870 m, 18 June 2004, 2 spms; Sta. OL-08, Lat: 63.53813 Long: 0 5.38181, 852 m, 18 June 2004, 1 spm; Sta. OL- 13, Lat: 63.56073 Long: 0 5.39664, 883 m, 19 June 2004, 3 spm; Sta. V-07, Lat: 63.50149 Long: 0 5.65205, 591 m, 1 June 1991, 6 spms; Sta. V-09, Lat: 65.00138 Long: 0 5.00019, 757 m, 1 June 1998, 3 spms. Description. Length of entire specimens 7–10 mm for 35–41 segments, width up to 1.9 mm. Body arenicoliform, anterior part swollen, posterior region tapered (Fig. 4). Holotype 9.5 mm long for 38 chaetigers, maximum width 1.8 mm, body swollen at chaetigers 5–13. Prostomium T-shaped, with two long digitiform processes directed laterally or anterolaterally (Fig. 5 A). Eyes lacking. Peristomium achaetous, dorsally well-developed with two rings and partly covering posterior part of prostomium, ventrally narrow. Mouth ventral, rounded oval, with broad anterior and posterior lips. Proboscis occasionally everted, simple or folded with undulating rim. Peristomium and first chaetiger of about same width as posterior body. Following chaetigers gradually increasing in width, body swollen from chaetigers 5–7 to chaetigers 13–16 (Fig. 4 A). Anterior segments with four annuli, segments posterior to swollen part with 5–6 annuli. Body surface tessellate. Ventral side with medial longitudinal furrow with rounded borders. Furrow with row of squarish epidermal pads (‘ventral shields’), one pad per segment, pads mostly indistinct in swollen region and posterior part of body (Fig. 4 B). Pygidium rounded, with ventral furrow and about ten short dorsal and lateral lobes (Fig. 5 B). Anal cirri filiform, somewhat thicker distally than proximally, easily detached (Fig. 4 F). Number of cirri not ascertained, up to five observed. Three pairs of branchiae, situated on chaetigers 3–5. Branchiae mostly simple, consisting of 1–4 simple or partly subdivided filaments, arising posterior to notopodia (Fig. 5 C, D). Branchiae usually increasing in size from anterior to posterior. Parapodia in anterior third of body small, inconspicuous, with low, evenly rounded prechaetal lobes in both rami (Fig. 4 C). Parapodia gradually developing from chaetigers 10–12, becoming well-developed from about chaetigers 14–16 (Fig. 5 E, 4 D). Dorsal cirri appearing from chaetigers 13–14, short triangular on most of body, becoming lanceolate in far posterior chaetigers. Ventral cirri appearing from chaetigers 14–16, triangular in most anterior chaetigers, rapidly becoming more pointed to lanceolate in following chaetigers (Fig. 5 F). Dorsal and ventral cirri with internal glandular structure, yellow coloured in preserved specimens (Fig. 4 E). Papillate interramal sense organ from about chaetiger 15 to posterior end (Fig. 5 G–H). All chaetigers with slender capillaries in both rami. First and second chaetiger in addition with gently curved, thin, blunt-tipped spines anterior to capillaries (Fig. 6 A–C), first chaetiger with 4–6 spines in both rami, second chaetiger with 6–8 somewhat longer spines. Notopodial spines located in a slightly curved vertical row in lower part of chaetal fascicle, neuropodial spines in a vertical row anterior to capillaries. All following chaetigers with furcate chaetae in both rami, located in a vertical row anterior to capillaries. Chaetiger 3 with 7–8 furcate chaetae, further back 8–12 (Fig. 6 D–E). Tines of furcate chaetae of unequal lengths (ratio 1.15: 1.35), longest tine with thin whip-shaped distal part, inner margin of tines with strong comb of teeth (Fig. 6 E–F). Capillaries hirsute, blunt spines and furcate chaetae with even surface structure (Fig. 6). Colour. Alcohol-preserved specimens light grey-brownish. Dorsal and ventral cirri usually bright yellow to brownish from colouring of internal glandular structure. Some specimens with transverse bands of light brownish epidermal pads on swollen part of body. Holotype with yellow transversal pigment bands dorsally on chaetigers 3– 5, dorsal and ventral cirri in posterior body yellow. Reproduction. Ovigerous females observed in samples from continental shelf break off Nordland County at 68 ° N, 765 m, October 2008. Diameter of eggs up to 180 µm. Holotype with eggs 120–140 µm in diameter. Distribution. The species has been found on the continental slope in the eastern Norwegian Sea, from deep areas around Jan Mayen, and from a single record on the Wyville-Thomspon Ridge at 1220 m depth (Fig. 7 C). The depth range is 497–1243 m. Most samples are from the upper slope (600–800 m), coinciding with a transition zone from temperate North Atlantic water to cold Norwegian Sea water, with temperatures fluctuating around 0°C. Etymology. This species is named after Gerhard Armauer Hansen for his contribution on polychaetes in the Norwegian Sea. In his treatment of the polychaetes from the Norwegian North-Atlantic Expedition 1876–1878, he described Pseudoscalibregma parvum and provided a description of Scalibregma abyssorum, which may have included material of the present species (Hansen 1879, 1882). Remarks. Presently six species are considered valid in the genus Scalibregma. Four species are found in NE Atlantic and Arctic waters, viz. S. inflatum, S. robustum Zachs, 1925, S. wireni Furreg, 1925, and S. celticum Mackie, 1991, and two species are found in US coastal waters: S. stenocerum (Bertelsen & Weston, 1980), and S. californicum Blake, 2000. Scalibregma hanseni n. sp shares with S. stenocerum the possession of three pairs of branchiae (on chaetigers 3–5), whereas all other species have four pairs of branchiae. Scalibregma hanseni n. sp. differs from S. stenocerum by having short rather than long, slender prostomial horns, by lacking eyes, and by having rather simple branchiae with few branches in contrast to bushy, multibranched branchiae. Scalibregma hanseni n. sp., S. stenocerum and S. celticum all have smooth blunt spines on chaetigers 1 and 2. Mackie (1991) discussed the taxonomic relevance of spines on the most anterior chaetigers and their possible homology with furcate chaetae in more posterior chaetigers.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 pages 110-115, DOI: 10.11646/zootaxa.3753.2.1, http://zenodo.org/record/22566

Scalibregma Rathke 1843

ScalIbregma Rathke, 1843 Scalibregma Rathke, 1843: 182 –184.— Blake 2000: 132. Type species: Scalibregma inflatum Rathke, 1843 Diagnosis. Body elongate, arenicoliform. Prostomium T-shaped with distinct lateral horns. Parapodia of posterior segments with dorsal and ventral cirri, interramal papillae or cilia present; postchaetal lamellae absent. Branchiae present. Chaetae including capillaries, lyrate chaetae, and sometimes few inconspicuous spines, blunt or bifurcated among capillaries of chaetigers 1–2, representing precursors of lyrate chaetae; large conspicuous spines absent. Pygidium with long anal cirri (Blake 2000: 132).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 108, DOI: 10.11646/zootaxa.3753.2.1, http://zenodo.org/record/22566