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The aim of this study was to describe and analyze the structure, distribution, and temporal variation in the composition of benthic polychaeta and their relation to abiotic characteristics in marine sediments along the continental shelf of Bahia de Todos Santos, Baja California, Mexico. Benthic macrofauna and environmental variables were collected to coordinated with a long-term ocean monitoring project known as the Southern California Bight Regional Monitoring Program. A total of nineteen stations were collected in September 1998, twenty stations in November 2003, fifteen stations in December 2013 and sixteen stations in September 2018. These data were compared to assess the response of benthic polychaete assemblages to natural and human induced changes in sediment characteristics. All stations were sampled using a Van Veen grab (0.1 m2) at depths between 15 to 206 m. Sites were selected using a multiple density nested random-tessellation stratified design. Environmental parameters measured included depth (m), sediment grain size

Chaetopterus is a globally distributed genus of marine Annelida with a long history of taxonomic confusion. Here, we describe Chaetopterus bruneli sp. nov. from a depth of 350 m in the St. Lawrence Estuary, eastern Canada. The new species represents the northernmost record for Chaetopterus in the western Atlantic to date. The similar European species Chaetopterus norvegicus M. Sars, 1835 is resurrected from long-standing synonymy and redescribed from type material, and a lectotype is designated.

Este artículo contiene 27 páginas, 3 tablas, 19 figuras., Chaetopteridae forms a monophyletic clade showing an uncertain position within Annelida. The family has 75 ubiquitous species within four genera that cluster in two well-supported clades (Chaetopterus–Mesochaetopterus and Spiochaetopterus–Phyllochaetopterus) and includes several cryptic species complexes. Based on integrative taxonomy and supported by citizen science, here we describe one new and two unnamed species of Caribbean chaetopterids. Partial sequences from the nuclear 18S rRNA and mitochondrial Cytochrome Oxidase I genes of all known chaetopterid genera allowed us to (1) discuss the phylogeny of the family and (2) assign the three species into Mesochaetopterus (two) and Phyllochaetopterus (one). Mesochaetopterus stinapa, sp. nov. clearly diverged from all species of the genus, whereas Mesochaetopterus aff. xerecus forms a separate clade with Mesochaetopterus rogeri (Europe) and Mesochaetopterus xerecus (Brazil). Phyllochaetopterus aff. verrilli forms a separate clade with Phyllochaetopterus arabicus (Red Sea) and the closely related sequences from Hawai’i, Australia and French Polynesia attributed to Phyllochaetopterus verrilli (or cf. verrilli). Despite observing differences in morphology (e.g. palp colour pattern, presence or absence of eyespots, chaetal morphology and arrangement) and biogeographical distributions, only the erection of M. stinapa as a new species is well supported by the genetic distance, barcoding gap and species discrimination analyses. Our results emphasise the existence of cryptic species complexes within Mesochaetopterus and Phyllochaetopterus, whose taxonomy will require further morphological, biogeographical and molecular data to be resolved., This paper is a contribution of D. Martin and C. Romano to the Consolidated Research Group on Marine Benthic Ecology of the Generalitat de Catalunya (2017SGR378) and to the International Outgoing Fellowship from the People Programme (Marie S. Curie Actions) of the European Union’s Seventh Framework Programme (FP7/2007–2013) (www.DeepFall-project.eu) under the REA grant agreement N. PIOF-GA-2013–628146.

The porcellanid crab Polyonyx gibbesi Haig, 1956, an obligate symbiont of Chaetopterus cf. variopedatus (Renier, 1804) in the western Atlantic, is parasitized by a rare entoniscid isopod. Crabs from coastal North Carolina and Florida, U.S.A., were dissected and examined for this internal parasite in 1966 and 1967. Two of 83 crabs (2.4 %) and 3 of 100 (3.0 %) crabs from North Carolina and Florida, respectively, were parasitized. Only female parasites were found, including five immature and three mature specimens; one host was parasitized by three immature entonicisds simultaneously. One of the mature parasites was liberating epicaridium larvae and the others had developing eggs or larvae. Parasitized female crabs were all ovigerous; the parasites did not castrate the hosts. The parasite is identified as Entoniscus creplinii Giard and Bonnier, 1887, previously known only from Brazil, and the female is redescribed.

Introducción: Desde un punto de vista global, los poliquetos que habitan en la comunidad pelágica han sido poco estudiados, aunque son un eslabón importante en las cadenas alimentarias de los ecosistemas marinos. Objetivo: Este trabajo contribuye al conocimiento de esta importante comunidad, analizando la riqueza y la densidad de los poliquetos. Métodos: Las muestras de plancton se tomaron en 17 localidades durante mayo y diciembre de 2013 en el área de estudio, mediante arrastres superficiales en una embarcación con un motor fuera de borda. Utilizamos una red con un diámetro de boca de 0.3 m, una longitud de 1.30 m y una abertura de malla de 0.3 mm. De cada muestra recolectada, los poliquetos se separaron y determinaron al nivel taxonómico más bajo posible. Resultados: Cuantificamos un total de 1873 individuos, con una variación importante en la densidad relativa, ya que en mayo se registraron 7 952.0 ind/100m3, mientras que en diciembre solo hubo 882.1 ind/100m3. Se analizaron las diferencias en la composición y densidad de los poliquetos determinados, de los cuales la proporción más alta pertenece a las formas larvales de las poblaciones bentónicas (meroplancton) y la más baja a los organismos del holoplancton. Durante los dos periodos de estudio se observaron trece familias, de las cuales, Sabellariidae, Spionidae, Chaetopteridae, Magelonidae, Iospilidae y Typhloscolecidae fueron comunes en ambos periodos, mientras que Aphroditidae, Syllidae, Phyllodocidae y Alciopidae fueron exclusivas de mayo y Serpullidae, Sabellidae y Lopadorhynchidae solo se encontraron en diciembre. Conclusiones: Es importante señalar que las variaciones observadas proporcionan valiosa información sobre los ciclos de vida y los aspectos biogeográficos de los poliquetos en el área de estudio.

In Australia, the deep-water (bathyal and abyssal) benthic invertebrate fauna is poorly known in comparison with that of shallow (subtidal and shelf) habitats. Benthic fauna from the deep eastern Australian margin was sampled systematically for the first time during 2017 RV ‘Investigator’ voyage ‘Sampling the Abyss’. Box core, Brenke sledge, and beam trawl samples were collected at one-degree intervals from Tasmania, 42°S, to southern Queensland, 24°S, from 900 to 4800 m depth. Annelids collected were identified by taxonomic experts on individual families around the world. A complete list of all identified species is presented, accompanied with brief morphological diagnoses, taxonomic remarks, and colour images. A total of more than 6000 annelid specimens consisting of 50 families (47 Polychaeta, one Echiura, two Sipuncula) and 214 species were recovered. Twenty-seven species were given valid names, 45 were assigned the qualifier cf., 87 the qualifier sp., and 55 species were considered new to science. Geographical ranges of 16 morphospecies extended along the eastern Australian margin to the Great Australian Bight, South Australia; however, these ranges need to be confirmed with genetic data. This work providing critical baseline biodiversity data on an important group of benthic invertebrates from a virtually unknown region of the world’s ocean will act as a springboard for future taxonomic and biogeographic studies in the area.

Chaetopterus bruneli sp. nov. urn:lsid:zoobank.org:act: A18C3F2E-B79B-4617-9E06-E1C665C9729A Figs 2, 3B Diagnosis Small, epifaunal Chaetopterus inhabiting a pale cream to tan, laminated, crescent-shaped tube. Segmental distribution 9A+5B+4–6C. Neuropodia absent in region A. Parapodia of B1 not posteriorly displaced from segment A-last. Segment B2 short, dorsal surface not fleshy. B1 and B2 neuropodia with four completely unfused, discrete lobes. With 3–8 small, light brown cutting notochaetae on segment A4, in an inconspicuous ventral fascicle. Uncini tooth distribution as follows: A9 neuropodia absent, B1 anterior lobe with 6–8 teeth, B1 posterior lobe with 5–7, B3 piston tori with 5–6, B3 ventral lobes with 5 teeth, C1 lateral lobes with 6–7, C1 ventral lobes with 8–10 teeth. Etymology This species is named in honour of Dr. Pierre Brunel, Université de Montréal, who has made a significant contribution to the study of deep-water benthic invertebrate communities in the Estuary and Gulf of St. Lawrence (EGSL) during his career. The specific epithet is a noun in the genitive case. Material examined Holotype CANADA • St. Lawrence Estuary, epifaunal on surface of muddy sediment; 48.7033º N, 68.5663º W; depth 350 m; 13 May 1992, Jean-Marc Gagnon leg.; CMNA 2015-0016. Paratypes CANADA • 10 specs; same collection data as for holotype; CMNA 2015-0001 to CMNA 2015-0004, CMNA 2015-0011 to CMNA 2015-0015, CMNA 2015-0017 • 3 specs; same collection data as for holotype; 1 Nov. 1990; CMNA 2015-0005 to CMNA 2015-0007 • 3 specs; same collection data as for holotype; 16 May 1991; CMNA 2015-0008 to CMNA 2015-0010 • 1 spec.; same collection data as for holotype; 15 Oct. 1993; CMNA 2015-0018. All type specimens and associated slide preparations are deposited in the Canadian Museum of Nature. Description (holotype) Mean and range values are given in parentheses for the holotype and six paratypes. Uncini data are based on paratype specimen CMNA 2015-0018, and their tooth counts and measurements are given in Table 1. GROSS MORPHOLOGY AND PRESEGMENTAL STRUCTURES. Small, epibenthic Chaetopterus, 10.5 mm total body length for 19 chaetigers (mean 11.6 mm, range 8.0–15.0 mm, n = 7); segmental formula 9–10A+5B+5– 6C. Peristomium ventrally narrow, horseshoe-shaped in dorsal view, with narrow dorsolateral lobes that sometimes obscure A1 notopodia, without pigment in preserved specimens. Grooved palps short and stout, inserted at dorsal inner margins of peristomium, 2.1 mm in length (mean 2.1 mm, range 2.0– 2.5 mm). Eyes absent. REGION A. Anterior region with 9 segments (Fig. 2A; 10 chaetigers on one side in paratype CMNA 2015-0005); 3.0 mm in length (mean 3.2 mm, range 2.0–4.0 mm, n = 7) and 4.0 mm in width (mean 4.5 mm, range 3.5–5.5 mm, n = 7), wider than long. Ventral surface of A with broad, triangular glandular shield, widest anteriorly and narrowing posteriorly to A9 (Fig. 2B). Region A notopodia shortest at A1 or A9, longest at A5 or A6 and decreasing in length again to segment A9; A4 notopodia shorter than neighboring notopodia. Small swellings not visible at dorsal base of A notopodia. Segment A4 notopodia bearing 3–8 relatively small, apically blunt translucent yellow cutting chaetae, with a distinct ventral tooth, on the ventral side of the notopodia (Fig. 2C). Other notopodia and the distal side of A4 notopodia bear lanceolate and simple chaetae (Fig. 2C). Region A chaetigers uniramous, A9 without neuropodia or uncini (Figs 2B, 3B). REGION B. Middle body region 6 mm in length (mean 5.9 mm, range 4.5–7.0 mm, n = 7). B1 with long aliform notopodia, approximately the length of region A (2.0–4.0 mm), reaching anteriorly to the peristomium (Fig. 2A). B1 and B2 neuropodia bilobed, with four completely unfused, discrete lobes, with uncini on distal lobe margins (Figs 2B, 3B). Anterior pair of neuropodial lobes in B1 narrow and situated medially (Figs 2B, 3B); uncini pyriform to D-shaped, apically rounded and pointed or rounded at base, widest slightly below middle (Fig. 2E). Posterior neuropodial lobes of B1 broader than anterior lobes and situated laterally (Figs 2B, 3B), uncini ellipsoid to D-shaped, apically blunt and rounded and pointed at base, widest at middle or slightly below (Fig. 2F). Segment B2 short relative to total body length; neuropodia bilobed with four completely unfused, discrete lobes; anterior pair of lobes situated more laterally than posterior pair of lobes (Fig. 2B). Neuropodia of B3–B5 each with a single pair of well-developed, unfused lobes, bearing uncini on posterior margins. Uncini of B3 piston tori ellipsoid to pyriform, apically rounded and rounded or pointed at base, widest at middle, proximal margin sometimes with a medial notch (Fig. 2G). B3 ventral lobe uncini ellipsoid to pyriform, apically blunt and pointed at base, widest at middle or slightly below, proximal margin with a medial notch (Fig. 2H). REGION C. Posterior body region 1.5 mm in length (range 1.5–4.0 mm, n = 7), with 4–6 chaetigers. Region C notopodia long and club-shaped, constricted at the base and widening distally, with internal simple notochaetae (Fig. 2 A–B); C1 notopodia 2.0 mm in length (mean 3.0 mm, range 2.0–4.0 mm, n = 7). Neuropodia bilobed, ventral lobes medially fused after C1 by a thin membrane, C1 ventral neuropodial lobes broader than those in succeeding segments; lateral lobes of C neuropodia lacking dorsal and ventral cirri. Both neuropodial lobes bear a row of uncini on distal margin. C1 lateral lobe uncini asymmetrically pyriform to ellipsoid, apically rounded and pointed at base, widest at middle or slightly below, with curved proximal margin (Fig. 2I). C1 ventral lobe uncini long ellipsoid to D-shaped, apically blunt and pointed at base, widest at middle or slightly above (Fig. 2J). TUBE. Tube short and curved, pale cream to tan, thin and composed of laminated proteinaceous material, externally covered in mud (Fig. 2D). Ecology and distribution The new species is known only from the type locality in the lower St. Lawrence Estuary, epibenthic on fine sediments at a depth of 350 m. Tubes resembling those of this species were also observed on bottom photographs from stations 18 and 20, at 390 and 331 m depth, respectively (Belley et al. 2010). In the late spring to early autumn of 1990 and 1991, several physico-chemical and biological measures were studied near the type locality of C. bruneli sp. nov. in the lower St. Lawrence Estuary (Station 26 in Savenkoff et al. 1994). These measurements were collected around the same time as some of the type specimens presented here. At that time, the type locality was in an upwelling area of the Laurentian trough, characterized by moderate productivity, low vertical stratification, higher salinity, and lower temperatures compared to the more productive plume region downstream (Savenkoff et al. 1994). The bottom water in the lower St. Lawrence Estuary is now being reported as increasingly and persistently hypoxic in recent years (Belley et al. 2010; Gilbert et al. 2005), which may explain why attempts to recollect this species from the type locality in September 2015 and August 2020 proved unsuccessful. Future benthic surveys of the St. Lawrence Estuary and Gulf of St. Lawrence may provide revised information about the distribution of this species. Remarks Chaetopterus bruneli sp. nov. is likely closely related to C. norvegicus. A summary of morphological features for both species is given in Tables 1 and 2. These species are unusual among described species of Chaetopterus for having unfused neuropodial lobes in segments B1 and B2 (see Discussion). Chaetopterus bruneli sp. nov. differs from C. norvegicus by its smaller body size, its lack of neuropodia in tagma A, and by its club-shaped notopodia and fewer chaetigers in tagma C. Chaetopterus bruneli sp. nov. builds mud-covered tubes on the surfaces of fine sediments at upper continental slope depths, whereas C. norvegicus is found in rocky areas on hard substrates at continental shelf depths, with little sediment on the external surface of the tubes. Some characters distinguishing these species may vary ontogenetically in Chaetopterus, including the body size and the number of segments in tagma C. There is, however, evidence from studies on the development of Chaetopterus that the neuropodia in the anterior tagma are present one day postmetamorphosis in a species that bears these structures as adults (Irvine et al. 1999: fig. 8b). Thus, the absence of neuropodia in tagma A should be reliable for distinguishing post-settlement individuals. While no mature gonads were observed in the preserved material of C. bruneli sp. nov., long-term preservation in alcohol can sometimes make distinguishing fat deposits from gametes difficult in specimens of Chaetopterus. The specimens of C. bruneli sp. nov. described here were collected over several seasons over two years and do not vary substantially in their morphology, nor in size. Genetic evidence is not available, as the specimens were preserved in formalin and no new material is available for tissue collection. The morphological and ecological differences between these species outlined above are substantial enough to provide sufficient grounds for the establishment of a new species. Only one other described species of Chaetopterus, C. longipes Crossland, 1904, lacks neuropodia in tagma A (Fig. 3C). Chaetopterus longipes was originally described from the Maldive Archipelago and was redescribed from Japanese material (Nishi 1996). Phylogenetic analyses suggest that C. longipes may represent a species complex distributed in both the tropical Indo-Pacific and Caribbean (Moore et al. 2017). Like C. norvegicus, C. longipes builds epibenthic tubes; these, however, occur gregariously and are embedded within elevated crevices on rocky coral reef substrates or found attached to the undersides of rocks rather than on the surface of soft sediments (Nishi 1996, 2001). Neither C. bruneli sp. nov. nor C. norvegicus are known to occur gregariously. C. bruneli sp. nov. lacks the fused, suckerlike neuropodia of segments B1 and B2 that are present in C. longipes and in most other species of Chaetopterus (Fig. 3). There are no records of any Chaetopterus species lacking neuropodia in tagma A north of 33º N latitude. The morphological and ecological differences among these species warrant the establishment of a distinct taxon, C. bruneli sp. nov., Published as part of Moore, Jenna M., Gagnon, Jean-Marc & Petersen, Mary E., 2020, A new species of Chaetopterus (Annelida: Chaetopteridae) from eastern Canada, with a redescription of Chaetopterus norvegicus M. Sars, 1835, pp. 19-34 in European Journal of Taxonomy 720 on pages 26-30, DOI: 10.5852/ejt.2020.720.1111, http://zenodo.org/record/4068434, {"references":["Belley R., Archambault P., Sundby B., Gilbert F. & Gagnon J. - M. 2010. Effects of hypoxia on benthic macrofauna and bioturbation in the Estuary and Gulf of St. Lawrence, Canada. Continental Shelf Research 30: 1302 - 1313. https: // doi. org / 10.1016 / j. csr. 2010.04.010","Sars M. 1835. Beskrivelser og Iagttagelser over nogle moerkelige eller nye i havet ved den bergenske kyst levende dyr af polypernes, acalephernes, radiaternes, annelidernes, og molluskerns classer, med en kort oversigt over de hidtil af forfattern sammesteds fundne arter og deres forkommen. Thorstein Hallagers Forlag hos Chr., Bergen.","Crossland C. 1904. The Polychaeta of the Maldive Archipelago from the collections made by J. Stanley Gardiner in 1899. Proceedings of the Zoological Society of London 1: 270 - 286. https: // doi. org / 10.1111 / j. 1469 - 7998.1904. tb 08291. x","Savenkoff C., Comeau L., Vezina A. F. & Gratton Y. 1994. Seasonal Variation of the Biological Activity in the Lower St. Lawrence Estuary. Canadian Technical Report of Fisheries and Aquatic Sciences 2006, Marine Environmental Sciences Branch, Mont joli (Quebec).","Gilbert D., Sundby B., Gobeil C., Mucci A. & Tremblay G. - H. 2005. A seventy-two-year record of diminishing deep-water oxygen in the St. Lawrence estuary: The northwest Atlantic connection. Limnology and Oceanography 50: 1654 - 1666. https: // doi. org / 10.4319 / lo. 2005.50.5.1654","Irvine S. Q., Chaga O. & Martindale M. Q. 1999. Larval ontogenetic stages of Chaetopterus: Developmental heterochrony in the evolution of chaetopterid polychaetes. Biological Bulletin 197: 319 - 331. https: // doi. org / 10.2307 / 1542786","Nishi E. 1996. Dense aggregation of Chaetopterus longipes Crossland, 1904 (Chaetopteridae, Polychaeta) in coral reefs at Okinawa, Japan. Natural History Research 4: 41 - 47. https: // doi. org / 10.13140 / 2.1.3180.0005","Moore J. M., Nishi E. & Rouse G. W. 2017. Phylogenetic analyses of Chaetopteridae (Annelida). Zoologica Scripta 46: 596 - 610. https: // doi. org / 10.1111 / zsc. 12238","Nishi E. 2001. Partial revision of Japanese Chaetopterus (Chaetopteridae, Polychaeta), including description of three new species from southern Pacific side of central Japan. Actinia 14: 1 - 26."]}

Chaetopterus norvegicus M. Sars, 1835, reinstated Figs 1, 3A Chaetopterus norvegicus M. Sars, 1835: 54–58, pl. 11, Fig. 29a–h. Chaetopterus norvegicus – Ørsted 1844: 78; 1845: 414. — McIntosh 1857: 126. — M. Sars 1860: 86. — Danielssen 1861: 52. — Quatrefages 1866: 214. — Malmgren 1867: 88. — G.O. Sars 1873: 261. — Jensen & Frederiksen 1992: 66. Tricoelia norvega – Meneghini 1847: 38. Chaetopterus variopedatus – Joyeux-Laffuie 1890: 345–351. — Lo Bianco 1893: 35. — de Saint- Joseph 1894: 148. — McIntosh 1915: 120. — Fauvel 1927: 77–78. non Tricoelia variopedata Renier, 1804: 18. Diagnosis Small- to medium-bodied, epifaunal Chaetopterus inhabiting a pale cream to brown, laminated, straight or bent tube. Segmental distribution 9A+5B+7–12C. Last segment of region A bearing neuropodia. Parapodia of B1 not posteriorly displaced from segment A-last. Segment B2 short, dorsal surface not fleshy. B1 and B2 neuropodia with four completely unfused, discrete lobes. With 5–10 relatively large light brown cutting notochaetae on segment A4, in a conspicuous ventral fascicle. Uncini tooth distribution as follows: A9 with 6–9 teeth, B1 anterior lobe with 7–9, B1 posterior lobe with 6–8, B3 piston tori with 7–9, B3 ventral lobes and C1 lateral lobes with 6–9, C1 ventral lobes with 8–12 teeth. Material examined Lectotype (here designated) NORWAY • one complete specimen preserved within tube fragment; Bergensfjord; depth 30–60 fathoms [54–110 m]; from original syntype lot NHMO C5877; NHMO C7049. Paralectotypes (here designated) NORWAY • 8 fragments and tube fragments; same collection data as for lectotype; from original syntype lot; NHMO C5877. Other material NORWAY • 4 fragments; Hardangersfjord, Rute H05-59; depth 30–42 m; 21 Oct 1958; LACM uncataloged specimens Pol2 Z76/58. Additional known material The following specimens were examined and identified as Chaetopterus norvegicus by M.E. Petersen; however, their current location was not verified or ascertained. We include them here to contribute additional distributional information for this species: SWEDEN • 1 spec.; Gullmarfjord, Humlesäcken; depth 30–50 m; 17 Sep. 1984; Claus Nielsen leg., from dredged material housed at the Kristineberg Marine Station • 3 specs; Gullmarfjord, Ös ̂ Holme; depth 37–40 m; 16 Sep. 1969; Claus Nielsen leg.; stones and shells. DENMARK • 3 specs; Herthas Flak; depth 15–20 m; 19 Jun. 1971. Description Based mostly on lectotype and paralectotypes. Uncini data based on LACM specimens, and their tooth counts and measurements are given in Table 1. GROSS MORPHOLOGY AND PRESEGMENTAL STRUCTURES. Small to medium-sized epibenthic Chaetopterus, 26 mm total body length for 26 chaetigers in lectotype, segmental formula 9A+5B+7–12C. Peristomium ventrally broad, horseshoe-shaped in dorsal view, with broad dorsolateral lobes that sometimes obscure A1 notopodia, sometimes with medium-brown pigment on dorsal surface. Grooved palps short, thin and filiform, inserted at dorsal inner margins of peristomium, 1.5 mm in length (n = 5). Eyes small, faint black spots positioned laterally near the outer base of the palps and obscured by the laterodorsal lobes of the peristomium. REGION A. Anterior region with 9 segments (Fig. 1A); 4.9 mm mean length (range 4.5–6 mm, n = 6) and 4.5 mm mean width (range 3–6 mm, n = 6), slightly longer than wide or as wide as long; ventral surface of A with broad, rectangular glandular shield (Figs 1B, 3A). Region A notopodia shortest at A1 or A4, increasing from A4 to a maximum at A6 and decreasing in length again to segment A9; A4 notopodia shorter than neighboring notopodia. Small swellings not visible at dorsal base of A notopodia. Segment A4 notopodia bearing 5–10 relatively large apically blunt, light brown, cutting chaetae, with a distinct ventral tooth, on the ventral side of the notopodia (Fig. 1A). Other notopodia and the distal side of A4 notopodia bear lanceolate and simple chaetae. Region A chaetigers uniramous except the last, A9, also with fan-shaped neuropodia in 4 of 5 specimens; mean width 1.3 mm (range 1–1.5 mm, n = 4) and furnished with uncini on posterior margin (Figs 1B, 3A). A9 uncini asymmetrically pyriform to D-shaped, apically blunt and pointed at base, widest at middle or slightly below, with a curved proximal margin (Fig. 1D). REGION B. Middle body region 10 mm in length in complete specimen. B1 with long aliform notopodia, 6 mm mean length (range 5–7 mm, n = 6), reaching anteriorly to the peristomium (Fig. 1 A–B). B1 and B2 neuropodia bilobed, with four completely unfused, discrete lobes, with uncini on distal lobe margins (Figs 1B, 3A). Anterior pair of neuropodial lobes in B1 narrow and situated medially (Figs 1B, 3A); uncini ovate to D-shaped, sometimes slightly pyriform, apically blunt and pointed or rounded at base, widest at middle or slightly below (Fig. 1E). Posterior neuropodial lobes of B1 broader than anterior and situated laterally (Figs 1B, 3A); uncini asymmetrically pyriform to ovate, apically blunt and pointed or rounded at base, widest at middle or slightly below, with a curved proximal margin (Fig. 1F). Segment B2 relatively short, 5 mm in length in one posterior fragment specimen; neuropodia bilobed with four completely unfused, discrete lobes; anterior pair of neuropodial lobes situated more laterally than posterior pair. Neuropodia of B3–B5 with a single pair of short, medially fused and ridge-like lobes, bearing uncini on posterior margins. B3 uncini of piston tori ovate to D-shaped, apically blunt and pointed at base, widest at middle, with straight proximal margin (Fig. 1G). B3 ventral lobe uncini asymmetrically pyriform to D-shaped, apically blunt and pointed at base, widest at middle or slightly below, with straight proximal margin (Fig. 1H). REGION C. Posterior body region mean length 6 mm (range 2–10 mm, n = 4), with 7–12 chaetigers. Region C notopodia long and thin, tapering evenly to apex; C1 notopodia mean length 3.3 mm (range 2.5–4.5 mm, n = 4). Neuropodia bilobed, ventral lobes medially unfused, C1 ventral neuropodial lobes broader than those in succeeding segments; lateral lobes of C neuropodia lacking dorsal and ventral cirri, one specimen with small dorsal inflations on dorsal margin of lateral lobes. Both neuropodial lobes bear a row of uncini on distal margin. C1 lateral lobe uncini asymmetrically pyriform to D-shaped, apically blunt and pointed at base, widest at middle or slightly below, with straight or curved proximal margin (Fig. 1I). C1 ventral lobe uncini long D-shaped, apically blunt and pointed or rounded at base, widest at middle, sometimes with marked curvature toward proximal side (Fig. 1J). TUBE. Tube straight or irregularly bent, pale cream-white and paper-like, very thin and delicate, composed of laminated proteinaceous material, without externally affixed sediment (Fig. 1C). COI barcode sequence GenBank ID DQ209254 (Osborn et al. 2007),as Chaetopterus sarsi M. Sars, 1860, from Trondheimsfjord, Norway, SAM E3557. Included in BOLD Barcode Index Number BOLD: AAW6559, identified from photographs. Ecology and distribution Chaetopterus norvegicus is an epifaunal species found on rocky substrates, sometimes among the branches of the coral Desmophyllum pertusum (Linnaeus, 1758) (Malmgren 1867, as Lophelia prolifera; Ørsted 1845, as Oculina prolifera; Jensen & Frederiksen 1992, as Lophelia pertusa), from depths of 30– 550 m. Chaetopterus norvegicus was recorded as a prey item of haddock, Melanogrammus aeglefinus (Linnaeus, 1758) by McIntosh (1857). Little else is known about its ecology. Reported from the North Sea and Arctic waters, west to the Faroe Islands (Jensen & Frederiksen 1992), with the northernmost reports from Karlŝ, near Tromsø in northern Norway; widespread in coastal Norway, including areas near Bergen, Oslo, and Trondheim; Koster, Väder̂arma and Gullmann in western Sweden, south to Kattegat (Malmgren 1867); not known from the Baltic Sea. Remarks The lectotype is delicate and in fair condition, and represents the sole complete specimen within the original syntype lot. The paralectotypes consist of the remaining original syntypes and are in a similar condition. To avoid destructive sampling of the original type material, we examined uncini from a Norwegian specimen in the collections of the LACM. The external morphological features of this specimen agree with those of the lectotype and paralectotypes. Three additional specimens of Chaetopterus norvegicus from Denmark and western Sweden were examined and figured in detail by the late M.E. Petersen (see Additional known material, above). The present location of these specimens is unknown, but the notes and drawings agree well with the features present in the type material. Chaetopterus norvegicus M. Sars, 1835 was the second species described within the genus Chaetopterus. The original description of Chaetopterus norvegicus is detailed and includes illustrations; however, Sars mistook the dorsal side for the ventral, and included segment B 1 in the anterior body region, as first remarked by Quatrefages (1866). Sars noted the apparent absence of eyes in C. norvegicus in his description; however, lateral eyespots appear in his later, unpublished figures of C. norvegicus (M. Sars ca 1870) and are faintly visible in the type specimens. Prior to this study, eight nominal species of Chaetopterus had been described from the North Atlantic, including the Caribbean, Mediterranean, and North Seas: C. variopedatus (Renier 1804), C. pergamentaceus Cuvier, 1830, C. norvegicus M. Sars, 1835, C. sarsii Boeck in Sars, 1860, C. insignis Baird, 1864, C. valencinii Quatrefages, 1866, C. quatrefagesi Jourdain, 1868, and C. brevis Lespés, 1872. Chaetopterus norvegicus is readily distinguishable from other North Atlantic species by its unfused neuropodia in segments B1 and B2, a character clearly shown in Sars’ figures (M. Sars 1835, ca 1870). All other species of Chaetopterus previously described from the North Atlantic possess fused, sucker-like neuropodia in segments B1 and B2 (but see below). The most recent phylogenetic analysis of the family recovered C. norvegicus in a clade including C. pugaporcinus Osborn, Rouse, Goffredi & Robison, 2007 and C. antarcticus Kinberg, 1866 (Moore et al. 2017; C. norvegicus is misidentified there as C. sarsii). This clade is sister to all other species of Chaetopterus, including C. variopedatus. Thus, genetic evidence does not support the long-standing synonymy of C. norvegicus with C. variopedatus. Additionally, several morphological features distinguish between these species. While the original description of C. variopedatus is brief and without figures (Renier 1804), the examination of six specimens of C. variopedatus from the Mediterranean and Adriatic Seas (USNM 5102, UF 4254 to UF 4258) revealed several characters clearly distinguishing these species. Chaetopterus variopedatus has a body size of 7–14 cm, medially fused, bilobed, sucker-like neuropodia in segments B1 and B2, and over 20 segments in tagma C. Furthermore, C. variopedatus secretes a large (~ 30 cm), infaunal tube of heavily laminated, flexible, brown parchment-like material covered externally in coarse sediment. Chaetopterus norvegicus, in contrast, has a body size of approximately 2–3 cm, distinctive unfused bilobed neuropodia in segments B1 and B2, 7–12 chaetigers in tagma C, and inhabits a relatively small, stiff, delicate and somewhat translucent white tube, and is epifaunal on hard substrates. The unusual unfused neuropodia of B 1 in C. norvegicus contrast with the sucker-like, fused neuropodia found in C. variopedatus and other species of Chaetopterus (Fig. 3). These strong genetic, morphological and ecological differences warrant the resurrection of C. norvegicus as a valid species., Published as part of Moore, Jenna M., Gagnon, Jean-Marc & Petersen, Mary E., 2020, A new species of Chaetopterus (Annelida: Chaetopteridae) from eastern Canada, with a redescription of Chaetopterus norvegicus M. Sars, 1835, pp. 19-34 in European Journal of Taxonomy 720 on pages 21-26, DOI: 10.5852/ejt.2020.720.1111, http://zenodo.org/record/4068434, {"references":["Sars M. 1835. Beskrivelser og Iagttagelser over nogle moerkelige eller nye i havet ved den bergenske kyst levende dyr af polypernes, acalephernes, radiaternes, annelidernes, og molluskerns classer, med en kort oversigt over de hidtil af forfattern sammesteds fundne arter og deres forkommen. Thorstein Hallagers Forlag hos Chr., Bergen.","Orsted A. S. 1844. De regionibus marinis. Elementa topographiae historiconaturalis freti Oresund. J. C. Sharling, Copenhagen.","Orsted A. S. 1845. Fortegnelse over Dyr, samlede i Christianiafjord ved Drobak fra 21 - 24 Juli, 1844. Naturhistorisk tidsskrift, KJObenhavn 2: 400 - 427.","McIntosh W. C. 1857. The Marine Invertebrates and Fishes of St. Andrews. Taylor & Francis, London.","Sars M. 1860. Uddrag af en Beskrivelse over Chaetopterus sarsii n. sp., og Chaetopterus norvegicus Sars. Forhandlinger fra Videnskabs-Selskabet i Christiania 1860: 85 - 88.","Danielssen D. C. 1861. Beretning om en zoologisk Reise foretagen i Sommeren 1857. Nyt Magazin for Naturvidenskaberne 11: 1 - 58.","Quatrefages A. 1866. Annelides et Gephyriens. Histoire naturelle des Anneles marins et d'eau douce. Annelides et Gephyriens. Volume 2. Premiere partie. Librairie encyclopedique de Roret, Paris.","Malmgren A. J. 1867. Annulata Polychaeta Spetsbergiae, Groenlandiae, Islandiae et Scandinaviae. Hactenus Cognita. Ex Officina Frenckelliana, Helsingforslae.","Sars G. O. 1873. Bidrag til Kundskab om ChristianiafJordens Fauna. J. Dahl, Christiania.","Jensen A. & Frederiksen R. 1992. The fauna associated with the bank-forming deepwater coral Lophelia pertusa (Scleractinaria) on the Faroe shelf. Sarsia 77: 53 - 69. https: // doi. org / 10.1080 / 00364827.1992.10413492","Meneghini G. & Renier S. A. 1847. Osservazioni postume de zoologia Adriatica. I. R. Istituto Veneto di Scienze, Lettere ed Arti, Venice, Italy.","Joyeux-Laffuie J. 1890. Etude monographique du Chetoptere (Chaetopterus variopedatus, Renier) suivie d'une revision des especes du genre Chaetopterus. Archives de zoologie experimentale et generale serie 2 8: 245 - 360.","Lo Bianco S. 1893. Gli anellidi tubicoli trovati nel Golfo di Napoli. Atti Della R. Accademia delle Scienze Fisiche e Matematiche 5: 1 - 97.","de St. Joseph A. A. 1894. Les Annelides polychetes des cotes de Dinard. Troisieme Partie. Annales des sciences naturelles, Paris, Serie 7 17: 1 - 395.","McIntosh W. C. 1915. Chaetopteridae. A Monograph of the British Marine Annelids: 115 - 132. The Ray Society, London.","Fauvel P. 1927. Polychetes sedentaires. Addenda aux Errantes, Archiannelides, Myzostomaires. Faune de France 16: 1 - 494.","Renier S. A. 1804. Prospetto della Classe dei Vermi, nominati el ordinati secondo il Sistemo de Bosc. XV-XXVIII. Padua.","Osborn K. J., Rouse G. W., Goffredi S. K. & Robison B. H. 2007. Description and relationships of Chaetopterus pugaporcinus, an unusual pelagic polychaete (Annelida, Chaetopteridae). Biological Bulletin 212: 40 - 54. https: // doi. org / 10.2307 / 25066579","Moore J. M., Nishi E. & Rouse G. W. 2017. Phylogenetic analyses of Chaetopteridae (Annelida). Zoologica Scripta 46: 596 - 610. https: // doi. org / 10.1111 / zsc. 12238"]}

Tilic, Ekin, Rouse, Greg W. (2020): Hidden in plain sight, Chaetopterus dewysee sp. nov. (Chaetopteridae, Annelida) - A new species from Southern California. European Journal of Taxonomy 643: 1-16, DOI: https://doi.org/10.5852/ejt.2020.643

We describe a long-unnamed Chaetopterus Cuvier, 1830 species from southern California, using a combination of DNA barcoding and detailed morphological investigation employing high-resolution X-ray microtomography (micro-CT). Chaetopterus dewysee sp. nov. is not only one of the most dominant annelids in the benthic communities of the shallow end of the La Jolla submarine canyon, but also a well-established model for studying bioluminescence and has a published transcriptome. The description and naming of this southern Californian Chaetopterus is a step towards the much-needed revision of the group’s taxonomy and towards resolving the confusion over the ʻcosmopolitanʼ Chaetopterus variopedatus species complex. Micro-CT data showing details of both internal and external anatomy has been made freely available as the first annelid cybertype.

A temporal analysis of the benthic polychaete community and its relationship with environmental variables was conducted by comparing coastal sediment samples collected in three separate sampling events between 1998 and 2013 from the southern end of the Southern California Bight (SCB). Environmental variables indicated a spatio-temporal increase of the sand fraction in sediment composition. Station stratification by depth from shallow to deep, and a reduction of trace metal enrichment (Co, Cr, Cu, Mn, Ni, Pb and Zn) was also found. There was a notable change in polychaete family composition due to high abundances and frequency of Spionidae, Chaetopteridae and Phyllodocidae in 2013, especially close to the Binational wastewater treatment plant discharge. An increase in polychaete abundance, richness and diversity was indicative of a probable relationship with regional weather conditions (El Niño-Southern Oscillation and recent drought events during sampling) along with local anthropogenic discharges of wastewater treatment plants in the area.

Introduction: The shelf-break frontal area in the Argentine Sea, between 37ｼ S and 40ｼ S, is characterized by high frequency and abundance of the parchment worm Chaetopterus antarcticus Kinberg, 1866 associated to Zygochlamys patagonica scallop beds. This polychaete was usually collected within its U tubes, typical of infaunal habit. During 2007, a surprising massive settlement of worms on scallops was observed. Objective: Our objectives is to report the variability of life habits of C. antarcticus in scallop grounds distributed between 37º S and 40º S in Argentinean waters. Methods: The presence of the parchment tube worms on Z. patagonica was analyzed in 892 scallops coming from three samples collected in September (previously obtained for other purposes) and November 2007 and April 2008, between 99-106 m depth in Management Unit B (16.186 km2, 38º S - 39º 52’ S). Polychaetes were identified and quantified on both valves. In addition, both epibiont and infaunal worms were registered through time. The settlement of C. antarcticus on scallops was monitored during the period 2007-2015 and the presence of free tubes, both empty and inhabited by worms, were registered during the period 2008-2015 from a total of 374 representative subsamples (10 l) collected with trawling tools between 37º S and 40º S. Results: Scallops collected in 2007 and 2008 showed that 468 (> 50 %) specimens were encrusted; in 66 % (311 specimens) of them C. antarcticus was settled. The temporal analysis showed that the spatial distribution of epibiotic worms decreased in 2009, 2010 and 2012, with its total absence in 2013, 2014 and 2015 in the study area. During the period 2007 - 2015, infaunal worms were registered throughout the area, collected in part of the locations monitored. Conclusions: The variability of life habits of C. antarcticus was not commonly registered previously in the study area; epibiotic behavior could be the result of intensive soft sediment disturbance due to trawling and hence, the selection of other available primary settlement substrate. Resumen Introducción: El área del frente de talud en el Mar Argentino, entre 37° S y 40° S, se caracteriza por alta frecuencia y abundancia del poliqueto Chaetopterus antarcticus Kinberg, 1866 asociado a bancos de vieira Zygochlamys patagonica (King, 1832). Este poliqueto era colectado usualmente habitando los tubos en U, típicos de hábito infaunal. Durante 2007, un sorprendente asentamiento masivo de gusanos sobre vieiras fue observado. Objetivos: Los objetivos del trabajo son reportar la variabilidad del hábito de vida de C. antarcticus en fondos de vieiras entre 37° S y 40° S en aguas de Argentina. Métodos: La presencia de gusanos tubícolas sobre Z. patagonica se analizó en 892 vieiras colectadas en tres muestras durante Septiembre (muestra tomada con otros propósitos) y Noviembre 2007 y Abril 2008, entre 99-106 m de profundidad en la Unidad de Manejo B (16.186 km2, 38º S - 39º 52’ S). Los poliquetos fueron identificados y cuantificados en ambas valvas. Además, los gusanos tanto epibiontes como infaunales se registraron en un período de tiempo. El asentamiento de C. antarcticus sobre vieiras se monitoreó durante 2007-2015 y la presencia de tubos libres, tanto vacíos como habitados por gusanos, durante 2008-2015 a partir de 374 submuestras representativas (10 l) colectadas con artes de arrastre entre 37° S y 40° S. Resultados: Las vieiras colectadas en 2007 y 2008 mostraron que 468 (> 50 %) especímenes estaban incrustados; C. antarcticus estaba asentado en 66 % (311 especímenes) de los mismos. El análisis temporal mostró que la distribución espacial de gusanos epibiontes decreció en 2009, 20101 y 2012, y su ausencia total en 2013, 2014 y 2015 en el área de estudio. Durante el período 2007 - 2015 los gusanos infaunales se registraron en toda el área, en parte de las localidades relevadas. Conclusiones: La variabilidad del hábito de vida de C. antarcticus no había sido registrada previamente en el área de estudio; el comportamiento epibiótico podría ser el resultado del disturbio intensivo de los sedimentos blandos debido al arrastre y en consecuencia, la selección de otro sustrato de asentamiento primario disponible.

Polyonyx socialis sp. n. from the South China Sea of Vietnam is described. The new species was collected in a previous study that compared the vertebrate and invertebrate symbiont communities living in the tubes of two syntopic species of the polychaete genus Chaetopterus. Polyonyx socialis sp. n. inhabits the tubes of the smaller polychaete species as a heterosexual pair, and frequently shares the cavity of the host's tube with a larger porcellanid, P. heok, also present as a male-female pair, and with a species of trinchesiid nudibranch. Less frequently, the new species shares its host with a heterosexual pair of a larger species of pinnotherid crab. Polyonyx socialis sp. n. belongs to the P. sinensis group, a world-wide distributed morphological line within the heterogeneous genus Polyonyx. Most species in this group are obligate commensals of chaetopterid polychaetes. The crabs have a transversally cylindrical habitus, which enables them to move laterally along the worm tubes with ease. Polyonyx socialis sp. n. is a relatively small species that lives attached to the inner walls of the polychaete tube. The small size and flattened chelipeds and walking legs of the new species confers it an advantage to cohabiting the same worm tube with larger decapod species occupying most of the tube's cavity.

Annelida is a highly diverse animal group with over 21,000 described species. As part of Lophotrochozoa, the vast majority of annelids are currently classified into two groups: Errantia and Sedentaria, together forming Pleistoannelida. Besides these taxa, Sipuncula, Amphinomidae, Chaetopteridae, Oweniidae and Magelonidae can be found branching at the base of the tree. Comparisons of mitochondrial genomes have been used to investigate phylogenetic relationship within animal taxa. Complete annelid mitochondrial genomes are available for some Sedentaria and Errantia and in most cases exhibit a highly conserved gene order. Only two complete genomes have been published from the basal branching lineages and these are restricted to Sipuncula. We describe the first complete mitochondrial genome sequences for all other basal branching annelid families: Owenia fusiformis (Oweniidae), Magelona mirabilis (Magelonidae), Eurythoe complanata (Amphinomidae), Chaetopterus variopedatus and Phyllochaetopterus sp. (Chaetopteridae). The mitochondrial gene order of all these taxa is substantially different from the pattern found in Pleistoannelida. Additionally, we report the first mitochondrial genomes in Annelida that encode genes on both strands. Our findings demonstrate that the supposedly highly conserved mitochondrial gene order suggested for Annelida is restricted to Pleistoannelida, representing the ground pattern of this group. All investigated basal branching annelid taxa show a completely different arrangement of genes than observed in Pleistoannelida. The gene order of protein coding and ribosomal genes in Magelona mirabilis differs only in two transposition events from a putative lophotrochozoan ground pattern and might be the closest to an ancestral annelid pattern. The mitochondrial genomes of Myzostomida show the conserved pattern of Pleistoannelida, thereby supporting their inclusion in this taxon.

Este capítulo contiene 78 páginas, 4 figuras, 7 tablas., Here we consider the growing knowledge on symbiotic polychaetes since this particular group of worms, and their relationships with their hosts, were reviewed by Martin & Britayev (1998). The current number of symbiotic polychaetes (excluding myzostomids) reported has almost doubled since 1998 (618 versus 373 species) and are now known to be involved in 1626 relationships (966 in 1998), representing 245 and 660 newly reported species and relationships, respectively. Overall, 490 (292 in 1998) species involved in 1229 (713 in 1998) relationships are commensals, and 128 (81 in 1998) involved in 397 (253 in 1998) relationships are parasitic. New commensal and parasitic species and/ or relationships have been respectively reported for eight (Chaetopteridae, Siboglinidae, Fabriciidae, Aphroditidae, Orbiniidae, Pholoididae, Scalibregmatidae, Sigalionidae) and five (Fabriciidae, Typhloscolecidae, Phyllodocidae, Polynoidae, Hesionidae, Serpulidae) polychaete families. Three additional taxa (cephalopod molluscs, gorgonocephalid ophiuroids and ascidian tunicates) are now known to harbour commensal polychaetes, and a further three taxa (decapod crustaceans, chaetognaths and brachiopods) are now known to host parasitic polychaetes. Here we discuss, family by family, the main characteristics and nature of symbiotic polychaetes and their relationships. We conclude that some of the biases identified in 1998 are still uncorrected. Despite the noticeable increase of taxonomic studies describing new species and reporting new relationships, there is still a lack of ecological and biological studies, either descriptive or experimental (e.g. based on behavioural observations of living organisms), addressing the actual nature of the associations. We have also identified that most studies are restricted to a specialised academic world. The next logical step would be to transfer this knowledge to non-specialised audiences. In other words, to contribute to the preservation of our seas, it is our duty to raise awareness of the potential ecological and economic impacts of these symbiotic associations and to allow other eyes to enjoy the intrinsic beauty of symbiotic worms., This paper is a contribution of D. Martin to the Research Projects MarSymbiOmics (CTM2013- 43287-P), funded by Spanish ‘Agencia Estatal de Investigación’ (AEI), and PopCOmics (CTM2017- 88080), funded by the AEI and the European Funds for Regional Development (FEDER), and to the Consolidated Research Group on Marine Benthic Ecology of the Generalitat de Catalunya (2017SGR378). The work of T.A. Britayev was supported by the research project 18-05-00459, funded by the Russian Scientific Foundation for Basic Science.

Sun, Y. and Qiu, J.-W. 2014. A new species of Chaetopterus (Annelida, Chaetopteridae) from Hong Kong. Memoirs of Museum Victoria 71: 303–309. A new species, Chaetopterus qiani sp. nov., is described based on 18 specimens collected from a fish farm in Hong Kong. This species is small (body length: 11. 5–35.5 mm), with nine, five and 10–16 chaetigers in regions A, B and C, respectively. It belongs to a small group of epibenthic Chaetopterus species with long notopodia in region C. This species can be distinguished from other epibenthic Chaetopterus by a combination of the following features: up to 16 lightbrownish cutting chaetae in A4, wide neuropodia in A9, large wing-shaped notopodia in B1, 10–16 chaetigers in region C, long club-shaped notopodia and a short conical dorsal cirrus in the dorsal lingule of neuropodia in region C. A key to Chaetopterus from the Pacific region is provided.

Este artículo contiene 24 páginas, 6 tablas, 7 figuras., To assess whether closely related host species harbour similar symbiotic communities, we studied two polychaetes, Chaetopterus sp. (n D 11) and Chaetopterus cf. appendiculatus (n D 83) living in soft sediments of Nhatrang Bay (South China Sea, Vietnam). The former harboured the porcellanid crabs Polyonyx cf. heok and Polyonyx sp., the pinnotherid crab Tetrias sp. and the tergipedid nudibranch Phestilla sp. The latter harboured the polynoid polychaete Ophthalmonoe pettiboneae, the carapid fish Onuxodon fowleri and the porcellanid crab Eulenaios cometes, all of which, except O. fowleri, seemed to be specialized symbionts. The species richness and mean intensity of the symbionts were higher in Chaetopterus sp. than in C. cf. appendiculatus (1.8 and 1.02 species and 3.0 and 1.05 individuals per host respectively). We suggest that the lower density of Chaetopterus sp. may explain the higher number of associated symbionts observed, as well as the 100% prevalence (69.5% in C. cf. appenciculatus). Most Chaetopterus sp. harboured two symbiotic species, which was extremely rare in C. cf. appendiculatus, suggesting lower interspecific interactions in the former. The crab and nudibranch symbionts of Chaetopterus sp. often shared a host and lived in pairs, thus partitioning resources. This led to the species coexisting in the tubes of Chaetopterus sp., establishing a tightly packed community, indicating high species richness and mean intensity, together with a low species dominance. In contrast, the aggressive, strictly territorial species associated with C. cf. appendiculatus established a symbiotic community strongly dominated by single species and, thus, low species richness and mean intensity. Therefore, we suggest that interspecific interactions are determining species richness, intensity and dominance, while intraspecific interactions are influencing only intensity and abundance. It is possible that species composition may have influenced the differences in community structure observed. We hypothesize that both host species could originally be allopatric. The evolutionary specialization of the symbiotic communities would occur in separated geographical areas, while the posterior disappearance of the existing geographical barriers would lead to the overlapped distribution., This work was suported by the Russian Science Foundation (grant no 14-14-01179), the Spanish Research Project MariSymBiomics (CTM2013-43287-P) and the Consolidated Research Group of Marine Benthic Ecology of the Generalitat de Catalunya (2014SGR120).

The family Oweniidae Rioja, 1917 is a small group of broadly distributed polychaetes whose relationships and position in the annelid tree are still poorly understood. A comprehensive revision of the group with reconsideration of character homologies and terminology under a phylogenetic framework was needed. We investigated the relationships of members of Oweniidae and other polychaetes by performing maximum parsimony analyses of 18 oweniid species of the five recognized genera to date and members of the families Siboglinidae, Sabellidae, Spionidae, Magelonidae, and Chaetopteridae. Phylogenetic hypotheses confirmed the monophyly of Oweniidae and suggested sister-group relationships with Magelonidae, although weakly supported. Analyses also recovered Owenia and Myriowenia as monophyletic and allowed recognition of Myrioglobula as a junior synonym of Myriochele based on the presence of acicular chaetae and the shape of the head. Implied weighting analyses supported these findings and recovered Galathowenia australis as sister group of Myriochele. The presence of acicular chaetae justifies the consideration of this species as belonging to Myriochele. Nomenclatural changes are proposed for those species previously considered as members of Myrioglobula, and these are: Myriochele antarcticacomb. nov., Myriochele japonicacomb. nov., Myriochele islandicacomb. nov., Myriochele malmgrenicomb. nov., and Myriochele australiscomb. nov. After analyses and definition of generic diagnostic features, other new combinations include Galathowenia eurystomacomb. nov. and Galathowenia haplosomacomb. nov., previously considered as members of Myriochele. Taxonomic revision of Australian collections revealed the presence of Myriochele heruensis Gibbs, 1971, which is herein redescribed, and allowed the description of four new species: Galathowenia annae sp. nov., Galathowenia arafurensissp. nov., Galathowenia quelissp. nov., and Myriochele australiensissp. nov., mostly from the east coast of Australia, in addition to the three recently well-documented species of Owenia. Australian species have been described, illustrated, and compared in detail with similar taxa. Distribution patterns and ecological notes have also been given. Keys to oweniid genera and Australian species are provided. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166, 236–278.

Seasonal changes of abundance and composition of planktonic polychaete larvae were investigated monthly from January 2007 to December 2009 in Onagawa Bay, northeastern Japan. Larvae belonging to 18 families were identified: Spionidae, Serpulidae, Nephtyidae, Magelonidae, Phyllodocidae, Polynoidae, Syllidae, Capitellidae, Nereididae, Terebellidae, Arenicolidae, Chaetopteridae, Oweniidae, Pectinariidae, Glyceridae, Dorvilleidae, Sabellidae, and Lumbrineridae. The density of polychaete larvae varied from 18 to 6901 ind m−3. Spionid larvae occurred throughout the year, being the dominant family throughout the year, comprising 88.7% of the total, with those belonging to genus Polydora dominant during winter to spring and Pseudopolydora during summer to autumn. Larvae belonging to the Serpulidae, Magelonidae, Nephtyidae, Phyllodocidae, and Polynoidae tended to be frequent in summer and autumn. The close timing between phytoplankton blooms and the production of planktonic polychaete larvae is discussed,...

Vestimentiferan tube worms living at deep-sea hydrothermal vents and cold seeps have been considered as a clade with a long and continuing evolutionary history in these ecosystems. Whereas the fossil record appears to support this view, molecular age estimates do not. The two main features that are used to identify vestimentiferan tubes in the fossil record are longitudinal ridges on the tube's surface and a tube wall constructed of multiple layers. It is shown here that chaetopterid tubes from modern vents and seeps—as well as a number of fossil tubes from shallow-water environments—also show these two features. This calls for a more cautious interpretation of tubular fossils from ancient vent and seep deposits. We suggest that: current estimates for a relatively young evolutionary age based on molecular clock methods may be more reliable than the inferences of ancient “vestimentiferans” based on putative fossils of these worms; not all of these putative fossils actually belong to this group; and that tubes from fossil seeps should be investigated for chitinous remains to substantiate claims of their potential siboglinid affinities.

The assemblage and the temporal changes of benthic macrofauna inhabiting the Phyllochaetopterus socialis (Polychaeta: Chaetopteridae) aggregates were analysed during 2004 and May 2005 in the Mar del Plata harbour, Buenos Aires (Argentina). Species composition, abundance, richness and diversity were estimated from monthly or bimonthly samples obtained by SCUBA diving. Multivariate (MDS) and SIMPER analyses were applied to analyse the structure of benthic communities. In the mats, a total of 57 species (invertebrates and chordates) belonging to 11 phyla were associated to P. socialis: crustaceans and molluscs were the most abundant species and crustaceans and polychaetes were the most diverse groups (14 and 11 species richness, respectively). The mean abundance ranged from 79.67±57.47 ind/250 ml to 718.75 ind/250 ml (mean±SD). The amphipod Monocorophium insidiosum, the gastropod Anachis isabellei and the tanaidacean Leptognathia sp. were the most representative species in the mats. Richness and diversity in P. socialis aggregates were higher than in surrounding sediments. Results show significant differences among months in composition, abundance and feeding guilds of the macrofauna associated with the mats. The assemblage of benthic macrofauna with permanent and temporary organisms in P. socialis aggregates suggests the existence of microhabitats in the mats that provide substrate, refuges for predation and availability of food increasing richness and diversity. These results allow considering P. socialis as an autogenic ecosystem engineer in the Mar del Plata harbour.

We provide descriptions of five species of Chaetopterus and two species of Mesochaetopterus (Annelida: Polychaeta: Chaetopteridae) based on collections during 2001–2007 and observations from the Galapagos Islands, Ecuador. Chaetopterus galapagensis sp. nov. is a large (ca. 18 cm long) worm that inhabits a U-shaped tube in soft sand substrates. It is characterized by 12 – 14 chaetigers in the anterior region and 7–8 teeth on uncini of region A neuropodia. Chaetopterus charlesdarwinii sp. nov. is of intermediate size (2 – 4.5 cm long) with 9 anterior region chaetigers and a characteristic brown band on the lateral side of the ventral shield and posterior side of anterior region notopodia. It inhabits irregularly curved tubes cemented to the underside of rocks. Worms may occur singly or aggregated, with up to 10 worms in a cluster. Chaetopterus aduncus sp. nov. is 8–10 cm in length, and is characterized by 10 – 11 anterior region chaetigers, characteristic J-shaped tube with one blind end, and prom...

Phyllochaetopterus lauensis n. sp., a new species of Chaetopteridae, is described from material collected by the DSV Jason II from the vicinity of hydrothermal vents in the Lau Basin, western Pacific Ocean. The new species is characterized by the coloration and patterning of the ventral shield of the anterior region (region A), the presence of one large cutting chaeta on each parapodium of the fourth chaetiger (A4), the shape of these A4 cutting chaetae (with a pear-shaped head), and presence of two middle-region (region B) chaetigers with foliose notopodia. The new species is very similar to some Spiochaetopterus species, but belongs in Phyllochaetopterus based on its possession of a pair of anterior ‘antennae’, which are in fact cirri of chaetiger one with internal chaetae. The new species is compared to other Phyllochaetopterus species, particularly from the Pacific, and we provide a table for all species currently referred to the genus.

Zhang, Yanjie, Rouse, Greg W., Qiu, Jian-Wen (2015): A new species of Mesochaetopterus (Annelida, Chaetopteridae) from Hong Kong, with comments on the phylogeny of the family. Zootaxa 3974 (4): 495-506, DOI: http://dx.doi.org/10.11646/zootaxa.3974.4.2

Phyllochaetopterus socialis Clapar��de, 1870 Type locality. Gulf of Naples, Italy. Records. Lizard Island: Chinamans Head (14 �� 40 ���S 145 �� 27 ���E) AM W. 40253; Lagoon drop off (14 �� 42 ���S 145 �� 28 ���E) AM W. 40255. Comments. This unpublished record needs careful checking given its type locality., Published as part of Ribas, Julia & Hutchings, Pat, 2015, Lizard Island Polychaete Workshop: sampling sites and a checklist of polychaetes, pp. 7-34 in Zootaxa 4019 (1) on page 22, DOI: 10.11646/zootaxa.4019.1.4, http://zenodo.org/record/289472, {"references":["Claparede, E. (1870) Les Annelides Chetopodes du Golfe de Naples. Second partie. Memoires de la Societe de Physique et d'Histoire Naturelle de Geneve, 20 (1), 1 - 225."]}

Genus Chaetopterus Cuvier, 1830 Records. Lizard Island: Lagoon (14 �� 40 ���S 145 �� 27 ���E) AM W. 40731; Chinamans Head (14 �� 36 ���S 145 �� 38 ���E) AM W. 40734; (14 �� 40 ���S 145 �� 27 ���E) AM W. 40730, AM W. 40732; (14 �� 40 ���S 145 �� 28 ���E) AM W. 40733; Crystal Beach (14 �� 40 ���S 145 �� 28 ���E) AM W. 40297; between Bird Islet and South Island (14 �� 40 ���S 145 �� 28 ���E) AM W. 40728, AM W. 40729. Outer Barrier: Yonge Reef (14 �� 36 ��� S 145 �� 37 ��� E) several records. Comments. Obtaining complete specimens of this group is always problematical., Published as part of Ribas, Julia & Hutchings, Pat, 2015, Lizard Island Polychaete Workshop: sampling sites and a checklist of polychaetes, pp. 7-34 in Zootaxa 4019 (1) on pages 21-22, DOI: 10.11646/zootaxa.4019.1.4, http://zenodo.org/record/289472

Genus Chaetopterus Cuvier, 1827 Chaetopterus variopedatus (Reiner, 1804) DISTRIBUTION: NA, CA, SA. LITERATURE RECORDS: Grube 1861; Lorenz 1863; Grube 1864; Stossich 1876, 1883; Carus 1884; Graeffe 1905; Zimmermann 1907; Vatova 1928, 1931a; Fauvel 1934; Vatova 1935, 1943; Gamulin-Brida et al. 1968; Bellan 1969; Banse 1970; Zavodnik 1971; Katzmann 1972; Marcuzzi 1972; Matja��ić & ��tirn 1975; Zavodnik et al. 1978; Vaccarella et al. 1981; Amoureux 1983 c; Fassari 1983; Požar-Domac 1983; Stjepčević et al. 1984; Gillet 1986; Požar-Domac 1986; Aleffi et al. 1988; Gherardi et al. 1993; Požar-Domac 1994; Zahtila 1995, 1997; Gabriele et al. 1999; Zavodnik & Kovačić 2000; Kollmann & Stachowitsch 2001; Aleffi et al. 2003; Solis-Weiss et al. 2004; Aleffi et al. 2005; Solis-Weiss et al. 2007; Castelli et al. 2008. NEW RECORDS: BM 52, BM 53, BM 54. OTHER REPORTED NAMES: Chaetopterus pergamentaceus Cuvier, 1830., Published as part of Mikac, Barbara, 2015, A sea of worms: polychaete checklist of the Adriatic Sea, pp. 1-172 in Zootaxa 3943 (1) on pages 23-24, DOI: 10.11646/zootaxa.3943.1.1, http://zenodo.org/record/244663, {"references":["Grube, A. E. (1861) Ein Ausflug nach Triest und dem Quarnero. Beitrage zur Kenntniss der Thierwelt dieses Gebietes. Berlin, Nicolaische Verlagsbuchhandlung, 175 pp.","Lorenz, J. R. (1863) Physicalische Verhaltnisse und Vertheilung der Organismn im Quarnerischen Golfe. Verlag der Kaiserliche Akademie der Wissenschaften, Wien, 379 pp.","Grube, E. (1864) Die Insel Lussin und ihre Meeresfauna. Verlag Ferdinand Hirt, Breslau, 113 pp.","Stossich, A. (1876) Breve sunto sulle produzioni marine del Golfo di Trieste. Bollettino della Societa adriatica di scienze naturali in Trieste, 2, 349 - 371.","Stossich, M. (1883) Prospeto della fauna del Mare Adriatico. IV Vermes. 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(1972) Le collezioni dell'ex Istituto di Biologia marina di Rovigno conservate presso la stazione Idrobiologica di Chioggia. Atti e Memorie dell'Accademia Patavina di Scienze Lettere ed Arti, 84 (2), 169 - 219.","Matjasic, J. & Stirn, J. (1975) Flora in favna Severnega Jadrana 1. Slovenska akademija znanosti in umetnosti Ljubljana, 54 pp.","Vaccarella, R., Pastorelli, A. M. & De Zio, V. (1981) Metodologie di prelievo: popolamenti a Polycheti in \" mattes \" di posidonia. Thalassia Salentina, 11, 1 - 13.","Amoureux, L. (1983 c) Annelides Polychetes de l'Adriatique. Thalassia Jugoslavica, 19, 15 - 21.","Fassari, G. (1983) Policheti e molluschi delle Bocche del Cattaro (Jugoslavia). Animalia, 10 (1 / 3), 41 - 46.","Pozar-Domac, A. (1983) Polychaeta u bentoskim biocenozama juznog Jadrana. Studia Marina, 13 - 14, 292 - 311.","Stjepcevic, J., Parenzan, P., Mandic, S., Stjepcevic, B. (1984) Kvalitativno - kvantitativna istrazivanja polychaeta unutrasnjeg dijela Bokokotorskog zaliva. 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