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Este artículo contiene 31 páginas, 19 figuras, 3 tablas., The morphological reexamination of specimens previously identified as Laonice bahusiensis Söderström, 1920 from North European and Mediterranean collections, supported by the molecular analysis of freshly collected material, enabled the recognition of four different species in the region: the genuine L. bahusiensis, L. irinae n. sp. from North European waters, and L. grimaldii n. sp. and L. mediterranea n. sp. from the Mediterranean Sea. The morphology of these species is described and illustrated, and their distributions are clarified based on old and new materials. A key for their identification is also provided. The Bayesian analysis of the COI sequences (483 bp) showed that these four species form a clade, namely the L. bahusiensis species complex, morphologically characterized by the continuous dorsal crests on postbranchiate chaetigers in the adults. The genetic p-distances between the species of the complex ranged from 13.27% to 17.99%, while the intraspecific variability ranged from 0.6% to 1.57%. Together with the sister species Laonice cirrata (Sars, 1851), the L. bahusiensis complex formed the Laonice (Laonice) clade, which is morphologically characterized by the prostomium fused with the anterior peristomial margin. However, the monophyly of the L. bahusiensis complex, as well as that of the clade Laonice (Laonice), needs to be further supported through the analysis of a greater set of genes from a larger number of species.

Seven species of Pseudopolydora are described and illustrated from the Arabian Gulf, Kuwait: P. achaeta Radashevsky & Hsieh, 2000, P. antennata (Claparède, 1868), P. arabica Radashevsky & Al-Kandari, 2020, P. auha sp. nov., P. kuwaiti sp. nov., P. melanopalpa sp. nov., and P. multispinosa sp. nov. The morphology of the developed planktonic larvae is described for P. antennata and P. kuwaiti sp. nov. Adults of all species live in tubes in soft sediments, while adults of P. kuwaiti sp. nov. also bore in shells of gastropods and dead corals encrusted by coralline algae. Pseudopolydora antennata and P. arabica form dense settlements up to 50 000 individuals per 1 m2, while other species are comparatively rare. The phylogenetic relationships between the examined species and other Pseudopolydora (18 species in total) were assessed in an analysis of sequence data of four gene fragments: mitochondrial 16S rDNA, nuclear 18S rDNA and 28S rDNA, and Histone 3 (2473 bp in total). Three species complexes are distinguished involving P. antennata, P. diopatra Hsieh, 1992 and P. paucibranchiata (Okuda, 1937). Sets of adult morphological features shared by species of each complex and an identification key to Pseudopolydora species from the Arabian Gulf are provided.

Rhynchospio glandulosa sp. nov. inhabits silty tubes on muddy sand intertidally and in shallow water in the Yellow Sea, Sea of Japan (East Sea), and the Sea of Okhotsk (Korea, China, and Russia). Adults are up to 9 mm long, 1 mm wide for 62 chaetigers, with characteristic groups of glandular cells in the bases of branchiae from chaetiger 7 to chaetigers 14–23. Individuals with 29–40 chaetigers have mature spermatozoa in chaetigers 11–12 or 11–13, while larger worms are simultaneous hermaphrodites with sperm in chaetigers 11–14 and oocytes from chaetiger 16 to chaetigers 22–42. The oocytes are about 120 µm in diameter, with thin and smooth envelopes. The spermatozoa have a small subspherical acrosome about 1 µm long, a tusk-like nucleus 3–4 µm long, small midpiece with subspherical mitochondria, and a flagellum 45–47 µm long. Early larvae develop on the parent’s dorsum from chaetigers 21–27 to chaetigers 30–36, where they are loosely held by flat branchiae and long dorsal capillaries. After utilizing internal egg yolk, the 4-chaetiger larvae 250–280 µm long escape from the parent and continue its development in sea water, feeding on the plankton. About 2 weeks after hatching, the 11-chaetiger larvae 550–570 µm long get ready for settlement and metamorphosis. Rhynchospio glandulosa sp. nov. is one of the seven Rhynchospio species (12 species described so far) known as simultaneous hermaphrodites and one of the three species known to brood their larvae on the parent’s dorsum. The arrangement of male segments and sperm morphology are suggested as important taxonomic characters for the identification of Rhynchospio species. Feeding mechanism of the planktotrophic Spionidae larvae is briefly discussed.

Four Pseudopolydora Czerniavsky, 1881 species from European and adjacent waters are distinguished and a key to their identification is provided. Pseudopolydora antennata (Claparede, 1868) is redescribed based on material from the type locality, Gulf of Naples, Italy. Pseudopolydora pulchra (Carazzi, 1893) (type locality in the Gulf of Naples) is also redescribed based on material from Italy. Most previous records of the Asian P. paucibranchiata (Okuda, 1937) from North European waters are herein referred to a new species, P. nordica sp. nov. The latter differs from P. paucibranchiata by the absence of an occipital antenna on the prostomium and yellow ramified chromatophores on palps. Native to the Northwest Pacific, P. paucibranchiata was first recorded in European waters from the Tyrrhenian Sea, Lazio, Italy, in 1978. Since then, the species has spread widely in the Mediterranean and in 2015 was first recorded from northern Europe in the Netherlands.

The Asian Pacific spionid polychaete worm Pseudopolydora paucibranchiata (Okuda, 1937) has been repeatedly reported from the Arabian Gulf and the Arabian Sea. Our recent molecular study showed that the Pacific and the Arabian populations of these worms are not conspecific. Here we describe adult, gamete, and larval morphology of worms from the Arabian Gulf, Kuwait, as the new species Pseudopolydora arabica sp. nov. Adults are characterized by the presence of intense yellow pigment on the prostomium, the dorsal side of the anterior chaetigers, and up to 50 ramified yellow chromatophores on each palp. Males produce thread-like wavy spermatophores about 10 μm in diameter and up to 2 mm long. Females store sperm in seminal receptacles on the dorsal side of fertile chaetigers and lay up to 1500 eggs into 35 capsules joined to each other in a string; each is attached by one stalk to the inner wall of the tube. Eggs are 100−103 μm in diameter, with smooth and thin envelopes, which develop into 3-chaetiger larvae inside the capsules. Hatched larvae are planktotrophic and settle and metamorphose at about 17 chaetigers. Adults inhabit silty tubes in soft sediments forming aggregations of up to 50,000 individuals per 1 m2.

Spiophanes bombyx (Claparède, 1870) from the Gulf of Naples, Tyrrhenian Sea, Italy, was the first described Spiophanes with fronto-lateral horns on the prostomium. It was also considered the only horned species occurring in European waters. Our sequence data of five gene fragments suggest the presence of two horned sibling Spiophanes species in northern Europe: S. cf. bombyx in the North and the Norwegian seas, and S. cf. convexus in Brittany, northern France, and Bay of Biscay, northern Spain. Spiophanes cf. bombyx worms are genetically close to a single examined specimen of S. bombyx from Venice Lagoon, Italy but their conspecificity should be verified by further study. Our sequence data show that horned Spiophanes from the North Pacific are genetically distant from horned European species, and that S. uschakowi Zachs, 1933, originally described from the Sea of Japan (East Sea) is a valid species. The data also suggest the presence of two horned sibling Spiophanes species in the North East Pacific: S. hakaiensis Radashevsky & Pankova, n. sp. distributed from Alaska south to about Point Conception, and S. norrisi Meißner & Blank, 2009, distributed from San Francisco Bay south to Baja California Sur, Mexico. Spiophanes from South America, morphologically similar to S. norrisi, are suggested to belong to a new species. Molecular data also suggest the presence of two sibling species among the worms from northern Europe identified by morphology as S. kroyeri Grube, 1860. Worms from the Barents Sea and northern part of the North Sea are tentatively referred to as S. cf. kroyeri; worms from the northern and central parts of the North Sea and from the Bay of Biscay, northern Spain, are tentatively referred to as S. cf. cirrata M. Sars in G.O. Sars, 1872. Sequence data also show that S. duplex from California is genetically different from morphologically similar worms from South America. The South American worms are referred to resurrected S. soederstroemi Hartman, 1953 which was originally described from off Rio Grande do Sul, Brazil, and then considered as a junior synonym of S. duplex. Analysis of divergence times of Spiophanes lineages suggested that the origin of the most recent common ancestor of horned Spiophanes with metameric nuchal organs was around 11.1 mya (95% HPD: 5.1–19.0 mya) and that the divergence of the North Atlantic and North Pacific lineages was around 7.9 mya (95% HPD: 4.1–13.3 mya). The North Atlantic lineage was estimated to have diverged 4.8 mya (95% HPD: 2.2–8.6 mya), resulting in the origin of S. cf. bombyx and S. cf. convexus. The North Pacific lineage was estimated to have diverged first by the isolation and speciation of S. norrisi 1.7 mya (95% HPD: 2.3–1.0 mya), and then by the isolation and speciation of S. uschakowi and S. hakaiensis n. sp. 1.3 mya (95% HPD: 2.0–0.7 mya). The estimates place the divergences soon after maximum glacial period in the North Pacific (2.4–3.0 mya).

Polychaetes of the spionid genus Trochochaeta occur mainly in the northern hemisphere, including North and Central America. In South America, they have been reported only from the northeast region of Brazil – Sergipe and Paraíba – despite numerous biological investigations around the continent. In 2006, a dense population (up to 7000 individuals per square meter) of Trochochaeta was discovered in the estuary of Santos, São Paulo, Brazil, hosting the busiest container sea port in Latin America, and in 2008, one Trochochaeta specimen was found in Camamu Bay, Bahia. We identify these worms as Trochochaeta japonica Imajima, 1989 and describe and illustrate their morphology. This is the first record of the species from outside of its type locality in Honshu, Japan. It might have been introduced to the estuary of Santos as larvae in ballast water of ocean-going vessels. We review the systematics of Trochochaeta and provide an identification key to 12 currently recognized species.

Spiophanes uschakowi is a common polychaete living in tubes in sandy sediments in shallow waters of the Sea of Japan. Females and males release their gametes into the water where fertilization and holopelagic, planktotrophic larval development occur. In females, oogenesis is intraovarian: vitellogenesis occurs when the oocytes grow in paired ovaries attached to genital blood vessels in fertile segments. The developed oocytes are accumulated in the coelomic cavity prior to spawning. The newly released oocytes are lentiform, 185–200 μm in diameter, with honey-combed envelopes 5–7 μm thick. Each oocyte has 41–49 cortical alveoli regularly arranged in a peripheral circle, a nucleus 80–83 μm in diameter, and a single nucleolus about 30 μm in diameter. In males, spermatogonia proliferate in testes and the rest of spermatogenesis occurs in the coelomic cavity. During spermiogenesis, the acrosomal vesicle migrates from the posterior to the anterior part of the spermatid. The spermatozoa are ect-aquasperm with a plate-like acrosome 0.58 ± 0.06 μm thick and 2.14 ± 0.13 μm in diameter, barrel-shaped nucleus 2.23 ± 0.13 μm long and 3.18 ± 0.13 μm in diameter, short midpiece 0.93 ± 0.09 μm long with five spherical mitochondria, two centrioles and one small lipid droplet, and a flagellum 62–63 μm long with 9 × 2 + 2 organization of microtubules. The acrosome is a complex heterogeneous structure with 4–6 subspherical apical bodies, and numerous small branched basal cisternae. The anterior end of the nucleus is truncate, while its posterior end has wide shallow depressions accommodating the mitochondria. The centrioles are situated in the center of the midpiece between mitochondria and oriented obliquely to each other. The structure of the gametes of broadcast-spawning spionids is reviewed and the roles of surface granules in species-specific attraction of sperm toward eggs by releasing chemical signals (sperm chemotaxis), and cortical alveoli as a place of penetration of spermatozoa into oocytes (micropyle) are suggested. The lentiform oocytes of Spiophanes spp. are unique among Spionidae by their shape, while spermatozoa are unique by their plate-like acrosomes.

Spermatogenesis and the structure of the spermatozoa of two spionid polychaetes Dipolydora bidentata and Dipolydora carunculata are described by light and transmission electron microscopy. Both species are gonochoristic borers in shells of various molluscs. Proliferation of spermatogonia occurs in paired testes regularly arranged in fertile segments, and the rest of spermatogenesis occurs in the coelomic cavity. Early spermatogenesis occurs quite similarly in the two species but results in formation of tetrads of interconnected spermatids in D. bidentata and octads of spermatids in D. carunculata. Three consecutive stages of spermiogenesis are recognized according to the condensation of chromatin in nucleus: (1) early spermatids with heterogeneous, partly clumped chromatin, (2) middle spermatids with homogeneous, coarsely granular chromatin, and (3) late spermatids with homogeneous fibrillar chromatin. Moreover, late stage of spermatids is further classified into two stages, I and II, according to the position of the acrosome and shape of the nucleus. In late spermatids I, the acrosome is situated in the anterior invagination of the funnel-shaped to oval nucleus, whereas in late spermatids II the acrosome is situated on top of the elongated nucleus. Ultrastructural composition of cells at each stage of spermatogenesis is described and illustrated. The possible process of morphogenesis of organelles during spermato- and spermiogenesis is reconstructed for both species. The proacrosomal vesicle first appears in early spermatids near the Golgi complex and then migrates anteriorly; in the middle spermatids, the acrosome comes to lie in a deep anterior nuclear fossa. In late spermatids I, this fossa evaginates and a posterior fossa develops in the nucleus housing basal body and the anterior part of the axoneme. In late spermatids II, the mitochondria elongate and probably reduce in number due to fusion of some of them. The mature spermatozoa in both species are introsperm with the conical acrosome, subacrosomal plate, long nucleus with short posterior fossa, long midpiece with elongated mitochondria, and long flagellum with 9 × 2 + 2 organization of microtubules. Numerous flat rounded platelets with putative glycogen are present throughout most part of the nucleus and the midpiece. The process of spermatogenesis in D. bidentata and D. carunculata is similar to that in other Dipolydora, Polydora and Pseudopolydora species. Spermatozoa in these polydorin spionids have similar composition and differ mainly in size of the nucleus and the midpiece. Elongated spermatozoa are adapted for transfer in spermatophores and an internal fertilization which is characteristic for brooding species. Diversely modified spermatozoa among spionids may be signs of the diversity of fertilization biology within the Spionidae. The exact places where fertilization occurs in brooding spionids however remains unknown.

Rhynchospio glutaea (Ehlers, 1897), Rhynchospio arenincola Hartman, 1936 and Rhynchospio arenincola asiatica Chlebovitsch, 1959, originally described from Strait of Magellan, California, and South Kurile Islands respectively, appear similar to each other in adult morphology. These species and subspecies have been considered by some authors as subjective synonyms and are here referred to as members of the R. glutaea complex. Sequence data of four gene fragments (2465 bp in total) of the mitochondrial 16S rDNA, nuclear 18S and 28S rDNA, and Histone 3 have shown that R. glutaea complex individuals from the South West Atlantic (Argentina), North East Pacific (British Columbia and Oregon) and North West Pacific (South Korea) were genetically distant and not conspecific. These data also indicate that R. arenincola from North America and R. aff. asiatica from South Korea are more closely related to each other, and both are closer to R. glutaea from South America than to R. nhatrangi from Vietnam: nhatrangi (glut...

A checklist of the polychaete fauna collected from the intertidal coastal zone along the northern part of the Arabian Gulf in Kuwait is presented. Samples were collected from 42 transects, including mainland areas and seven islands, during late autumn and winter seasons from 2013 to 2016. In total, 172 polychaete species from 46 families were identified, 19 are new records to the Arabian Gulf and 17 to the Arabian Region. The most abundant species belonged to the family Spionidae, followed by Nereididae, and Serpulidae. The list represents a regional taxonomical work which can provide baseline data for future studies and a useful basis for future conservation plans relevant to this region.

Reproductive health of the common cupped oyster Crassostrea angulata cultivated in Taiwan was estimated through histological examination and semiquantitative analysis of their gonads. Oysters were collected in 4 aquaculture sites along the western coast of Taiwan (Hsiangshan, Chiku, Beimen, and Putai), where the major sources of industrial pollution are located, and off Penghu Island in the southern part of the Taiwan Strait, a comparatively clean resort area. The oysters from Hsiangshan had the lowest gonad maturity index (GMI) and the highest index of pathological alterations (IPA; P < 0.001); greater numbers of oysters with undifferentiated gonads (30%) and a green mantle (66.7%) were also present here. Most prominent gonad pathologies were atresia of oocytes and hemocytic infiltration of gonadal tissue. Oysters from Penghu had the highest GMI and the lowest IPA, whereas oysters from Chiku, Beimen, and Putai had intermediate values. Soft tissues of oysters from Hsiangshan contained 3,761.0 ± 1,201.0 µg/g dry weight Cu, 3,761.0 ± 1,201.0 µg/g Zn, and 1.5 ± 0.06 µg/g Cd, which is about 17 times, 3 times, and 1.5 times greater than the corresponding metal concentrations in the tissues of oysters from Penghu. Gametogenesis impairment in oysters cultivated in Taiwan are likely caused by environmental pollution.

The spionid polychaete Polydora hoplura Claparede, 1868, is a harmful shell-borer accidentally transported with objects of aquaculture across the world. It was originally described from the Gulf of Naples, Italy, and later widely reported from European waters, South Africa, the Arabian Gulf, New Zealand, Australia and Tasmania. Here, for the first time, we describe adults and larvae of P. hoplura from Atlantic South America (Brazil), and report this species from Pacific North America (California, USA). We also examined material from Italy, New Zealand, Australia, Chile and Japan, and treat Polydora uncinata Sato-Okoshi, 1998, from Japan, as a junior synonym of P. hoplura. Consequently, we report P. hoplura for the first time in the Asian Pacific, Japan and South Korea, and in Pacific South America (Chile). The new records of P. hoplura from the American continents are cause for concern. The spread of this non-indigenous species may have negative impacts on the farm cultivation of oysters and abalone.

Free crawling was an original life style, and the ability to build tubes and bore into shells evolved independently in various annelids and more than once within the family Spionidae. Absence of morphological differences between the shell-boring (SB) and tube-dwelling (TD) spionid worms and the innate ability of borers to build tubes raised a question whether the mode of life is fixed or flexible. Sequence data of three gene fragments of the mitochondrial 16S rDNA and nuclear 18S and 28S rDNA (in total 1,677 bp) have shown that SB and TD individuals of Dipolydora carunculata from the Sea of Japan were genetically identical, whereas those of Polydora triglanda from Taiwan were genetically distant and not conspecific. These data indicate that some species are constrained to a certain mode of life, while others are flexible and individuals can be either SB or TD depending on the place of settlement in the end of their larval development.

Rhynchospio Hartman, 1936 is a small group of spionid polychaetes currently comprising ten described species distributed mainly in the Pacific. Five species examined to date are hermaphrodites producing spermatozoa with long nuclei, oocytes with thin and smooth envelopes, and dorsally brooding their offspring. Since our first molecular analysis of four Rhynchospio species, we have collected additional material from Northern Territory, Australia, and Oregon, USA. Herein, we describe the gamete and adult morphology of the newly collected material and use molecular analyses to provide new insight on the phylogenetic relationships of six Rhynchospio species. Adults of R. cf. foliosa from Oregon are hermaphrodites, but in contrast to other Rhynchospio, they produce spermatozoa with short nuclei (ect-aquasperm), oocytes with thick vesiculate envelopes, and likely have a holopelagic larval development. Analysis of four gene fragments, comprising mitochondrial 16S rDNA, and nuclear 18S, 28S rDNA, and Histone 3 (2516 bp in total) showed Rhynchospio to be a monophyletic group, with R. cf. foliosa being a distant sister to the five other species. Rhynchospio cf. foliosa was closer to M. arctia having ect-aquasperm and vesiculate thick-envelop oocytes (p = 14.40%) than to Spioninae members B. proboscidea and P. elegans, having introsperm and oocytes with thin and smooth envelopes (p = 15.39 and 16.54%, respectively). We hypothesize that brooding might have evolved from free-spawning inside the Rhynchospio clade, but this hypothesis should be tested in a future analysis.

Adults of Aonides oxycephala, common inhabitants of shallow boreal waters in the Atlantic and Pacific Oceans, release gametes into the water where fertilization and lecithotrophic larval development occur. During spermiogenesis, the acrosomal vesicle migrates from the posterior to the anterior end of the spermatid and the number of mitochondria reduces from six in early spermatids to four in mature spermatozoa. Each spermatozoon has an ovoid head with the acrosome 1.4 ± 0.1 µm long and 1.6 ± 0.1 µm wide and the nucleus 1.7 ± 0.1 µm long and 2.3 ± 0.1 µm in diameter, four spherical mitochondria, two centrioles oriented perpendicular to each other, putative glycogen in the shape of dense granules in the midpiece, and a flagellum with 9 × 2 + 2 organization of microtubules. The acrosome is a complex heterogeneous structure with five ordered layers of different electron densities, lying in a shallow depression on the anterior end of the nucleus. The nucleus is barrel-shaped (truncated ovoid) with the centriol...

Reunov, A.A., Yurchenko, O.V., Alexandrova, Y.N. and Radashevsky, V.I. 2009. Spermatogenesis in Boccardiella hamata (Polychaeta: Spionidae) from the Sea of Japan: sperm formation mechanisms as characteristics for future taxonomic revision. —Acta Zoologica (Stockholm) 91: 477–456. To characterize novel features that will be useful in the discussion and validation of the spionid polychaete Boccardiella hamata from the Sea of Japan, the successive stages of spermatogenesis were described and illustrated. Spermatogonia, spermatocytes and early spermatids are aflagellar cells that develop synchronously in clusters united by a cytophore. At the middle spermatid stage, the clusters undergo disintegration and spermatids produce flagella and float separately in coelomic fluid as they transform into sperm. Spermatozoa are filiform. The ring-shaped storage platelets are located along the anterior nuclear area. The nucleus is cupped by a conical acrosome. A nuclear plate is present between the acrosome and nucleus. The nucleus is a cylinder with the implantation fossa throughout its length and with the anterior part of the flagellum inside the fossa. There is only one centriole, serving as a basal body of the flagellum, situated in close vicinity of the acrosomal area. A collar of four mitochondria is located under the nuclear base. The ultrastructure of B. hamata spermatozoa from the Sea of Japan appears to be close to that of B. hamata from Florida described by Rice (Microscopic Anatomy of Invertebrates, Wiley-Liss, Inc., New York, 1992), suggesting species identity of the samples from the two regions. However, more detailed study of Florida’s B. hamata sperm is required for a reliable conclusion concerning the similarity of these two polychaetes. In addition to sperm structure, features such as the cytophore-assigned pattern of spermatogenic cell development, the synchronous pattern of cell divisions, the non-flagellate early spermatogenic stages, and the vesicle amalgamation that drives meiotic cell cytokinesis and spermatid diorthosis will likely be useful in future testing of the validity of B. hamata and sibling species throughout the world.

The purpose of this application, under Articles 23.9.3, 75.5 and 81.1 of the Code, is to conserve the much-used specific name Boccardia proboscidea Hartman, 1940 for a widely dispersed mudworm (family spionidae) from California. It is proposed that the name Boccardia proboscidea be given precedence over its rarely used senior subjective synonym Polydora californica Treadwell, 1914, and that previous type fixations for Boccardia proboscidea Hartman, 1940 be set aside and one specimen be designated as neotype for this species. It is also proposed that an untypified name Spio californica Fewkes, 1889 be suppressed to avoid unnecessary confusion.

Laonice species from South and Central America are reviewed based on museum collections and new material collected in southern Brazil. An identification key is provided to 10 species including three previously described species, L. antarcticae Hartman, 1953, L. weddellia Hartman, 1978, L. branchiata Nonato, Bolívar & Lana, 1986, and three species represented by poor material, insufficient for final taxonomic diagnosis. Four new species, L. petersenae sp. nov., L. aperata sp. nov., L. parvabranchiata sp. nov., and L. pinnulata sp. nov. are described and illustrated. Earlier records of L. cirrata (M. Sars, 1851) from South America are not confirmed. The loss of neuropodial sabre chaetae and hooks until a certain size in terms of numbers of adult chaetigers is here used for the first time as a specific character with Laonice species.

Adults ofPseudopolydora rosebelaesp. nov. inhabit silty tubes on muddy bottoms in shallow water in southern Brazil, states of São Paulo and Rio de Janeiro. They are rare and extremely delicate, attaining 20 mm long for 55 chaetigers. The worms are distinctive by their colourful yellow and black pigmentation on the anterior part of body and palps, prominent transverse hood on the dorsal anterior edge of chaetiger 3, and lack of coloured respiratory pigment in blood. Of 12 examined individuals, all were females. Oogenesis is intraovarian; oocytes develop from chaetigers 14–15 to chaetigers 24–36. Recently laid oocytes were about 150 μm in diameter, with embryos and developing larvae found in capsules inside female tubes in March–June. Broods comprised up to 23 capsules with 400 propagules. Capsules were joined to each other in a string and each attached by a single thin stalk to the inner wall of the tube. Larvae hatched at the 4-chaetiger stage and fed on plankton. Pelagic larvae are unique amongPseudopolydorain having large ramified mid-dorsal melanophores from chaetiger 3 onwards. Competent larvae are able to settle and metamorphose at the 15-chaetiger stage, but can remain planktonic up to 18 chaetigers. They have one pair of unpigmented ocelli and three pairs of black eyes in the prostomium, unpaired ramified mid-dorsal melanophores on chaetiger 1 and on the pygidium, ramified lateral melanophores on chaetigers 5–10, prominent yellow chromatophores in the prostomium, peristomium, on dorsal and ventral sides of chaetigers and in the pygidium. Branchiae are present on chaetigers 7–10, and gastrotrochs are arranged on chaetigers 3, 5, 7 and 12. Provisional serrated bristles are present in all notopodia, and hooks are present in neuropodia from chaetiger 8 onwards. Two pairs of provisional protonephridia are present in chaetigers 1 and 2, and adult metanephridia are present from chaetiger 4.

Pygospio elegans Claparède, 1863, the type species of the genus Pygospio, was originally described from Normandy, France, and later widely reported from boreal waters in the northern hemisphere. Sequence data of four gene fragments (2576 bp in total) of the mitochondrial 16S rDNA, nuclear 18S and 28S rDNA, and Histone 3 have shown that individuals from California and Oregon, USA, Scotland and the White Sea, Russia were genetically similar (the average p-distances for the combined data between the four groups ranged from 0.04 to 0.16%, average p = 0.1%). These individuals are considered to be conspecific and the amphiboreal distribution of P. elegans is here confirmed. Adult morphology of the species is briefly described and illustrated. The molecular analysis revealed two genetically distant populations, Pygospio sp. 1 from the Sea of Okhotsk and Pygospio sp. 2 from Oregon. The morphological differences and high average genetic p-distances for the combined data (ranging from 3.06 to 3.18%, average p = 3.12%) between Pygospio sp. 2 and P. elegans suggest the presence of an undescribed Pygospio species co-occurring with P. elegans in Oregon. High morphological similarity and moderate genetic p-distances for the combined data (ranging from 1 to 1.11%, average p = 1.07%) between Pygospio sp. 1 and P. elegans indicate a comparatively recent genetic divergence of the Pygospio population in the Sea of Okhotsk. Taking into account the high genetic similarity of the remote European and North American populations of P. elegans and medial location of the Pygospio sp. 1 population, we suggest the latter to belong to a separate species. However, this conclusion should be verified in further studies on the morphology, reproductive biology and genetics of this population. The present findings show the need to re-examine Pygospio from the Asian Pacific and elsewhere that have been identified as P. elegans.

Adults of a new spionid polychaete, Rhynchospio nhatrangi, inhabit sandy tubes on muddy sand intertidal flats in an estuary of Nha Trang Bay, southern Vietnam. The worms are up to 8 mm long and 0.5 mm wide for 55 chaetigers. They are unique among spionids in the changes in the arrangement of hooks during ontogenesis: first development of tridentate hooks in neuropodia from chaetiger 10, later loss of hooks in chaetiger 10, and replacement of tridentate hooks by heavy unidentate hooks in neuropodia of chaetigers 11–14. Adults are simultaneous hermaphrodites having sperm in chaetigers 11–14 and oocytes from chaetiger 15 to 23–33. Spermatozoa are introsperm, about 300 µm long. Oocytes are about 120 µm in diameter, with a thin and smooth envelope. Fertilization and early larval development occur in a hatchery formed by elongated dorsal capillaries on the posterior chaetigers. Larvae escape from the hatchery probably when they have developed four chaetigers and then continue development in seawater, feeding on...

Nineteen species in seven genera of spionid polychaetes are described and illustrated based on new material collected from the intertidal and shallow waters around the Lizard Island Group, northern Great Barrier Reef. Only one of these species had been previously reported from the Reef. Six species are described as new to science, and the taxonomy of seven species should be clarified in the future. Prionospio sensu lato is the most diverse group with 11 species identified in the present study. One species is identified in each of the genera Dipolydora, Polydorella, Rhynchospio and Tripolydora, and two species are identified in each of the genera Aonides and Pseudopolydora. The fauna of spionid polychaetes of the Great Barrier Reef seems to be more diverse than previously described and more species are expected to be found in the future. An identification key is provided to 16 genera of Spionidae reported from or likely to be found on the Great Barrier Reef.

Two sympatric species earlier differentiated by means of starch gel electrophoresis within Polydora cf. ciliata from the Sea of Japan are here identified and their adult and gamete morphology are described and illustrated. One species bores into various shells and coralline algae while the other bores only into gastropod shells occupied by hermit crabs. Both species have the prostomium anteriorly incised to rounded, 0–4 eyes, the caruncle extending to the end of chaetiger 2, heavy falcate spines of chaetiger 5 with a lateral tooth, branchiae beginning on chaetiger 7, and the pygidium disc-like to cup-shaped with a dorsal gap to only an incision. Males of the two species differ in aggregations of spermatids. The more opportunistic borer, which occurs in a greater number of hosts, always has 8-cell-aggregations of spermatids. These worms are here referred to as P. calcarea. The other species, in which spermatids are always interconnected in tetrads, is here described as a new one, P. manchenkoi sp. nov. The two species also differ in that prominent brownish-yellow pigment appears on the posterior segments after fixation in formaldehyde in P. manchenkoi sp. nov. but not in P. calcarea. It is suggested that spermatid aggregates and spermatozoan morphology be included in future polychaete descriptions when possible.

Prionospio patagonica inhabits temporary silty tubes intertidally and shallow subtidally in brackish water estuarine environments in southern Chile. The species is gonochoristic with the female:male ratio being close to 2:1. Females and males release gametes into water. Pelagic planktotrophic larvae were caught in the plankton in the River Valdivia estuary in October–November and in March. Development of the adult morphology is described and illustrated beginning from the 2-chaetiger larval stage. One pair of lateral eyes first appears in the early larva, and shortly after that the right median eye develops. The left median eye appears after settlement, in juveniles with 10–11 segments. Developed 6-segment larvae have three dark red eyes, short palps of equal length, no nototrochs, one pair of small cells with grasping cilia on the pygidium, a small ciliated pit, gastrotrochs on segments 2–6, long serrated bristles in notopodia, adult capillaries in noto- and neuropodia on segments 2–5, single hooks in both rami on segment 6, and one pair of provisional papillae on the pygidium. A ventral buccal bulb is present below the short oesophagus and two pairs of provisional protonephridia are present in segments 1 and 2. The wall of the anterior part of the midgut has a characteristic brown pigment. The 6-segment larvae, about 400 μm long, settle and undergo gradual metamorphosis. In adults, hooks are gradually lost from noto- and neuropodia but sabre chaetae appear from segment 7 and retain their anterior position as growth proceeds. Up to 14 pairs of cirriform branchiae develop from segment 2, and three adult cirri appear on the pygidium. The afferent and efferent arms of each branchial blood loop are interconnected by capillary loops. A greenish heart body is present in the main dorsal blood vessel in anterior segments. Up to 21 pairs of metanephridia develop in anterior sterile segments, beginning with segment 4. Transparent gonoducts are present in fertile segments.

The spionid polychaete Polydora rickettsi is primarily a borer in various calcareous substrata in the eastern Pacific. Redescription of the species from the type locality in Mexico is required to better understand its distribution. In Chile, females and males become mature after growth to c. 60 segments. Sex allocation in the population is close to 1:1. Gametes develop along segmental blood vessels in middle segments. Spermatogonia proliferate in temporary testes and the rest of spermatogenesis occurs in the coelomic cavity. On their release through metanephridial segmental organs, longheaded spermatozoa are packed in filiform spermatophores. Females store inactive spermatozoa in paired seminal receptacles on the dorsal side of fertile segments. Oogenesis is mostly intraovarian. Females deposit up to 4150 eggs into 65 capsules which are joined to each other in a string. Each egg capsule is attached by two stalks to the inner wall of the burrow and contains up to 65 eggs c. 95 μm in diameter. Most...

A Dipolydora species (Polychaeta: Spionidae) was found in mud tubes attached to the larger tubes of the chaetopterid polychaete Chaetopterus cautus in Peter the Great Bay of the Sea of Japan. The worms were close in morphology to D. carunculata, a borer of various calcareous substrata and sponges described earlier from the same area. The chaetopterid-associated tube-building individuals usually differed from shell-boring individuals by the presence of black pigmentation on palps. However, some of them were not pigmented and appeared almost identical to D. carunculata. Isozymes of the tube-building and shell-boring individuals were compared using starch gel electrophoresis. Two of 16 studied isozyme loci proved diagnostic and unequivocally demonstrated the presence of two distinct species. The chaetopterid-associated individuals are described here as a new species, D. melanopalpa. Unbiased Nei's genetic distance between D. melanopalpa and D. carunculata (D=0·949) as well as the level of intraspecific genetic variation in either of them (D. melanopalpa, He=0·206±0·054; D. carunculata, He=0·239±0·044) are high and comparable to those of other electrophoretically studied polydorids. In contrast to other examined polydorids, D. carunculata and D. melanopalpa have the same numbers of expressed isozyme loci.

Chromosome complements of Polydora curiosa Radashevsky, 1994 (Polychaeta: Spionidae) were examined using air-drying method. Regenerating worm tips and gamete-bearing segments were used for the analysis. A diploid chromosome number of 34 was found in well-spread metaphase plates of somatic cells. A pair of sex chromosomes (XY) with the Y considerably larger than the X was found in males. The size and shape of the Y chromosome were individually variable. Sixteen normal bivalents and one large univalent-like bivalent were observed in metaphase I plates of sper-matocytes. The large bivalent is the end-to-end association of heteromorphic sex chromosomes having very low structural homology. As many as 39% of studied spermatocytes of P. curiosa were found to be tetraploid cells. The sex chromosome system described herein is the first case of XY male heterogamety in the Spionidae and only the second one so far documented in the Polychaeta.

A new spionid polychaete species, Polydom neocaeca, is described from intertidal and shallow subtidal areas in Rhode Island on the east coast of North America. Adults bore into shells of living gastropods, gastropod shells occupied by hermit crabs, and bivalve shell fragments. Females deposit 13–24 egg capsules joined in a string from June-November. Each egg capsule is attached by two stalks to the inside wall of the burrow and contains 8–47 eggs, for a mean of 481 eggs per brood. The eggs have an average diameter of 116 μm. Development occurs within the egg capsules until the 3-segment stage at which time planktotrophic larvae are released. A series of adult morphological characters was examined and found to vary extensively in body pigmentation but less so in palp pigmentation, prostomium shape, presence of neurosetae and notosetae of the fifth segment, and caruncle length. Polydora neocaeca belongs to the Polydora ciliata/websteri species group and is characterized by palps crossed by black ba...

Polydora websteri Hartman in Loosanoff & Engle, 1943 (Polychaeta: Spionidae) was proposed as a replacement name for Polydora caeca Webster, 1879, a junior secondary homonym of P. coeca (Orsted, 1843). Comparison of Webster's description with Hartman's material used for her redescription and with recently discovered specimens matching Webster's description, has revealed that Webster and Hartman dealt with two different species. The International Commission on Zoological Nomenclature has been accordingly asked that P. websteri should not be treated as a replacement name for P. caeca Webster, and that a lectotype be designated in accord with accustomed usage. The proposed lectotype for P. websteri Hartman is described in the present study. Polydora websteri is well known as a borer in the shells of oysters and other commercially important molluscs.

Two morphologically indistinguishable but genetically very distinct polychaete species of the family Spionidae are found in the Peter the Great Bay of the Sea of Japan. Both species bore into molluscan shells and occur sympatrically. They are close in morphology to Polydora ciliata (Johnston, 1838) and some other members of the redefined P. ciliata species complex. The systematics of the two species is still under consideration by one of us (V.I.R.). A total of nine enzyme systems comprising 12 isozyme loci were examined in both the species by means of starch gel electrophoresis. Nei's genetic distance between them proved surprisingly high (D= 1.942) being the highest among estimates so far obtained for pairs of polydorid species. The levels of intraspecific genetic variation in both species (Polydora sp. 1, H e= 0.287 ± 0.064; Polydora sp. 2, H e= 0.111 ± 0.045) are comparable to those of other electrophoretically studied polydorids. The problem of taxonomic integrity of cosmopolitan marine invertebrate species is briefly discussed as well as the usefulness of isozymes as species-specific characters suitable for unequivocal discrimination between sibling polydorid species. A list of enzymes characterized by interspecifically variable numbers of expressed isozymes within polydorids is given and recommended for such a discrimination.

Two spionid polychaetes, Polydora cornuta and Streblospio gynobranchiata, were identified in benthic samples collected in the northern Black Sea and adjacent waters. These species have earlier been classified as the worst invaders in soft bottom communities in the Mediterranean Sea. Polydora cornuta had been previously misidentified and widely reported from the Black Sea and the Sea of Azov as P. ciliata, P. ciliata limicola and P. limicola. Streblospio gynobranchiata is a new invader currently extending its distribution into the Mediterranean, Black and Caspian Seas. Morphology, diagnostic characters and biology of the species are discussed and the history of their records in the Mediterranean, Black and Caspian Seas and the Sea of Azov is reviewed.

Rhynchospio Hartman, 1936 is a small group of spionid polychaetes currently comprising ten described species distributed mainly in the Pacific. Five species examined to date are hermaphrodites producing spermatozoa with long nuclei, oocytes with thin and smooth envelopes, and dorsally brooding their offspring. Since our first molecular analysis of four Rhynchospio species, we have collected additional material from Northern Territory, Australia, and Oregon, USA. Herein, we describe the gamete and adult morphology of the newly collected material and use molecular analyses to provide new insight on the phylogenetic relationships of six Rhynchospio species. Adults of R . cf. foliosa from Oregon are hermaphrodites, but in contrast to other Rhynchospio , they produce spermatozoa with short nuclei (ect-aquasperm), oocytes with thick vesiculate envelopes, and likely have a holopelagic larval development. Analysis of four gene fragments, comprising mitochondrial 16S rDNA, and nuclear 18S , 28S rDNA, and Histone 3 (2516 bp in total) showed Rhynchospio to be a monophyletic group, with R. cf. foliosa being a distant sister to the five other species. Rhynchospio cf. foliosa was closer to M. arctia having ect-aquasperm and vesiculate thick-envelop oocytes ( p = 14.40%) than to Spioninae members B. proboscidea and P. elegans , having introsperm and oocytes with thin and smooth envelopes ( p = 15.39 and 16.54%, respectively). We hypothesize that brooding might have evolved from free-spawning inside the Rhynchospio clade, but this hypothesis should be tested in a future analysis.

Polydora vulgaris Mohammad, 1972, a commensal borer of the oysters Pinctada margaritifera and Hyotissa hyotis from the South China Sea, was investigated by means of starch gel electrophoresis. Polydora vulgaris and the allopatric sibling Polydora glycymerica Radashevsky, 1993, a commensal borer of the bivalve Glycymeris yessoensis from the Sea of Japan, were compared with respect to their allozymic variation and number of isozyme loci. Interspecific differences in the number of gene loci coding for three enzymes: alanopine dehydrogenase, glucose-6-phosphate isomerase and l -iditol dehydrogenase were revealed suggesting that we are dealing with two valid species. Two different modes of origin duplicate loci in polydorids are dicussed—polyploidization and regional gene duplication. The use of gene number as a character for discriminating between morphologically indistinguishable allopatric polydorid taxa is outlined.

A new spionid species, Polydora curiosa, from the Kurile Islands and adjacent areas is described. Adults bore into calcareous substrata. Females deposit 13–33 eggs in 7–18 capsules joined in a string, in June-August. Each egg capsule is attached by two stalks to the inside wall of the female's burrow and contains 1–4 eggs. The eggs are rich in yolk and have a diameter of 240–330 µm. Each egg develops into a non-feeding larva. The larvae leave the capsules at about the 20-segment stage and have only a short pelagic life before undergoing settlement and metamorphosis. Modes oflarval nutrition and patterns oflarval development in Polydora and related genera are discussed. Among the lecithotrophic larvae, two groups are recognized according to the yolk position. These are exolecithotrophic (feeding on nurse eggs or smaller larvae) and endolecithotrophic (obtaining their nutrient from the yolk stored in the egg). Distinct morphological differences between the two larval types are considered. Planktotr...

Two sympatric sibling Polydora species, P . cf. ciliata (Johnston) boring into calcareous substrata and P. limicola Annenkova inhabiting mud tubes in fouling on bottoms of ships, were investigated through their allozyme variations by means of starch gel electrophoresis. A survey of 18 enzyme systems comprising 27 loci showed a lack of common alleles at 10 loci: Fdh, Fum, Got-2, Gpi-1, Gpt, Lap, Mdh-1, Mdh-2, Sdh, Sod and duplication of alkaline phosphatase gene in P . cf. ciliata and glucose phosphate isomerase gene in P. limicola . Our genetic data indicate that we have two good congeneric Polydora species distinguishable by their allozyme variation and different in their ecology. The values of Nei's indices of genetic identity and standard genetic distance between the two species are I = 0.317 and D = 1.149. At the same time, the long-standing systematic ciliata—limicola problem remains unsolved and requires further investigations because the well-known “boring” species, P. ciliata was first described as living in fine, soft mud.

Through analyses of water and sediments, we investigate tungsten and 14 other heavy metals in a stream receiving treated effluents from a semiconductor manufacturer-clustered science park in Taiwan. Treated effluents account for ∼ 50% of total annual river discharge and1% of total sediment discharge. Dissolved tungsten concentrations in the effluents abnormally reach 400 μg/L, as compared to the world river average concentration of0.1 μg/L. Particulate tungsten concentrations are up to 300 μg/g in suspended and deposited sediments, and the corresponding enrichment factors are three orders of magnitude higher than average crust composition. Surprisingly, the estimated amount of tungsten exported to the adjacent ocean is 23.5 t/yr, which can approximate the amount from the Yangtze River should it be unpolluted. This study highlights the urgency of investigating the biological effect of such contamination.

Pygospio elegans Claparede, 1863, the type species of the genus Pygospio, was originally described from Normandy, France, and later widely reported from boreal waters in the northern hemisphere. Sequence data of four gene fragments (2576 bp in total) of the mitochondrial 16S rDNA, nuclear 18S and 28S rDNA, and Histone 3 have shown that individuals from California and Oregon, USA, Scotland and the White Sea, Russia were genetically similar (the average p-distances for the combined data between the four groups ranged from 0.04 to 0.16%, average p = 0.1%). These individuals are considered to be conspecific and the amphiboreal distribution of P. elegans is here confirmed. Adult morphology of the species is briefly described and illustrated. The molecular analysis revealed two genetically distant populations, Pygospio sp. 1 from the Sea of Okhotsk and Pygospio sp. 2 from Oregon. The morphological differences and high average genetic p-distances for the combined data (ranging from 3.06 to 3.18%, average p = 3.12%) between Pygospio sp. 2 and P. elegans suggest the presence of an undescribed Pygospio species co-occurring with P. elegans in Oregon. High morphological similarity and moderate genetic p-distances for the combined data (ranging from 1 to 1.11%, average p = 1.07%) between Pygospio sp. 1 and P. elegans indicate a comparatively recent genetic divergence of the Pygospio population in the Sea of Okhotsk. Taking into account the high genetic similarity of the remote European and North American populations of P. elegans and medial location of the Pygospio sp. 1 population, we suggest the latter to belong to a separate species. However, this conclusion should be verified in further studies on the morphology, reproductive biology and genetics of this population. The present findings show the need to re-examine Pygospio from the Asian Pacific and elsewhere that have been identified as P. elegans.

The spionid polychaete Dipolydora giardi (Mesnil, 1896), originally described as a borer in coralline algae from northern France, was later reported world-wide boring into various shells, sponges and also inhabiting mud tubes on soft bottoms. The reported morphological variability and wide range of habitats suggested that more than one species might be involved. In the present study, D. giardi is redescribed based on some material from northern France sent by F. Mesnil in 1896 to the Zoological Museum, University of Copenhagen, and on new material collected in Italy. The species is characterized by its incised prostomium, caruncle to the end of chaetiger 3, branchiae on the anterior half of the body (usually beginning on chaetiger 10), pygidium with one ventral lobe and two smaller dorsal lobes, and heavy falcate spines of chaetiger 5 with a large lateral tooth on one side and a smaller accessory spur on the other side. Dipolydora trilobata (Radashevsky, 1993) is a closely similar species, but is maintained as distinct. Dipolydora anoculata (Moore, 1907) is probably a valid species and should be removed from the synonymy of D. giardi.

A Polydora species was found boring in shells of the abalone Haliotis discus hannai cultivated in land-based tanks in Coquimbo, Chile. Spionid polychaetes of Polydora and related genera have been reported from Chile but no worms similar to those found in abalone have been described. The abalone pest corresponds in morphology to Polydora uncinata Sato-Okoshi, 1998, a shell-boring species which was originally described from Japan and never reported from outside the country. It is suggested that occurrence of the species in Chile resulted from its accidental transportation from Japan. Adult worms were most likely transported to Coquimbo with imported abalone brood stock. Prevalence of abalone infestation by worms in Coquimbo varied substantially among cultivation tanks, reaching values as high as 98.8%. Up to 42 worms were found in one shell. The worms often caused formation of nacreous blisters which covered up to 50% of the inner shell surface. Egg capsules with developing larvae were present in female burrows. Larval development was entirely lecithotrophic, with larvae feeding on numerous nurse eggs, staying inside egg capsules until 16–17-segment stage and hatching shortly before metamorphosis. Polydora uncinata is redescribed based on individuals from Coquimbo to alert zoologists in case of accidental release of worms into Chilean coastal waters. Regardless of how the species was transported to Chile, its release to the natural ecosystem may have negative unforeseen impacts on the native fauna.

The spionid polychaete Dipolydora blakei is identified from benthic samples collected in the Aegean Sea off Chalkis and the Ionian Sea off Kalamitsi, both on the coast of Greece. Adults of D. blakei are characterized by having the falcate spines of chaetiger 5 with a large lateral tooth and bristles on the convex side of a long and pointed main fang, awl-like spines in posterior notopodia, branchiae beginning from chaetiger 7 and a pygidium with two lateral lobes. This is the first report of the species from the Mediterranean Sea and European waters and the second record (after one from Brazil) outside its type locality in deep-water off New England in the north-west Atlantic Ocean. The morphology of the Greek specimens is described and illustrated and diagnostic characters of the species are discussed. The origin of these specimens in the coastal waters of Greece is uncertain and the species is considered as cryptogenic in the Mediterranean Sea. An identification key to Dipolydora species with bristle-topped falcate spines in chaetiger 5 known from the Mediterranean Sea and European waters is provided.

This is the third guide in a series aimed to help in the identification of northern European samples through the NationalMarine Biological Analytical Quality Control (NMBAQC) Scheme. A review is presented of general morphology andbiology of one of the most common groups in marine and estuarine communities worldwide, spionid polychaetes(Annelida: Spionidae). An identification key to 20 genera and a list of 80 species likely to occur in waters around Britainand Ireland are provided based on the taxonomic literature, collection records and the author’s examination of various collections. The names are updated but some records need verification.

The spionid mudworm Polydora cornuta Bosc, 1802 (formerly Polydora ligni Webster, 1880) is redescribed based on museum and new material collected in temperate and subtropical zones worldwide. Previously unobserved features are noted, including arrangement of lateral ciliated organs on all chaetigers but 4 and 5, metanephridial organs and glandular pouches beginning from chaetiger 7. Larval morphology is described and illustrated based on material from Brazil. The larvae are characterized by middorsal vesiculate melanophores from chaetiger 3 or 4, dorsal paired melanophores band-shaped from chaetiger 3 and ramified from chaetiger 7 or 8, large ramified yellow chromatophores on ventral side from chaetigers 5–7, specific modified chaetae in notopodia of chaetiger 5, and hooks in neuropodia from chaetiger 7 not accompanied by any other kind of chaetae. Some differences from earlier descriptions of larvae from Europe and North America are highlighted. Consistent morphological differences between adults from distantly separated populations, as suggested in earlier studies, were not revealed and all the examined materials are referred to one species.