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At least 37 records · Page 2Linked to original sources
PubMed2003

External gestation of Exogone naidina Oersted, 1845 (Polychaeta, Syllidae): ventral attachment of eggs and embryos.

The external gestation of sexually ripe females of the species Exogone naidina (Polychaeta, Syllidae) is described by means of SEM and TEM analysis. The eggs, embryos and juveniles are attached in close vicinity of each parapodial complex in a position immediately below each ventral cirrus and are connected to the female by a cup like structure. The formation of this adhesive disk is linked to secretory cells scattered between dermal cells of ripe female. This adhesive disk is present only in sexually mature animals and is considered as epitokous structure. The evolutive significance of ventral and dorsal attachment found within the Exogoninae is also discussed.

Animals↗
PubMed1996

Development of an in vivo genotoxicity assay using the marine worm Platynereis dumerilii (Polychaeta: Nereidae).

An in vivo genotoxicity test system has been developed using the embryo-larval stages of the marine annelid, Platynereis dumerilii (Polychaeta: Nereidae). This species is representative of an ecologically important group of marine invertebrates, it is amenable to laboratory culture and has a well defined and stable karyotype (2n=28) which is suitable for the analysis of a range of cytogenetic endpoints, including chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs). An evaluation of the cell cycle kinetics using the embryo-larval stages allowed selection of exposure times for cytogenetic work. Subsequently, 12-h-old embryos were exposed to reference mutagens, dissolved in sea water, in the presence of 5-bromodeoxyuridine (BrdU) for 12 h (SCE analysis) or 8 h (CA analysis) at 15 +/- 1 degree C, by which time they had reached the first larval stage (20-24h). Dose response-relationships for cytotoxicity, SCEs and CAs were observed for both direct acting mutagens (methyl methanesulfonate, mitomycin C) and mutagens which require metabolic activation (cyclophosphamide, benzo[a]pyrene). The sensitivity of the embryo-larval stages of P. dumerilii to both direct and indirect acting mutagens, their suitability for laboratory culture, together with the presence of a good karyotype and chromosome morphology for cytogenetic analyses, makes this species a potentially valuable in vivo model for marine genotoxicity testing.

Animals↗
PubMed2004

Adrenoceptor compounds prevent the settlement of marine invertebrate larvae: Balanus amphitrite (Cirripedia), Bugula neritina (Bryozoa) and Hydroides elegans (Polychaeta).

The effects of the neurotransmitter blockers idazoxan and phentolamine on the larval settlement of three marine invertebrate species belonging to three different phyla were investigated by using in vitro concentration-response bioassays. Since neurotransmitters are known to influence metamorphic transitions in invertebrate larvae, neurotransmitter blockers were tested to evaluated their sublethal effects on larvae. The alpha-adrenergic antagonists idazoxan and phentolamine inhibited settlement of Balanus amphitrite (Cirripedia), Bugula neritina (Bryozoa) larvae, and larvae of the polychaete Hydroides elegans (Polychaeta) in a concentration-and taxon-dependent manner. At concentrations of 10(-3) M of both agents, larvae of all three species became immobile and subsequently died within 24 h. While cumulative settlement rates were observed after 48 h for B. amphitrite and H. elegans, and after 5 h for B. neritina, >90% of the larvae that settled did so within 24 h for the first two species and within 1 h for B. neritina. The tendency of the hydrophobic idazoxan and phentolamine to accumulate at solid surfaces most probably contributes to their successful inhibition of larval settlement. This ability makes them particularly attractive as candidates for the development of slow-release carriers in antifouling paints.

Adrenergic alpha-Antagonists↗
PubMed1989

The spermatozoa of the polychaeta (Annelida): an ultrastructural review.

1. Polychaete sperm are divisible into ect-aquasperm, ent-aquasperm, and introsperm. 2. Ect-aquasperm are the commonest type of polychaete sperm and are considered plesiomorphic for the Polychaeta. Re-evolution of ect-aquasperm (as neo-aquasperm) is, nevertheless, tentatively hypothesized for some Sabellida. 3. In terms of ultrastructural studies of sperm in the investigated polychaete families, only ect-aquasperm have been demonstrated for 16 families; only ent-aquasperm for 3 families; ect- and ent-aquasperm for 3; ect- and intro-sperm for 2; ect-, ent- and intro-sperm for 1 family; and only introsperm for 11 families but investigations can only be regarded as preliminary. To date no family is known to have ent- and intro-sperm only. Sperm ultrastructure has yet to be examined in the orders Magelonida, Psammodrilida, Cossurida, Spintherida, Sternapsida, Flabelligerida and Fauvelopsida. 4. Much variation occurs in gross morphology, ultrastructure and configuration of the several components of ect-aquasperm: acrosome, nucleus, mitochondria, and centrioles and associated anchoring apparatus. A 9 + 2 axoneme is constant. 5. Group-specific sperm structure has been demonstrated for the Nereidae (chiefly ect-aquasperm), and for introsperm of the families Histriobdellidae, Questidae; Capitellidae, Spionidae and Protodrilidae. Species-specificity of all classes of spermatozoa is well established. 6. The very small size of ect-aquasperm is correlated with production of large numbers of sperm as an adaptation to broadcast spawning. Simplicity of structure may relate more to conservation of materials than to hydrodynamics. 7. Fertilization by ent-aquasperm requires fewer eggs than in external fertilization and is accompanied by a tendency to lecithotrophy. Elongation of the nucleus and development of asymmetry are seen in several of the few known examples of ent-aquasperm. Whether modifications are related to transfer or to other features, such as lecithotrophy, is uncertain. 8. Evident multiple origins of polychaete introsperm contraindicate their value in establishing relationship between families, in contrast with their utility in groups such as decapod crustacea. 9. At the intrafamilial level polychaete introsperm have taxonomic and phylogenetic value, as seen in the Spionidae, Capitellidae, and Histriobdellidae, and are distinctive of each of these and other families. 10. At higher taxonomic levels, the ultrastructure of the sperm of the oligochaetoid Questidae distinguishes this family from euclitellates, each class of which has its own distinctive subtype of the euclitellate introsperm. 11.(ABSTRACT TRUNCATED AT 400 WORDS)

Acrosome↗
PubMed2004

Ellipsomyxa gobii (Myxozoa: Ceratomyxidae) in the common goby Pomatoschistus microps (Teleostei: Gobiidae) uses Nereis spp. (Annelida: Polychaeta) as invertebrate hosts.

Nereis diversicolor O.F. Müller and N. succinea Frey et Leuckart (Polychaeta, Nereidae) living in brackish shallow areas in Denmark are naturally infected with tetractinomyxon actinospores. Infected Nereis spp. were experimentally fed to various potential fish hosts, and the actinosporean stages developed into myxosporean stages of Ellipsomyxa gobii Køie, 2003 (Ceratomyxidae) in the gallbladder of the common goby Pomatoschistus microps (Krøyer) (Gobiidae). The European eel Anguilla anguilla (L.), three-spined stickleback Gasterosteus aculeatus L., small sand eel Ammodytes tobianus L., flounder Platichthys flesus (L.), European plaice Pleuronectes platessa L. and common sole Solea solea (L.) did not become experimentally infected. In Danish shallow brackish areas P. microps is naturally infected with E. gobii, in some areas with a prevalence >90%. We compared small subunit ribosomal DNA sequences of the actinosporean with E. gobii from P. microps. Sequences were identical, which further verifies that both forms belong to the same organism. This is the first myxozoan two-host life cycle in the marine environment.

Animals↗
PubMed2004

Feeding behavior of the cirratulid Cirriformia filigera (Delle Chiaje, 1825) (Annelida: Polychaeta).

Observations of the feeding behavior of Cirriformia filigera (Delle Chiaje, 1825) (Annelida: Polychaeta) from the intertidal zone of São Francisco and Engenho D'água beaches (São Sebastião, State of São Paulo) were made in the laboratory. This species, like other cirratulids, is a deposit feeder, feeding mainly on sediment surface with the aid of its grooved and ciliated palps, which are used to capture food particles. The worm lies just beneath the substrate surface in a J-shaped tube. When feeding, it extends up to 4 palps over the sediment surface, capturing food particles which pass down the groove of each palp directly to the mouth. Only fine sand grains are ingested. The worm frequently extends 4 branchial filaments into the overlying water for aeration. When it moves with the prostomium sideways, it collects and transports sand grains that pass backwards along its ventral region until reaching the middle part of its body. Next, the parapodia and palps move the sand grains to the dorsal posterior end of the animal, covering this area with sand. Some sand grains are also ingested as the worm moves.

Animals↗
PubMed2003

A new species of Alcyonosyllis Glasby and Watson, 2001 (Polychaeta: Syllidae: Syllinae) from Shimoda, Japan, commensal with the gorgonian Melithaea flabellifera.

A new species of Alcyonosyllis Glasby and Watson, 2001 (Polychaeta: Syllidae: Syllinae) is described from shallow water of Shimoda, Izu Peninsula, Japan. The worms were commensal with the gorgonian Melithae flabellifera (Kükenthal, 1909). Alcyonosyllis glasbyi n. sp. differs from all other species of the genus in having a single chaeta per parapodium. The genus is new to Japan.

Animals↗
PubMed2004

Sabellaria tottoriensis n. sp. (Annelida: Polychaeta: Sabellariidae) from shallow water off Tottori, the Sea of Japan.

A new species of the genus Sabellaria Lamarck, 1812 (Annelida: Polychaeta: Sabellariidae), is described from shallow water off Tottori, the Sea of Japan. Sabellaria tottoriensis n. sp., is gregarious with tubes constructed of sand and shell debris. The new species is distinguished by the character combination of 1 or 2 pairs of nuchal spines, two forms (long and short) of opercular paleae in the middle row, with the slender blades of long ones recurved outward. Detailed morphological features of the species are described and compared with other Japanese and worldwide congeners.

Animals↗
PubMed2004

Two new species of Spiochaetopterus (Annelida: Polychaeta) from Sagami Bay and Tokyo Bay, Central Japan with a comparative table of species from Japanese and adjacent waters.

Two new species of Spiochaetopterus (Chaetopteridae: Polychaeta), S. sanbanzensis, from Sanbanze, off Ichikawa and Funabashi Cities, Tokyo Bay, and S. izuensis from the shallow waters of Sagami Bay, were described. The most obvious difference is the number of segments in region A: 9 in S. sanbanzensis and 10 in S. izuensis. In addition, Spiochaetopterus sanbanzensis has elliptical light brown or blackish eye-spots, asymmetrical cordate specialized A4 chaetae, and a color pattern consisting of many dispersed brown spots on both ventral and dorsal faces of region A. In Spiochaetopterus izuensis, a brown band extends from each eye-spot to the level of the A1 chaetae; the convex ventral edge of the head of the specialized A4 chaeta has an oblique section and the color pattern of the body is absent. A comparison is established between these two new species and other known species from Indo-Pacific Ocean.

Animals↗
PubMed2001

[Syllinae (Syllidae: Polychaeta) of the Parque Nacional de Coiba, Panama].

Four expeditions were made to Coiba National Park between 1996 and 1998 to characterize this part of the poorly known Panamian Pacific polychaete fauna. The samples were collected by SCUBA diving, either by removing 4 kg blocks of dead coral (Pocillopora sp.) or scraping off 25 x 25 cm quadrats of Telesto multiflora or algae (Dyctiota cf. flavellata, Padina cf. durvillaei and another currently unidentified species). This paper deals with the Syllinae from hard substrates. Twenty-two species belonging to six genera of the subfamily Syllinae Grube, 1850 (Syllidae: Polychaeta) are reported. A new species, Syllis castroviejoi, is described. Four species are newly reported for the Eastern Pacific: Syllis beneliahuae (Campoy & Alquézar, 1982), S. botosaneanui (Hartmann-Schröder, 1973), S. corallicola Verrill, 1900 and S. garciai (Campoy, 1982), and, likewise, two species are first reports for the Central American Pacific coast: Branchiosyllis pacifica Rioja, 1941 and Syllis truncata Haswell, 1920. Two species, Syllis magna (Westheide, 1974) and S. pigmentata (Chamberlin, 1919), are newly reported for Panama.

Animals↗
PubMed2001

[Syllidae (Polychaeta) from Thalassia testudinum beds at Morrocoy National Park (Venezuela)].

A total of 40 species of syllids (Polychaeta: Syllidae) inhabiting Thalassia testudinum beds in Morrocoy National Park, Venezuela, belonging to 13 genera, are reported; 36 species are new for Venezuela: Branchiosyllis exilis, B. oculata, Eusyllis lamelligera, Exogone arenosa, E. breviantennata, E. naidinoides, E. naidina, E. parahomoseta mediterranea, Grubeosyllis clavata, G. heterocirra, Odontosyllis detecta, O. enopla, O. gibba, Opisthosyllis brunnea, Plakosyllis brevipes, Sphaerosyllis bilobata, S. glandulata, S. magnidentata, S. piriferopsis, S. riseri, S. longilamina, S. taylori, Syllis alosae, Syllis riojai, n. comb., S. beneliahui, S. broomensis, S. cornuta, S. corallicola, S. garciai, S. hyalina, S. lutea, S. mexicana, S. prolifera, S. sardai and Xenosyllis scabra.

Animals↗
PubMed2001

Some Nereididae (Annelida: Polychaeta) from the Pacific Coast of Costa Rica.

Fifteen species of Nereididae (Annelida: Polychaeta) belonging to nine genera are reported from the subtidal and intertidal of the Pacific Coast of Costa Rica. A new species, Nereis costaricaensis, is described. Laeonereis brunnea Hartmann-Schröder 1959 is removed from synonomy with L. culveri (Webster 1880) while Perinereis seridentata (Hartmann-Schröder 1959) is moved from the genus Neanthes based upon the presence of bar-shaped paragnaths on area VI of the proboscis. The presence of Neanthes micromma Harper 1979 is an extension of the range of this species from the Gulf of California and Neanthes roosevelti Hartman 1939 is the first record of this species since its description from the Galapagos. A taxonomic key to these nereidid species is included.

Animals↗
PubMed2001

Capitellidae (Annelida: Polychaeta) from the Pacific Coast of Costa Rica.

Eleven species of Capitellidae (Annelida: Polychaeta) belonging to eight genera are reported from the subtidal and intertidal of the Pacific Coast of Costa Rica. Three species, Mediomastus ambiseta, M. californiensis and Notomastus hemipodus, are found in highest abundances and are widespread in subtidal and intertidal environments. A taxonomic key to these species is included.

Animals↗
PubMedDate not supplied

[Sphinctocystis phyllodoces gen. n., sp. n. (Eugregarinida: Lecudinidae)--a new gregarine from Phyllodoce citrina (Polychaeta: Phyllodocidae)].

UNLABELLED: A new species of aseptate gregarine, Sphinctocystis phyllodoces gen. n., sp. n., from the gut of a polychaete Phyllodoce citrina Malmgren, 1865 from White Sea is described. The electron and light microscopic data on trophozoits are presented. Taxonomy of the described species is discussed. Certain ultrastructural characters are included in generic and specific diagnoses. Order Eugregarinida Leger, 1900; suborder Aseptata Chakravarty, 1960; family Lecudinidae Kamm, 1922. DIAGNOSIS: Characters of the family. Free trophozoits elongated, often with several annular constrictions. Anterior end asymmetric, without hooks, not separated from the body, with small apical papilla encircled by smooth area. Epicyte "classical", without additional axial formations at the tops of folds; epicytic folds high, monomorphic in cross sections, finger-shaped, with parallel sidewalls. In the gut of polychaetes. DIFFERENTIAL DIAGNOSIS: The new genus differs from Lecudina by having asymmetric anterior end, developed smooth area around the apical papilla, and monomorphic epicytic folds looking finger-shaped in cross sections. It also differs from Lankesteria by the absence of additional axial formations at the tops of the epicytic folds. It differs from both named genera by presence of annular constrictions on the trophozoit body. Sphinctocystis phyllodoces sp. n. DIAGNOSIS: Characters of the genus. Free trophozoits elongated, large, up to 617 x x 77 um. The average height of epicytic folds 976 nm, thickness 194 nm; there are 6-8 apical filaments and rippled dense structures per fold. Nucleus spherical (ellipsoid after fixation), 24-52 microm along longest axis, localised in anterior third of the body, carries several karyosomes of various size; 25-30 nm thick fibrils (possible fragments of nucleolonema) may be present in karyolymph. Other stages unknown. TYPE SERIES: Microscope preparation with 7 trophozoits, Karacci's haematoxylin stained, is kept in the Zoological museum of the Moscow State University (collection number: Z-1). TYPE HOST: Phyllodoce citrina Malmgren, 1865 (Polychaeta: Phyllodocidae). LOCALISATION: Mid-gut. TYPE LOCALITY: White Sea Biological Station of the Moscow State University, Yeremeyevsky Rapid, Velikaya Salma Strait, Kandalaksha Bay, White Sea.

Animals↗
PubMed1986

[Structure of the neuropile of the abdominal trunk of Oweniidae (Polychaeta, Oweniidae)].

By means of vital staining with methylene blue, structural organization of the abdominal nerve trunk has been studied in the Polychaeta--Myriochele oculata Zachs. Topographic relations of sensitive, motor and associative neurons of the neuropil are demonstrated. Overwhelming majority of the trunk nerves are unipolar, and a small part--bipolar. The sensitive and motor elements of the neuropil have not any strict zonal localization and are situated in it both dorsally and ventrally. The associative apparatus is presented by a system of short links. The abdominal trunk is a non-paired formation. During evolution of the Oweniidae, there, probably, took place a process on inclusion of the sensitive bipolar neurons into the composition of the associative apparatus of the abdominal trunk.

Animals↗
PubMedDate not supplied

[2 new species of gregarines parasites of annelides: Pleurocystis eiseniellae of Eiseniella tetraedra Sav.)Oligochaeta), Pterospora petaloprocti of Petaloproctus terricola Quatr. (Polychaeta)].

The first species belongs to the genus Pleurocystis (in the Oligocheta host, Eiseniella tetraedra). It is characterized by early syzygies with lateral connection and navicular sporocysts with similar poles. It differs from the only species already described of the genus and is named Pleurocystis eiseniellae n. sp. The second one is related to the genus Pterospora (in the Polychaeta host, Petaloproctus terricola) but differs from the three species already known by its size and number of terminal digitations in specimens always found in syzygy. The sporocysts with dissimilar poles (one rounded, the other neck-shaped) show a loose epispore. This Gregarine in named Pterospora petaloprocti n. sp.

Animals↗
PubMed2005

Ultrastructure and localization of a visual Gq protein in hypertrophied epitoke ocelli of Perinereis brevicirris (Polychaeta, Annelida).

Functional ultrastructural changes in the rhabdomeric photoreceptors of the cerebral ocelli are described for normal and sexually mature (epitoke) Perinereis brevicirris (Polychaeta, Annelida). With sexual maturation, the cerebral ocelli hypertrophied, increasing in volume to 5.5 times that of ocelli in the normal state, and the thickness of the retinal layer increased up to 10 times. Perinereis ocelli have a pigmented retinal layer consisting of at least two cell types: photoreceptor cell (PR) and pigmented supporting cells (PS). In epitoke ocelli, PR bear well-developed rhabdomeric microvilli, multilamellar bodies, and numerous cytoplasmic membranous structures, including vesicles, smooth endoplasmic reticulum, and secondary lysosomes. Localization of a visual Gq protein in the ocelli was studied with anti-GqC antibody. The antibody strongly labeled not only microvilli and multilamellar bodies throughout the retinal layer, but also secondary lysosomes and vesicles in the cytoplasm of the PR in the epitoke ocelli, although labeling was observed only in the microvilli and multilamellar bodies in normal ocelli. Reverse transcription/polymerase chain reaction analysis revealed that the amount of G protein alpha subunit mRNA in the epitoke head increased by roughly twice that of the normal head. Since Gq protein is essential for phototransduction in Perinereis ocelli, these results suggest that the sites are involved in photoreceptive membrane turnover, which occurs much more extensively in epitoke ocelli. Thus, epitoke ocelli may represent a model system for studying rhabdomeric photoreceptive membrane turnover.

Animals↗
PubMed1988

The ultrastructure of the spermatozoon in Pisione remota (Annelida: Polychaeta) and its transformation in the receptaculum seminis.

The spermatozoon of Pisione remota and its transformation after transmission into the female are unique within Polychaeta. Most prominent organelles of the rod-shaped aflagellate gamete in the male are an elongate nucleus formed like a canoe, a parallel arranged vacuole-like structure with a peripheral network of cisternae, and mitochondria and lamellar bodies on both ends of the cell. In the female the vacuole-like structure detaches from the nucleus and is obviously phagocytosed by a receptacle cell. The nucleus is largely expanded. The cytoplasmic sheath of the sperm differentiates to form a system of pseudopod-like projections that envelop the apical projections of the receptacle cells. The structures and their transformations are considered to be related to a long-term storage of the sperm in the female.

Animals↗