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<TITLE>RE: [Annelida] Internal fertilization in Terebellidae</TITLE>
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<P DIR=LTR><SPAN LANG="en-au"><B>Hi Maua, please check if the following references are of any use to you. I have ignored the Dani´s papers on the topic since you may have them all. Regards, Salva</B></SPAN></P>
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<P DIR=LTR><SPAN LANG="en-au">Molecular analysis indicates gene flow among populations of Paralvinella pandorae Desbruyeres and Laubier 1986 (Alvinellidae, Terebellida), a polychaete annelid endemic to hydrothermal vents of the northeast PacificAuthor(s): Knowles JD, Wenink E, Schult N, Tunnicliffe V, McHugh D Source: MARINE ECOLOGY-AN EVOLUTIONARY PERSPECTIVE Volume: 26 Issue: 3-4 Pages: 216-222 Published: SEP-DEC 2005 Abstract: The polychaete annelid Paralvinella pandorae Desbruyeres and Laubier 1986 is endemic to hydrothermal vents in the northeast Pacific, and is found at almost all vents sites along the 500-km long Juan de Fuca ridge (JdF) system. The sperm morphology of P. pandorae indicates that fertilization occurs internally or in the worm's tube, and the maximum observed oocyte size of 215 mu m suggests that a dispersive larval phase is short or non-existent. Size frequency analyses of populations of P. pandorae suggest continuous or semi-continuous recruitment of juveniles. Given Our limited knowledge of the species' life history, we predicted that populations of P. pandorae would exhibit a decline in genetic similarity with increasing distance among populations along the JdE While our attempts to use amplified fragment length polymorphisms to test this prediction were not successful, our analysis of cytochrome oxidase I gene sequences provided insights into the phylogeography of the species. For 31 individuals from five sites along the JdF there is little sequence variation among individuals and no phylogeographic pattern among haplotypes from populations separated by distances of Lip to 210 km. These results indicate that gene flow occurs among all sites in the analyses, i.e. despite the very limited dispersal potential inferred from life history characteristics of this worm, there is no evidence for isolation-by-distance across the geographical scale of the study. Demersal larvae dispersed by near-bottom currents might explain the gene flow among sites, as well as the establishment of populations of P. pandorae at new vents within a year.</SPAN></P>
<P DIR=LTR><SPAN LANG="en-au">Oogenesis characteristics in the hydrothermal vent polychaete Alvinella pompejanaAuthor(s): Pradillon F, Gaill F Source: INVERTEBRATE REPRODUCTION & DEVELOPMENT Volume: 43 Issue: 3 Pages: 223-235 Published: JUL 2003 Times Cited: 2 References: 35 Citation Map Abstract: The morphology of the female genital tract and mechanisms of oogenesis were investigated through light and transmission electron microscopy in the vent polychaete Alvinella pompejana. We showed that the genital pore exhibits different morphologies in males and females and can be used for sex identification. The female genital tract consists of two oviducts that contain mature oocytes and spermathecae, which may contain a few unfertilised oocytes, and simultaneously spermatozoa. Ultrastructural analysis of both coelomic and genital tract oocytes showed that vitellogenesis is mostly achieved in the coelomic cavity, apparently without helper cells, and involves autosynthetic mechanisms of yolk production. Such a mechanism suggests that egg growth is slow. It is commonly admitted that hydrothermal environments are unpredictable and highly variable, and thus, may favour species that are able to produce eggs rapidly facing environmental changes. As Alvinella pompejana does not seem to follow such a reproductive pattern, we hypothesised that the reproductive process may be considered as a two-step process where only the second one would be directly influenced by the environment. First, coelomic vitellogenesis would be a relatively slow process, regulated physiologically independently of abrupt environmental changes. In the second step, mature eggs would be selected and stored for further spawning and fertilisation, at any time triggered by environmental cues or biological signal such as sperm transfer.</SPAN></P>
<P DIR=LTR><SPAN LANG="en-au">REPRODUCTIVE-BIOLOGY AND POPULATION-STRUCTURE OF THE DEEP-SEA HYDROTHERMAL VENT WORM PARALVINELLA-GRASSLEI (POLYCHAETA, ALVINELLIDAE) AT 13-DEGREES-N ON THE EAST PACIFIC RISEAuthor(s): ZAL F, JOLLIVET D, CHEVALDONNE P, DESBRUYERES D Source: MARINE BIOLOGY Volume: 122 Issue: 4 Pages: 637-648 Published: JUN 1995 Times Cited: 39 References: 57 Citation Map Abstract: Paralvinella grasslei is a polychaetous annelid living in the harsh, unstable and heterogeneous environmental conditions found at deep-sea hydrothermal vent sites in the eastern Pacific. The aim of this work was to examine the possible influence of the reproductive biology of P. grasslei on the structure of its populations. Maximum observed oocyte size inside the oviduct is 275 mu m, and fecundity is relatively low. Examination of gametes and young specimens suggested a direct benthic development for this species. The population structure of P. grasslei at 13 degrees N/EPR (EPR = East Pacific Rise) revealed a discontinuous recruitment which seems to be synchronized within vent sites and fields. The data also suggested the occurrence of discrete breeding periods. P. grasslei probably reproduces several times a year, with an apparent periodicity. Tidal signals could be a possible cue for the coordination of the reproductive cycle. The life-history of P. grasslei is discussed in light of the reproductive biology of other terebellomorph polychaetes, and seems to be well adapted for colonizing the unstable environment of hot vents. Two main hypotheses can explain the dissemination processes of this species along axial oceanic ridges. The influence of near-bottom currents occurring along the central ''graben'' of the East Pacific Rise can be considered to account for part of the transport of larvae and juveniles, but the observations of polychaete erpochaetes on the test of hydrothermal bythograeid crabs and evidence that crab migrations occur between vents also support the possibility of zoochory for the dissemination of alvinellid polychaetes.</SPAN></P>
<P DIR=LTR><SPAN LANG="en-au">ULTRASTRUCTURE OF SPERMATIDS AND SPERMATOZOA IN RAMEX-CALIFORNIENSIS AND NICOLEA-ZOSTERICOLA (TEREBELLIDAE, POLYCHAETA)Author(s): ROUSE GW, MCHUGH D Source: OPHELIA Volume: 39 Issue: 3 Pages: 225-238 Published: AUG 1994 Abstract: The ultrastructure of the spermatozoa and some stages of spermiogenesis in Ramex californiensis Hartman, 1944 and Nicolea zostericola (Orsted, 1844) is described. Both species brood direct developing larvae, N. zostericola outside the tube in a jelly mass, and R. californiensis inside the tube in a cocoon. In both species, spermatids were seen in large groups of synchronously developing cells. Each spermatid was connected via a cytoplasmic bridge to a central cytophore. The acrosome initially developed at the posterior end of the spermatid near the centrioles. It then migrated to the anterior end of the sperm at the tip of the nucleus; in N. zostericola the migration was much later than in R. californiensis. No microtubular activity was involved in spermiogenesis. The mature sperm nuclei of R. californiensis and N. zostericola were basically cylindrical and elongate, measuring 9 mum and 10 mum in length, respectively. In both species the acrosome was bullet-shaped, although in N. zostericola the subacrosomal space was proportionally much larger, and there were two regions of differing electron density. There was no sperm midpiece in either species. Instead the mitochondria lay in grooves along the posterior region of the nucleus; 2 mitochondria in R. californiensis sperm and 4 mitochondria in N. zostericola. The anchoring apparatus for the sperm of each species consisted of both the proximal and distal centrioles, and a complex satellite apparatus arising from the distal centriole. The morphology of the sperm is compared with other polychaetes; functional aspects and systematic implications are discussed. The close similarity of the sperm between N. zostericola and R. californiensis does suggest a similar fertilization mechanism is used by the two species. Until a phylogenetic hypothesis for the Terebellidae is developed the evolutionary change in sperm morphology and functional correlates with other factors in reproduction cannot be determined.</SPAN></P>
<P DIR=LTR><SPAN LANG="en-au">A COMPARATIVE-STUDY OF REPRODUCTION AND DEVELOPMENT IN THE POLYCHAETE FAMILY TEREBELLIDAEAuthor(s): MCHUGH D Source: BIOLOGICAL BULLETIN Volume: 185 Issue: 2 Pages: 153-167 Published: OCT 1993 Abstract: The reproduction and development of four species of terebellid polychaetes from the west coast of North America were studied and compared with several other terebellid species to reveal the covariation of life history traits in the group, and assess any limitations on terebellid life history evolution that may be imposed by ancestry or body design. The four species in the present study span the range of reproductive and developmental modes known for the family Terebellidae. Eupolymnia crescentis and Neoamphitrite robusta are both free spawners that reproduce during discrete 3-month breeding periods. In E. crescentis, oogenesis takes from 5 to 8 months and spawning occurs from July to September, maximum oocyte diameter is 210 mum, and fecundity reaches approximately 128,500 during a single breeding period. The E. crescentis larva develops near the bottom for about 7 days before settling as a five-setiger juvenile. Neoamphitrite robusta reproduces from April to July after a 12-month oogenic cycle; oocytes in this species measure up to 180 mum, and fecundity reaches approximately 830,000. The two brooders in the study, Ramex californiensis and Thelepus crispus, brood their larvae in the maternal tube. T. crispus reproduces continuously for at least 6 months, and has up to 51,500 larvae in a single brood. The oocytes in this species (400 mum) give rise to larvae that are brooded to the one-setiger stage and then emerge to undergo a one-day planktonic period before the larvae settle and become juveniles at eight setigers. Ramex californiensis reproduces continuously year round; larvae are brooded in cocoons that are laid sequentially in the tube, with up to 44 larvae in a single cocoon. Development from the 4 1 0 mum oocytes is direct, and juveniles have 11 setigers. Unlike E. crescentis and N. robusta, in which oogenesis is synchronized within individuals to produce a peak of large oocytes during the discrete spawning period, R. californiensis and T. crispus females have a wide range of oocyte sizes throughout the year. </SPAN></P>
<P DIR=LTR><SPAN LANG="en-au">Correlation analysis and analysis of variance of reproductive and developmental traits of these and several other terebellid species revealed some expected trends. For example, egg size varies according to the mode of reproduction (free spawning, extratubular brooding, or intratubular brooding), and is also correlated with juvenile size. However, egg size does not predict fecundity in terebellids when body size is held constant, and brooding is not restricted to small-bodied species. Indeed, the largest and smallest species in the study brood their larvae intratubularly, suggesting that allometric constraints may not be important in determining mode of reproduction in these polychaetes. The Terebellidae is a diverse family found in all marine habitats, yet all known terebellid larvae are non-feeding; this contrasts with the occurrence of both planktotrophy and lecithotrophy in other polychaete families, and leads to the proposal that larval development in terebellids has been constrained during the evolution of the lineage. The results of this study demonstrate that generalizations regarding complex relationships among life history traits are often inappropriate. The need for more comparative studies of marine invertebrate reproduction and development, and the integration of phylogenetic analyses into the study of life history evolution in marine invertebrates is highlighted.</SPAN></P>
<P DIR=LTR><SPAN LANG="en-au">LARVAL DEVELOPMENT OF POLYCHAETA FROM THE NORTHERN CALIFORNIA COAST V RAMEX-CALIFORNIENSIS HARTMAN (POLYCHAETA, TEREBELLIDAE)Author(s): BLAKE JA Source: BULLETIN OF MARINE SCIENCE Volume: 48 Issue: 2 Pages: 448-460 Published: MAR 1991 Abstract: Ramex californiensis is a small intertidal terebellid polychaete that lives in rocky habitats on the northern California coast. The species is abundant under colonies of encrusting tunicates in the low intertidal zone on rocks protected from the surf. The tubes are formed of coarse mucoid secretions covered with sand, shell, and algal fragments. Large elongated, white eggs ranging from 270 to 330-mu-m (XBAR = 292-mu-m) are deposited by females in capsules within the tubes. Up to 16 eggs or embryos have been observed in a single capsule. One, two, or three capsules may be found in a single tube. When multiple capsules are present, the embryos contained in separate capsules are always at different stages of development, indicating sequential fertilizations and egg deposition. Pair formation between males and females was not observed. Development is direct and occurs entirely within the capsules. The earliest larval stages are covered with cilia and bear a pair of red, granular eyes. The anterior and posterior ends elongate and the cilia become restricted to an anterior band. The oral structures develop early, with the differentiation of a ciliated vestibule and development of a medial tentacle on the anterior end of the prostomium. The tentacle assists movement within the capsule during their early development. Two additional tentacles appear lateral to the original medial tentacle and develop each a ciliated groove. The latest encapsulated stages have three grooved tentacles, 10-11 segments (eight with capillary notosetae; none with uncini), and a fully developed digestive tract containing remants of yolk. Upon release from the capsule, an additional pair of tentacles develops and uncini first appear on setiger 3. Juveniles were maintained on cultures of unicellular algae covering the bottoms of the culture dishes. The worms grazed upon these algae by sweeping their tentacles over the bottom where they pick up the cells and transport them to the vestibule. Juveniles secrete thin mucous tubes.</SPAN></P>
<P DIR=LTR><SPAN LANG="en-au">Title: DIVERSITY IN REPRODUCTIVE-ORGANS AND REPRODUCTION IN PACIFIC TEREBELLID POLYCHAETES </SPAN></P>
<P DIR=LTR><SPAN LANG="en-au">Author(s): SMITH RI</SPAN></P>
<P DIR=LTR><SPAN LANG="en-au">A COMPARATIVE-STUDY OF REPRODUCTIVE ENERGETICS IN 2 POPULATIONS OF THE TEREBELLID POLYCHAETE EUPOLYMNIA-NEBULOSA MONTAGU WITH DIFFERENT REPRODUCTIVE MODESAuthor(s): GREMARE A Source: JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY Volume: 96 Issue: 3 Pages: 287-302 Published: MAY 1986 </SPAN></P>
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