| 1. |
- Claverie, Thomas, et al.
(författare)
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Spawning aggregations and mass movements in subtidal Onchidoris bilamellata (Mollusca Opisthobranchia)
- 2008
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Ingår i: Journal of the Marine Biological Association of the United Kingdom. - : Cambridge University Press. - 0025-3154 .- 1469-7769. ; 88:1, s. 157-159
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Tidskriftsartikel (refereegranskat)abstract
- Little is known about spawning aggregations in subtidal populations of the nudibranch Onchidoris bilamellata. We provide photographic evidence of the spawning aggregations and associated spawning migrations or mass movements whose occurrence was debated.
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| 2. |
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| 3. |
- Skovgaard, Alf, et al.
(författare)
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Observation of live specimens of Pseudotontonia cornuta (Ciliophora : Oligotrichida) reveals new distinctive characters
- 2005
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Ingår i: Journal of the Marine Biological Association of the United Kingdom. - 0025-3154 .- 1469-7769. ; 85:4, s. 783-786
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Tidskriftsartikel (refereegranskat)abstract
- A large planktonic ciliate, Pseudotontonza cornuta, was observed during a cruise in the North Sea, Denmark, in summer 2001. Live cells as well as fixed and protargol-stained specimens were studied. The species possessed the characteristic tail of Tontoniidae, somatic cillature classifying it as a Pseudotontonia, and cell proportions and oral ciliature corresponding to P cornuta. Observation of live cells, however, revealed distinctive features as chloroplast- containing tentacles emerging just below the apical membranelles and an S-shaped proximal rim of the left margin of the oral cavity. These characters are eye-catching in live specimens, but have passed unnoticed till now because all previous studies on P cornuta have been made on fixed samples.
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| 4. |
- Stach, Thomas, et al.
(författare)
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Nerve cells of Xenoturbella bocki (phylum uncertain) and Harrimania kupfferi (Enteropneusta) are positively immunoreactive to antibodies raised against echinoderm neuropeptides
- 2005
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Ingår i: Journal of the Marine Biological Association of the United Kingdom. - : Cambridge University Press. - 0025-3154 .- 1469-7769. ; 85:6, s. 1519-1524
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Tidskriftsartikel (refereegranskat)abstract
- The phylogenetic position of Xenoturbella spp. has been uncertain since their discovery in 1949. It has been recently suggested that they could be related to Ambulacraria within Deuterostomia. Ambulacraria is a taxon that has been suggested to consist of Hemichordata and Echinodermata. The hypothesis that X. bocki was related to Ambulacraria as well as the hypothesis of a monophyletic Ambulacraria is primarily based on the analysis of DNA sequence data. We tested both phylogenetic hypotheses using antibodies raised against SALMFamide 1 and 2 (S1, S2), neuropeptides isolated from echinoderms, on X. bocki and the enteropneust Harrimania kupfferi. Both species showed distinct positive immunoreactivity against S1 and S2. This finding supports the Ambulacraria-hypothesis and suggests a close phylogenetic relationship of X. bocki to Ambulacraria. In particular, the presence of immunoreactivity against S2 can be interpreted as a synapomorphy of Enteropneusta, Echinodermata, and Xenoturbella spp.
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| 5. |
- Stöhr, Sabine, et al.
(författare)
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Morphological diagnosis of the two genetic lineages ofAcrocnida brachiata(Echinodermata: Ophiuroidea), with description of a new species
- 2009
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Ingår i: Journal of the Marine Biological Association of the United Kingdom. - : Cambridge University Press (CUP). - 0025-3154 .- 1469-7769. ; 90:4, s. 831-843
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Tidskriftsartikel (refereegranskat)abstract
- The burrowing brittle-starAcrocnida brachiatahas so far been regarded as a single, easily identifiable species. Recent studies showed habitat-related differences in maximum size, life span, breeding time and recruitment between intertidal and subtidal populations, which at first were attributed to environmental effects on individuals within the same species. Molecular data, however, strongly suggested the existence of two distinct lineages and ultimately two cryptic species with clear bathymetric segregation. Morphological evidence had so far not been presented, because any differences were interpreted as intraspecific variation. We collectedA. brachiatafrom intertidal and subtidal habitats at the coast of Brittany, France, and examined 15 specimens of each group externally by SEM. A key character ofA. brachiatais that the scales at the edge of the disc and on the ventral side are conically enlarged. Intertidal individuals showed a sparser disc scalation, more spine-like than conical ventral disc scales and spatulate, distally widened arm spines. In addition, we dissected several specimens of different size and examined the internal skeleton by SEM. The oral plates showed a rib-like structure on their abradial face that differs between individuals from either habitat. Subtidal specimens have fewer ribs than intertidal ones. These consistent differences support the existence of two species withinA. brachiata. To describe the second species, we needed to establish the identity ofA. brachiata. We describe a neotype, because no type material has been preserved since it was first described; it corresponds mainly to subtidal samples. The new species is described asAcrocnida spatulispinasp. nov. The taxonomic status ofAcrocnidahas been debated over the years with reference to its close affinities withAmphiura chiajei. We compared the species ofAcrocnidawithA. chiajeiandAmphiura filiformisand found thatAcrocnidais indeed morphologically similar toA. chiajei, among other characters by a similar oral plate structure, whereasA. filiformisdiffers greatly fromAcrocnidaas well asA. chiajei. Most strikingly, it has a different type of oral plate. These findings indicate that fundamental taxonomic changes may need to be made in the family Amphiuridae in the future.
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| 6. |
- Svanberg, Ingvar
(författare)
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Human usage of mermaid's glove sponge (Isodictya palmata) on the Faroes
- 2007
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Ingår i: Journal of the Marine Biological Association of the United Kingdom. - 0025-3154 .- 1469-7769. ; 87:6, s. 1773-1775
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Tidskriftsartikel (refereegranskat)abstract
- There is very little documentation on the economic importance of locally available marine sponges (Porifera) in north-western Europe. From Iceland and the Faroe Islands there are records of naming and using the so-called mermaid's glove sponge (Isodictya palmata) especially for cleaning purposes. As late as in the 1940s, school children in the Faroe Islands gathered this sponge and used it to clean the slate.
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| 7. |
- Tiemann, Henry, et al.
(författare)
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Documentation of potential courtship-behaviour in Periphylla periphylla (Cnidaria : Scyphozoa)
- 2009
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Ingår i: Journal of the Marine Biological Association of the United Kingdom. - 0025-3154 .- 1469-7769. ; 89:1, s. 63-66
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Tidskriftsartikel (refereegranskat)abstract
- The distribution pattern and nocturnal surface behaviour of the deep-sea medusa Periphylla periphylla in a Norwegian fjord was studied. Medusa abundance, size distribution and condition were determined, using surface collections, net tows and ROV-based video profiles. Only larger, mature medusae reached the surface and aggregated into small groups of both sexes, whereas juvenile medusae remained in deeper waters. Observations on the behaviour and cytology of aggregated medusae suggested a mating strategy. We hypothesize that this behaviour is the by-product of a holopelagic life history, developed in a more oceanic deep environment with low species abundance, as surface aggregation increases the chance of encounter and mating.
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| 8. |
- Davenport, J., et al.
(författare)
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Doses of darkness control latitudinal differences in breeding date in the barnacle Semibalanus balanoides
- 2005
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Ingår i: Journal of the Marine Biological Association of the United Kingdom. - 0025-3154. ; 85:1, s. 59-63
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports the first study of breeding in the boreo-arctic barnacle Semibalanus balanoides in which latitudinal variation in timing of egg mass hardening has been examined simultaneously over the geographical scale involved, thereby excluding temporal confounding of the data. The timing of autumn egg mass hardening on the middle shore was established in 2002 and 2003 at ten stations ranging latitudinally from Trondheim (63 degrees 24'N) to Plymouth (50 degrees 18'N). To assess variation at local scale (< 10 km), breeding was studied on three shores at each of two Irish locations (Cork and Galway). At Oban (Scotland) and Cork, the effect of shore height on timing of breeding was investigated. A strong influence of latitude and day length on timing of breeding was found in both 2002 and 2003. In both years, barnacles bred much earlier (when day length was longer) at high rather than low latitudes. No significant effect of environmental temperature or insolation on timing of breeding was detected. Shores no more than 10 km apart showed minimal difference in middle shore breeding date (< 4 days). However, upper shore barnacles bred significantly earlier (by 7-13 days) than middle shore animals. The data indicate that breeding is controlled by period of daily darkness, with high shore annuals encountering longer effective 'nights' because of the opercular closure response to emersion (which will reduce light penetration to tissues). Predictions concerning the effects of global changes in climate and cloud cover on breeding and population distribution are made. It is suggested that increased cloud cover in the northern hemisphere is likely to induce earlier breeding, and possibly shift the present southern limit of Semibalanus southwards.
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| 9. |
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| 10. |
- Wiklund, Helena, 1965, et al.
(författare)
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The phylogenetic relationships between Amphinomidae, Archinomidae and Euphrosinidae (Amphinomida: Aciculata: Polychaeta), inferred from molecular data
- 2008
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Ingår i: Journal of the Marine Biological Association of the UK. - 0025-3154. ; 88:3, s. 509-513
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Tidskriftsartikel (refereegranskat)abstract
- Amphinomida is an ‘isolated’ clade within the polychaete group Aciculata and traditionally includes the families Amphinomidae, Archinomidae and Euphrosinidae. Archinomidae were erected for a single species, the hydrothermal vent polychaete Archinome rosacea. Originally, A. rosacea was assigned to Euphrosinidae although it shares more morphological similarities with Amphinomidae. In this study we assess the position of Archinome, Euphrosinidae and Amphinomidae by using molecular data from nuclear 18S rDNA and 28S rDNA. Parsimony, maximum likelihood and Bayesian analyses are performed on the nucleotide datasets covering in total 19 terminals from Amphinomidae, Euphrosinidae, Archinomidae and outgroups. Our results conclusively show that Euphrosinidae and Amphinomidae are sister taxa and that Archinome is sister to Chloeia within Amphinomidae. Based on these results the family name Archinomidae is treated as a junior synonym of Amphinomidae.
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