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| 2. |
- Aguado, M. T., et al.
(författare)
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Species delimitation in Amblyosyllis (Annelida, Syllidae)
- 2019
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- Amblyosyllis is a worldwide distributed group of annelids mainly found in coastal environments. It is well known among the polychaete specialists mostly because of its notable beauty, showing bright colourful patterns and outstanding long and coiled appendices. Amblyosyllis is a monophyletic genus easy to identify due to its distinct diagnostic features; however, the species and their boundaries are, in most cases, not well defined. Herein, we provide an extensive sample of Amblyosyllis material (115 specimens) from several world geographic areas. We have studied the morphological features of each specimen and photographed them alive. Two mitochondrial DNA markers (COI and 16S) and one nuclear gene fragment (28S, D1 region) were sequenced. We performed phylogenetic analyses based on each DNA partition, as well as the combined data sets, obtaining congruent results. Species delimitation methods such as distance analyses, statistical parsimony networks and multi-rate Poisson tree processes were also applied. The combined results obtained from different methodologies and data sets are used to differentiate between, at least, 19 lineages compatible with the separately evolving meta-populations species concept. Four of these lineages are identified as nominal species, including the type species of Amblyosyllis, A. rhombeata. For three other lineages previously synonymized names are recovered, and seven lineages are described as new species. All of these species are described and supported by appropriate iconography. We recognize several morphological characters useful to identify species of Amblyosyllis, which in some cases should also be combined with molecular methods for species delineation. The genetic divergence in the genus is high, contrary to the morphological homogeneity observed. Two species show a wide geographical distribution, while the rest have a more restricted distribution. There are several examples of species with overlapping distribution patterns.
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| 3. |
- Andrade, S. C. S., et al.
(författare)
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Articulating "Archiannelids": Phylogenomics and Annelid Relationships, with Emphasis on Meiofaunal Taxa
- 2015
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Ingår i: Molecular Biology and Evolution. - : Oxford University Press (OUP). - 0737-4038 .- 1537-1719. ; 32:11, s. 2860-2875
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Tidskriftsartikel (refereegranskat)abstract
- Annelid disparity has resulted in morphological-based classifications that disagree with phylogenies based on Sanger sequencing and phylogenomic analyses. However, the data used for the latter studies came from various sources and technologies, involved poorly occupied matrices and lacked key lineages. Here, we generated a new Illumina-based data set to address annelid relationships from a fresh perspective, independent from previously generated data and with nearly fully occupied matrices. Our sampling reflects the span of annelid diversity, including two symbiotic annelid groups (Myzostomida and Spinther) and five meiofaunal groups once referred to as part of Archiannelida (three from Protodrilida, plus Dinophilus and Polygordius). As well as the placement of these unusual annelids, we sought to address the overall phylogeny of Annelida, and provide a new perspective for naming of major clades. Our results largely corroborate the phylogenomic results of Weigert et al. (2014; Illuminating the base of the annelid tree using transcriptomics. Mol Biol Evol. 31: 1391-1401), with "Magelona + Owenia" and Chaetopteridae forming a grade with respect to all other annelids. Echiura and Sipuncula are supported as being annelid groups, with Sipuncula closest to amphinomids as sister group to Sedentaria and Errantia. We recovered the three Protodrilida terminals as sister clade to Phyllodocida and Eunicida (=clade Aciculata). We therefore place Protodrilida as part of Errantia. Polygordius was found to be sister group to the scaleworm terminal and the possibility that it is a simplified scaleworm clade, as has been shown for the former family Pisionidae, is discussed. Our results were equivocal with respect to Dinophilus, Myzostomida, and Spinther possibly owing to confounding long-branch effects.
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| 4. |
- Bertrand, Yann, et al.
(författare)
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Taxonomic surrogacy in biodiversity assessments, and the meaning of Linnaean ranks
- 2006
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Ingår i: Systematics and Biodiversity. ; 4:2, s. 149-159
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Tidskriftsartikel (refereegranskat)abstract
- The majority of biodiversity assessments use species as the base unit. Recently, a series of studies have suggested replacing numbers of species with higher ranked taxa (genera, families, etc.); a method known as taxonomic surrogacy that has an important potential to save time and resources in assesments of biological diversity. We examine the relationships between taxa and ranks, and suggest that species/higher taxon exchanges are founded on misconceptions about the properties of Linnaean classification. Rank allocations in current classifications constitute a heterogeneous mixture of various historical and contemporary views. Even if all taxa were monophyletic, those referred to the same rank would simply denote separate clades without further equivalence. We conclude that they are no more comparable than any other, non-nested taxa, such as, for example, the genus Rattus and the phylum Arthropoda, and that taxonomic surrogacy lacks justification. These problems are also illustrated with data of polychaetous annelid worms from a broad-scale study of benthic biodiversity and species distributions in the Irish Sea. A recent consensus phylogeny for polychaetes is used to provide three different family-level classifications of polychaetes. We use families as a surrogate for species, and present Shannon–Wiener diversity indices for the different sites and the three different classifications, showing how the diversity measures rely on subjective rank allocations
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| 5. |
- Borda, E., et al.
(författare)
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Cryptic species of Archinome (Annelida: Amphinomida) from vents and seeps
- 2013
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Ingår i: Proceedings of the Royal Society B-Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 280:1770
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Tidskriftsartikel (refereegranskat)abstract
- Since its description from the Galapagos Rift in the mid-1980s, Archinome rosacea has been recorded at hydrothermal vents in the Pacific, Atlantic and Indian Oceans. Only recently was a second species described from the Pacific Antarctic Ridge. We inferred the identities and evolutionary relationships of Archinome representatives sampled from across the hydrothermal vent range of the genus, which is now extended to cold methane seeps. Species delimitation using mitochondrial cytochrome c oxidase subunit I (COI) recovered up to six lineages, whereas concatenated datasets (COI, 16S, 28S and ITS1) supported only four or five of these as clades. Morphological approaches alone were inconclusive to verify the identities of species owing to the lack of discrete diagnostic characters. We recognize five Archinome species, with three that are new to science. The new species, designated based on molecular evidence alone, include: Archinome levinae n. sp., which occurs at both vents and seeps in the east Pacific, Archinome tethyana n. sp., which inhabits Atlantic vents and Archinome jasoni n. sp., also present in the Atlantic, and whose distribution extends to the Indian and southwest Pacific Oceans. Biogeographic connections between vents and seeps are highlighted, as are potential evolutionary links among populations from vent fields located in the east Pacific and Atlantic Oceans, and Atlantic and Indian Oceans; the latter presented for the first time.
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| 6. |
- Dahlgren, Thomas G., 1963, et al.
(författare)
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Morphological and molecular evidence of the phylogeny of Nereidiform polychaetes (Annelida)
- 2000
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Ingår i: Journal of Zoological Systematics and Evolutionary Research. - 0947-5745. ; 38:4, s. 249-253
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Tidskriftsartikel (refereegranskat)abstract
- The phylogeny of Nereidiformia is assessed in a parsimony analysis of combined morphological and DNA data, with special focus on previously questioned relationships between Chrysopetalidae and Hesionidae, between Pilargidae and Hesionidae, and the affinities of Hesionides and Microphthalmus. A 660 by segment of the mtDNA cytochrome c oxidase subunit I gene was sequenced for two chrysopetalids, one nereidid, one pilargid, one pisionid, two hesionids, plus the two questionable hesionids Hesionides arenaria and Microphthalmus sp. Phylogenetic resolution was poor for the cytochrome c oxidase subunit I gene data alone, but the combined analysis yielded partially robust topologies, suggesting that nereids are the sister group to chrysopetalids, and that pilargids, Hesionides and Microphthalmus do not belong within the hesionids.
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| 7. |
- Dahlgren, Thomas G., 1963, et al.
(författare)
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On the generic allocation of Chrysopetalum caecum
- 1995
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Ingår i: Mitteilongen aus dem Hamburgschischen zoologischen Museum und Institut. ; 92:Ergänzungsband 1, s. 159-173
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Tidskriftsartikel (refereegranskat)
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| 8. |
- Eklöf, Jenny, 1975, et al.
(författare)
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Phylogeny of benthic Phyllodocidae (Polychaeta) based on morphological and molecular data
- 2007
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Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903. ; 45:1, s. 261-271
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Tidskriftsartikel (refereegranskat)abstract
- A combined molecular (18S rDNA, 28S rDNA, 16S rDNA and COI) and morphological analysis of the benthic phyllodocids is presented for the first time. Nineteen phyllodocids and two outgroup taxa are assessed using parsimony, maximum likelihood and Bayesian analyses. We demonstrate high degrees in homoplasy in the traditionally used morphological phyllodocid characters, and show that all the three current subfamilies Phyllodocinae, Eteoninae and Notophyllinae are non-monophyletic. The genera Eulalia, Eumida, Protomystides, Pseudomystides, Pterocirrus and Sige form a well-supported group, as does Mystides and Nereiphylla. Another clade with strong support includes Eteone and Paranaitis, although with Eteone nested within a paraphyletic Paranaitis. The relationship between these two taxa indicate that the unusual arrangement of modified cirri on the first segments in Eteone is due to a fusion of segment 1 and 2 where the cirri of segment 1 have been reduced. Eulalia is non-monophyletic and should be split, minimally into two groups. Our results are ambiguous regarding the ancestral phyllodocid condition of absence–presence of median antenna or nuchal papilla and uniramous or biramous parapodia, but shows that the absence of cirri on segment 3 (previously an apomorphy, for e.g., Mystides, Pseudomystides and Hesionura) is maximally homoplastic.
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| 9. |
- Glasby, C. J., et al.
(författare)
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Worms by number
- 2008
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Ingår i: Proceedings of the Royal Society B-Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 275:1647, s. 2071-2076
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates alternation patterns in length, shape and orientation of dorsal cirri (fleshy segmental appendages) of phyllodocidans, a large group of polychaete worms (Annelida). We document the alternation patterns in several families of Phyllodocida (Syllidae, Hesionidae, Sigalionidae, Polynoidae, Aphroditidae and Acoetidae) and identify the simple mathematical rule bases that describe the progression of these sequences. Two fundamentally different binary alternation patterns were found on the first four segments: 1011 for nereidiform families and 1010 for aphroditiform families. The alternation pattern in all aphroditiform families matches a simple one-dimensional cellular automaton and that for Syllidae (nereidiform) matches the Fibonacci string sequence. Hesionidae (nereidiform) showed the greatest variation in alternation patterns, but all corresponded to various known substitution rules. Comparison of binary patterns of the first 22 segments using a distance measure supports the current ideas on phylogeny within Phyllodocida. These results suggest that gene(s) involved in post-larval segmental growth employ a switching sequence that corresponds to simple mathematical substitution rules.
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| 10. |
- Kato, T., et al.
(författare)
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A revision of Notophyllum Orsted, 1843 (Phyllodocidae, Polychaeta)
- 2002
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Ingår i: Journal of Natural History. - 0022-2933. ; 36:10, s. 1135-1178
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Tidskriftsartikel (refereegranskat)abstract
- Notophyllum Orsted, 1843 (Phyllodocidae, Polychaeta) is revised based on all available types and a large number of newly collected specimens. Redescriptions are provided of the seven species considered valid: N. americanum Verrill, 1885, N. foliosum (Sars, 1835), N. imbricatum Moore, 1906, N. japonicum Marenzeller, 1879, N. multicirris (Grube, 1878), N. sagamianum Izuka, 1912 and N. splendens (Schmarda, 1861). Notophyllum imajimai sp. n. is described from Japan. Some previously unreported characters are introduced, including a series of proboscis characters, morphology of dorsal cirri and cirrophores, and first appearance of notoaciculae in non-cephalized segments. A parsimony analysis of these taxa is presented based on 20 morphological characters and indicates two well-supported clades: Notophyllum as traditionally delineated and (N. foliosum, N. americanum (N. imajimai sp. n., N. imbricatum)). Characters for distinguishing all species of Notophyllum are provided in a table. Previous identifications of Notophyllum species have relied on the number of nuchal lobes; it is demonstrated that extensive intraspecific variation and interspecific overlap complicate the use of this character. Notophyllum caecum Fauvel, 1913 is referred to as Notophyllinae incertae sedis, and N. tectum (Chamberlin, 1919) comb. n. and N. laciniatum Willey, 1905 are referred to as Notophyllum incertae sedis. Taxa removed from Notophyllum include Phyllodoce benedenii (Hansen, 1882) comb. n. and Sige antarctica (Hartman, 1978) comb. n.
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