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- Erséus, Christer, 1951, et al.
(författare)
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18S rDNA phylogeny of Clitellata (Annelida).
- 2004
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Ingår i: Zoologica Scripta. - : Wiley. - 0300-3256 .- 1463-6409. ; 33:2, s. 187-196
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Tidskriftsartikel (refereegranskat)abstract
- The phylogeny of Clitellata was analysed using 18S rDNA sequences of a selection of species representing Hirudinida, Acanthobdellida, Branchiobdellida and 10 oligochaetous families. Eleven new 18S sequences of Capilloventridae (one), Haplotaxidae (one), Propappidae (one), Enchytraeidae (two), Lumbricidae (one), Almidae (one), Megascolecidae (two), Lumbriculidae (one), and Phreodrilidae (one) are reported and aligned together with corresponding sequences of 28 previously studied clitellate taxa. Twelve polychaete species were used as an outgroup. The analysis supports an earlier hypothesis based on morphological features that Capilloventridae represents a basal clade of Clitellata; in the 18S tree it shows a sister-group relationship to all other clitellates. The remaining clitellate taxa form a basal dichotomy, one clade containing Tubificidae (including the former ‘Naididae’), Phreodrilidae, Haplotaxidae, and Propappidae, the other clade with two subgroups: (1) Lumbriculidae together with all leech-like taxa (Acanthobdellida, Branchiobdellida and Hirudinida), and (2) Enchytraeidae together with a monophyletic group of all earthworms included in the study (Lumbricidae, Almidae and Megascolecidae). These earthworms are members of the taxon Crassiclitellata, the monophyly of which is thus supported by the data. The tree also shows support for the hypothesis that the first clitellates were aquatic. The position of the single species representing Haplotaxidae is not as basal as could have been expected from earlier morphology-based conclusions about the ancestral status of this family. However, if Haplotaxidae is indeed a paraphyletic assemblage of relict taxa, a higher number of representatives will be needed to resolve its exact relationships with the other clitellates.
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| 2. |
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| 3. |
- Erséus, Christer, 1951, et al.
(författare)
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Gutless marine oligochaetes and their bacterial symbionts
- 2004
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Ingår i: Abstracts, Henning XXIII "Phylogenetics and Evolutionary Biology", 23th meeting of the Willi Hennig Society, Paris, 18-23 July 2004. ; , s. 21-22
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 4. |
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| 5. |
- Hallett, S. L., et al.
(författare)
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Molecular methods clarify morphometric variation in triactinomyxon spores (Myxozoa) released from different oligochaete hosts.
- 2004
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Ingår i: Systematic Parasitology. - 0165-5752. ; 57:1, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- Thirty-nine freshwater tubificid oligochaetes were isolated, each of which harboured a triactinomyxon infection. Spore characteristics include the typical triactinomyxon anchor shape, eight germ cells within the sporoplasm and three unequal (two long and one shorter) caudal processes with square tips. Despite morphological similarities between the spores from the different hosts, their morphometrical data varied considerably; significantly, the ranges of dimensions of the smallest and largest exemplars were mutually exclusive. In order to ascertain the true number of spore types present, molecular methods were employed. Samples of waterborne spores, including the smallest and largest representatives, were selected from 11 host oligochaetes (all Tubifex tubifex Müller) and a nested PCR-RFLP `riboprint' analysis performed. The small subunit ribosomal DNA gene (18S rDNA) was targetted and amplified through two rounds of PCR, then digested with the restriction enzymes Dde I and Hha I. The resultant major cleavage patterns produced by both enzymes indicated a single triactinomyxon form; however, the pattern of several less intense bands varied between the samples. From a subset of five samples drawn from across the full spectrum of spore sizes, a 327 bp region near the 5prime was sequenced and was identical for all five samples. Comparison of this 327 bp region with that of 12 other triactinomyxons in GenBank showed 68.7–96.9% similarity (at least 9 base differences). A further 469 bp generated for each of the smallest, largest and mid-range (= reference) spore samples was identical also. The reference sample was sequenced further to yield 1,554 bp of 18S rDNA (GenBank accession number AY162270); comparison with other Myxozoa indicated this sequence was novel. The morphometrics of our triactinomyxon did not correlate with any published description. The morphometrical variation exhibited by spores of the triactinomyxon type in this study raises questions about the validity of using morphometrical data to distinguish spore types and suggests that there could be taxonomic redundancy in the diversity of actinosporeans recorded in the literature. The additional information provided by molecular data in this study was pivotal in the clarification of morphometrical variation exhibited by morphologically similar triactinomyxon spores released from different oligochaete hosts.
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| 6. |
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| 7. |
- Wang, Hongzhu, et al.
(författare)
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New species of Doliodrilus and other Limnodriloidinae (Oligochaeta, Tubificidae) from Hainan and other parts of the north-west Pacific Ocean
- 2004
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Ingår i: Journal of Natural History. - : Informa UK Limited. - 0022-2933 .- 1464-5262. ; 38:3, s. 269-299
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Tidskriftsartikel (refereegranskat)abstract
- Thirteen species of Limnodriloidinae (Tubificidae) are recorded from marine and brackish-water habitats of Hainan Island, southern China, including 11 species of Doliodrilus and two species belonging to Limnodriloides . Eight species are new to science: D. bisaccus sp. n. (types from Japan), D. longidentatus sp. n. (types from Hong Kong), D. ciliatus sp. n., D. adiacens sp. n., D. fibrisaccus sp. n. (also from Fiji), D. brachyductus sp. n., D. bidolium sp. n. and D. chinensis sp. n. In addition, material of D. puertoricensis Erseus and Milligan, 1988, from New Caledonia, is briefly described. This study shows that Doliodrilus is unexpectedly species-rich in Asian seas, in particular, around Hainan. Including an unnamed species from this island, the known members of this genus increase from three to 12.
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