New insights into polychaete phylogeny (Annelida) inferred from 18S rDNA sequences

Bleidorn, Christoph; Vogt, Lars; Bartolomaeus, Thomas

doi:10.1016/s1055-7903(03)00107-6

Cited by 171 publications

(141 citation statements)

References 26 publications

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“…The main disagreement seems to be whether the ancestral larva was feeding or not. Mapping of larval types onto a phylogeny is problematic due to the lack of a generally accepted phylogeny of the Annelida (compare Rouse and Fauchald, '97;Westheide et al, '99;Giribet et al, 2000;Peterson and Eernisse, 2001;Struck et al, 2002;Bleidorn et al, 2003). However, the observations of two types of ciliary feeding in larvae of Armandia and Urechis (Miner et al,'99; see above) with the downstreamcollecting method used by the early stages indicate that the various other types of ciliary feeding described above are derived.…”

Section: Discussion Of Annelid Developmentmentioning

confidence: 99%

See 1 more Smart Citation

Trochophora larvae: Cell‐lineages, ciliary bands, and body regions. 1. Annelida and Mollusca

2004

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The trochophora concept and the literature on cleavage patterns and differentiation of ectodermal structures in annelids (''polychaetes'') and molluscs are reviewed. The early development shows some variation within both phyla, and the cephalopods have a highly modified development. Nevertheless, there are conspicuous similarities between the early development of the two phyla, related to the highly conserved spiral cleavage pattern. Apical and cerebral ganglia have almost identical origin in the two phyla, and the cell-lineage of the prototroch is identical, except for minor variations between species. The cell-lineage of the metatrochs is almost unknown, but the telotroch of annelids and the ''telotroch'' of the gastropod Patella originate from the 2d-cell, as does the gastrotroch in the few species which have been studied. The segmented annelid body, i.e. the region behind the peristome, develops through addition of new ectoderm from a ring of 2d-cells just in front of the telotroch. This whole region is thus derived from 2d-cells. Conversely, the mollusc body is covered by descendants of cells from both the C and D quadrants and a growth zone is not apparent. This supports the notion that the molluscs are not segmented like the annelids, and that the repeated structures seen in polyplacophorans and monplacophorans do not represent a segmentation homologous to that of the annelids.

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Section: Discussion Of Annelid Developmentmentioning

confidence: 99%

“…It should be pointed out that I regard both echiurans and pogonophorans as annelids (Nielsen, 2001; see also Hessling, 2002;Hessling and Westheide, 2002;Halanych et al, 2002;Bleidorn et al, 2003).…”

Section: Annelid Developmentmentioning

confidence: 99%

Trochophora larvae: Cell‐lineages, ciliary bands, and body regions. 1. Annelida and Mollusca

2004

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“…In the case of the echiurans, once treated as a separate phylum, it is clear that they nest within the Annelida (e.g. Bleidorn et al 2003), although the fossil record is almost mute. A somewhat different category of enigmatic metazoans are the quasi-flatworm or even quasi-protistan groups.…”

Section: Opening the Door Into The Cambrianmentioning

confidence: 99%

Darwin's dilemma: the realities of the Cambrian ‘explosion’

Morris

2006

Phil. Trans. R. Soc. B

152

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The Cambrian 'explosion' is widely regarded as one of the fulcrum points in the history of life, yet its origins and causes remain deeply controversial. New data from the fossil record, especially of Burgess Shale-type Lagerstätten, indicate, however, that the assembly of bodyplans is not only largely a Cambrian phenomenon, but can already be documented in fair detail. This speaks against a much more ancient origin of the metazoans, and current work is doing much to reconcile the apparent discrepancies between the fossil record, including the Ediacaran assemblages of latest Neoproterozoic age and molecular 'clocks'. Hypotheses to explain the Cambrian 'explosion' continue to be generated, but the recurrent confusion of cause and effect suggests that the wrong sort of question is being asked. Here I propose that despite its step-like function this evolutionary event is the inevitable consequence of Earth and biospheric change.

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“…Bleidorn et al 2006) and combined 18S, 28S, and elongation factor 1-α data clearly supports a nested position within annelids for the sipunculids. Loss of segmentation has to be assumed for sipunculids in this case, and same must be assumed (convergently) for the echiurids, where studies using 18S (Bleidorn et al, 2003) as well as the above mentioned X th EMOP, August 2008 dataset by Struck et al (2007) strongly supports a sistergroup relationship to the segmented capitellid polychaetes. Interestingly, Hessling & Westheide (2002) reported the presence of serially repeated units in the nervous system of echiurids which correspond to typical metameric ganglia of the Annelida.…”

Section: Trochozoamentioning

confidence: 99%

“…However the relationships of these two to taxa to other Trochozoa is still unresolved and even monophyly -in both cases strongly supported through morphological characters -has often been not recovered for these taxa (e.g. Bleidorn et al, 2003). Some researchers consider molluscs closely related to annelids (e.g.…”

Section: Trochozoamentioning

confidence: 99%

Lophotrochozoan relationships and parasites. A snap-shot

Bleidorn

2008

Parasite

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Summary :Lophotrochozoa has been consistently recovered in molecular phylogenetic analyses using different markers. Current knowledge of lophotrochozoan relationships is reviewed and the place that parasites occupy in this phylogeny is discussed. Two major taxa are identified within Lophotrochozoa: Platyzoa and Trochozoa. Monophyly of both taxa is still under debate. Relationships within Trochozoa remain largely unclear, however, there is strong evidence that the so called "minor phyla" Sipuncula, Echiura, and Myzostomida are all nested within annelids. Monophyly of the former "Lophophorata" is rejected, and a close relationship between phoronids and brachiopods, as well as between bryozoans and kamptozoans is suggested instead. The movement of the field of systematics into the genomic era will greatly improve our knowledge in the near future.

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New insights into polychaete phylogeny (Annelida) inferred from 18S rDNA sequences

Cited by 171 publications

References 26 publications

Trochophora larvae: Cell‐lineages, ciliary bands, and body regions. 1. Annelida and Mollusca

Trochophora larvae: Cell‐lineages, ciliary bands, and body regions. 1. Annelida and Mollusca

Darwin's dilemma: the realities of the Cambrian ‘explosion’

Lophotrochozoan relationships and parasites. A snap-shot

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