Phylogeny of the Metazoa Based on Morphological and 18S Ribosomal DNA Evidence

Zrzavý, Jan; Mihulka, Stanislav; Kepka, Pavel; Bezděk, Aleš; Tietz, David

doi:10.1111/j.1096-0031.1998.tb00338.x

Cited by 358 publications

(214 citation statements)

References 111 publications

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“…It includes about 100,000 extant species of both free-living and parasitic forms [3]. The conventional view of the phylum 'Platyhelminthes' is that it contains three major clades Acoelomorpha (Acoela+Nemertodermatida), Catenulida, and Rhabditophora [4], but recent phylogenetic studies based on morphological [5] and molecular evidence [6-10] have suggested non-monophyly (mostly polyphyly) of the Platyhelminthes. This is inconsistent with long-held prevailing concept of "the phylum Platyhelminthes" as defined in most zoological textbooks.…”

Section: Introductionmentioning

confidence: 99%

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et al. 2007

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Background: The parasitic Platyhelminthes (Neodermata) contains three parasitic groups of flatworms, each having a unique morphology, and life style: Monogenea (primarily ectoparasitic), Trematoda (endoparasitic flukes), and Cestoda (endoparasitic tapeworms). The evolutionary origin of complex life cyles (multiple obligate hosts, as found in Trematoda and Cestoda) and of endo-/ ecto-parasitism in these groups is still under debate and these questions can be resolved, only if the phylogenetic position of the Monogenea within the Neodermata clade is correctly estimated.

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Section: Introductionmentioning

confidence: 99%

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et al. 2007

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“…Hyman 1951) but most recent analyses (e.g. Zrzavy et al 1998; Giribet et al 2000; Peterson & Eernisse 2001; Zrzavy 2003; Glenner et al 2004) place nemerteans in an apomorphic position closer to annelids, molluscs and entoprocts (plus some other phyla varying between analyses).…”

Section: Introductionmentioning

confidence: 99%

Annulonemertes (phylum Nemertea): when segments do not count

Sundberg

Strand

2007

Biol. Lett.

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We estimated the phylogenetic position of the pseudosegmented ribbon worm Annulonemertes minusculus to test proposed evolutionary hypotheses to explain these body constrictions. The analysis is based on 18S rDNA sequences and shows that the species belongs to an apomorphic clade of hoplonemertean species. The segmentation has no phylogenetic bearing as previously discussed, but is a derived character probably coupled to the species' interstitial habitat.

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“…Anatomical distinctions have long distinguished the three principal classes, Hexactinellida, Demospongiae and Calcarea, and more recent molecular and biochemical analyses support the monophyly of the two silica-biomineralizing classes (4)(5)(6)(7). The relationship of the Calcarea is more problematic, however, with molecular evidence suggesting it may be very close to the ctenophores and cnidarians (5) and perhaps even the sister group of ''higher'' metazoans (8), making sponges as a whole paraphyletic.…”

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confidence: 97%

Reconstructing early sponge relationships by using the Burgess Shale fossil Eiffelia globosa , Walcott

Botting

Butterfield

2005

Proc. Natl. Acad. Sci. U.S.A.

104

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The relationships of the sponge classes are controversial, particularly between the calcareous and siliceous sponges. Specimens of the putative calcarean Eiffelia globosa Walcott from the Burgess Shale show the presence of diagnostic hexactinellid spicules integrated into the skeletal mesh. The arrangement of these spicules in Eiffelia is shown to be precisely equivalent to that of early protospongioid hexactinellids, and sponge growth occurred through an identical pattern to produce identical skeletal body morphology. The difference in spicule composition of the classes is interpreted through the observation of taphonomic features of Eiffelia that suggest the presence of at least two mineralogically distinct layers within the spicules. These results support molecular analyses that identify the calcarean-silicisponge transition as the earliest major sponge branch and suggest that the heteractinids were paraphyletic with respect to the Hexactinellida.Cambrian ͉ evolution ͉ Porifera ͉ stem group

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Phylogeny of the Metazoa Based on Morphological and 18S Ribosomal DNA Evidence

Cited by 358 publications

References 111 publications

Untitled

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Annulonemertes (phylum Nemertea): when segments do not count

Reconstructing early sponge relationships by using the Burgess Shale fossil Eiffelia globosa , Walcott

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