TY  - JOUR
A1  - Nesnidal, Maximilian P.
A1  - Helmkampf, Martin
A1  - Meyer, Achim
A1  - Witek, Alexander
A1  - Bruchhaus, Iris
A1  - Ebersberger, Ingo
A1  - Hankeln, Thomas
A1  - Lieb, Bernhard
A1  - Struck, Torsten H.
A1  - Hausdorf, Bernhard
T1  - New phylogenomic data support the monophyly of Lophophorata and an Ectoproct-Phoronid clade and indicate that Polyzoa and Kryptrochozoa are caused by systematic bias
T2  - BMC evolutionary biology
N2  - Background: Within the complex metazoan phylogeny, the relationships of the three lophophorate lineages, ectoprocts, brachiopods and phoronids, are particularly elusive. To shed further light on this issue, we present phylogenomic analyses of 196 genes from 58 bilaterian taxa, paying particular attention to the influence of compositional heterogeneity.
Results: The phylogenetic analyses strongly support the monophyly of Lophophorata and a sister-group relationship between Ectoprocta and Phoronida. Our results contrast previous findings based on rDNA sequences and phylogenomic datasets which supported monophyletic Polyzoa (= Bryozoa sensu lato) including Ectoprocta, Entoprocta and Cycliophora, Brachiozoa including Brachiopoda and Phoronida as well as Kryptrochozoa including Brachiopoda, Phoronida and Nemertea, thus rendering Lophophorata polyphyletic. Our attempts to identify the causes for the conflicting results revealed that Polyzoa, Brachiozoa and Kryptrochozoa are supported by character subsets with deviating amino acid compositions, whereas there is no indication for compositional heterogeneity in the character subsets supporting the monophyly of Lophophorata.
Conclusion: Our results indicate that the support for Polyzoa, Brachiozoa and Kryptrochozoa gathered so far is likely an artifact caused by compositional bias. The monophyly of Lophophorata implies that the horseshoe-shaped mesosomal lophophore, the tentacular feeding apparatus of ectoprocts, phoronids and brachiopods is, indeed, a synapomorphy of the lophophorate lineages. The same may apply to radial cleavage. However, among phoronids also spiral cleavage is known. This suggests that the cleavage pattern is highly plastic and has changed several times within lophophorates. The sister group relationship of ectoprocts and phoronids is in accordance with the interpretation of the eversion of a ventral invagination at the beginning of metamorphosis as a common derived feature of these taxa.
KW  - Bryozoa
KW  - Brachiopoda
KW  - Brachiozoa
KW  - Ectoprocta
KW  - Lophophorata
KW  - Phoronida
KW  - Polyzoa
KW  - Kryptrochozoa
KW  - Compositional bias
Y1  - 2013
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/32419
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-324197
SN  - 1471-2148
N1  - © 2013 Nesnidal et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
VL  - 13
IS  - Art. 253
SP  - 1
EP  - 13
PB  - BioMed Central
CY  - London
ER  -