Abstract
Molecular phylogenetic analyses of aligned 18S rDNA gene sequences from articulate and inarticulate brachiopods representing all major extant lineages, an enhanced set of phoronids and several unrelated protostome taxa, confirm previous indications that in such data, brachiopod and phoronids form a well-supported clade that (on previous evidence) is unambiguously affiliated with protostomes rather than deuterostomes. Within the brachiopod-phoronid clade, an association between phoronids and inarticulate brachiopods is moderately well supported, whilst a close relationship between phoronids and craniid inarticulates is weakly indicated. Brachiopod-phoronid monophyly is reconciled with the most recent Linnaean classification of brachiopods by abolition of the phylum Phoronida and rediagnosis of the phylum Brachiopoda to include tubiculous, shell-less forms. Recognition that brachiopods and phoronids are close genealogical allies of protostome phyla such as molluscs and annelids, but are much more distantly related to deuterostome phyla such as echinoderms and chordates, implies either (or both) that the morphology and ontogeny of blastopore, mesoderm and coelom formation have been widely misreported or misinterpreted, or that these characters have been subject to extensive homoplasy. This inference, if true, undermines virtually all morphology-based reconstructions of phylogeny made during the past century or more.
Full Text
The Full Text of this article is available as a PDF (194.0 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Abouheif E., Zardoya R., Meyer A. Limitations of metazoan 18S rRNA sequence data: implications for reconstructing a phylogeny of the animal kingdom and inferring the reality of the Cambrian explosion. J Mol Evol. 1998 Oct;47(4):394–405. doi: 10.1007/pl00006397. [DOI] [PubMed] [Google Scholar]
- Aguinaldo A. M., Turbeville J. M., Linford L. S., Rivera M. C., Garey J. R., Raff R. A., Lake J. A. Evidence for a clade of nematodes, arthropods and other moulting animals. Nature. 1997 May 29;387(6632):489–493. doi: 10.1038/387489a0. [DOI] [PubMed] [Google Scholar]
- Benson D. A., Boguski M. S., Lipman D. J., Ostell J., Ouellette B. F. GenBank. Nucleic Acids Res. 1998 Jan 1;26(1):1–7. doi: 10.1093/nar/26.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cohen B. L., Stark S., Gawthrop A. B., Burke M. E., Thayer C. W. Comparison of articulate brachiopod nuclear and mitochondrial gene trees leads to a clade-based redefinition of protostomes (Protostomozoa) and deuterostomes (Deuterostomozoa) Proc Biol Sci. 1998 Mar 22;265(1395):475–482. doi: 10.1098/rspb.1998.0319. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Erber A., Riemer D., Bovenschulte M., Weber K. Molecular phylogeny of metazoan intermediate filament proteins. J Mol Evol. 1998 Dec;47(6):751–762. doi: 10.1007/pl00006434. [DOI] [PubMed] [Google Scholar]
- Field K. G., Olsen G. J., Lane D. J., Giovannoni S. J., Ghiselin M. T., Raff E. C., Pace N. R., Raff R. A. Molecular phylogeny of the animal kingdom. Science. 1988 Feb 12;239(4841 Pt 1):748–753. doi: 10.1126/science.3277277. [DOI] [PubMed] [Google Scholar]
- Halanych K. M., Bacheller J. D., Aguinaldo A. M., Liva S. M., Hillis D. M., Lake J. A. Evidence from 18S ribosomal DNA that the lophophorates are protostome animals. Science. 1995 Mar 17;267(5204):1641–1643. doi: 10.1126/science.7886451. [DOI] [PubMed] [Google Scholar]
- Halanych K. M., Bacheller J. D., Aguinaldo A. M., Liva S. M., Hillis D. M., Lake J. A. Response: lophophorate phylogeny. Science. 1996 Apr 12;272(5259):283–283. doi: 10.1126/science.272.5259.283. [DOI] [PubMed] [Google Scholar]
- Halanych K. M. The phylogenetic position of the pterobranch hemichordates based on 18S rDNA sequence data. Mol Phylogenet Evol. 1995 Mar;4(1):72–76. doi: 10.1006/mpev.1995.1007. [DOI] [PubMed] [Google Scholar]
- Hillis D. M. Inferring complex phylogenies. Nature. 1996 Sep 12;383(6596):130–131. doi: 10.1038/383130a0. [DOI] [PubMed] [Google Scholar]
- Mackey L. Y., Winnepenninckx B., De Wachter R., Backeljau T., Emschermann P., Garey J. R. 18S rRNA suggests that Entoprocta are protostomes, unrelated to Ectoprocta. J Mol Evol. 1996 May;42(5):552–559. doi: 10.1007/BF02352285. [DOI] [PubMed] [Google Scholar]
- Morris S. C., Cohen B. L., Gawthrop A. P., Cavalier-Smith T., Winnepenninckx B. Lophophorate phylogeny. Science. 1996 Apr 12;272(5259):282–283. doi: 10.1126/science.272.5259.282. [DOI] [PubMed] [Google Scholar]
- doi: 10.1098/rstb.1998.0351. [DOI] [PMC free article] [Google Scholar]
- doi: 10.1098/rstb.1998.0350. [DOI] [PMC free article] [Google Scholar]
- Stechmann A., Schlegel M. Analysis of the complete mitochondrial DNA sequence of the brachiopod terebratulina retusa places Brachiopoda within the protostomes. Proc Biol Sci. 1999 Oct 22;266(1433):2043–2052. doi: 10.1098/rspb.1999.0885. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Winnepenninckx B., Backeljau T., De Wachter R. Complete small ribosomal subunit RNA sequence of the chiton Acanthopleura japonica (Lischke, 1873) (Mollusca, Polyplacophora). Nucleic Acids Res. 1993 Apr 11;21(7):1670–1670. doi: 10.1093/nar/21.7.1670. [DOI] [PMC free article] [PubMed] [Google Scholar]
- de Rosa R., Grenier J. K., Andreeva T., Cook C. E., Adoutte A., Akam M., Carroll S. B., Balavoine G. Hox genes in brachiopods and priapulids and protostome evolution. Nature. 1999 Jun 24;399(6738):772–776. doi: 10.1038/21631. [DOI] [PubMed] [Google Scholar]