Skip to main content
NCBI home page
Proceedings of the Royal Society B: Biological Sciences logoLink to Proceedings of the Royal Society B: Biological Sciences
. 1998 Apr 7;265(1396):631–640. doi: 10.1098/rspb.1998.0341

A robust molecular phylogeny of the Tricladida (Platyhelminthes: Seriata) with a discussion on morphological synapomorphies.

S Carranza 1, D T Littlewood 1, K A Clough 1, I Ruiz-Trillo 1, J Baguñà 1, M Riutort 1
PMCID: PMC1689013  PMID: 9881470

Abstract

The suborder Tricladida (Platyhelminthes: Turbellaria, Seriata) comprises most well-known species of free-living flatworms. Four infraorders are recognized: (i) the Maricola (marine planarians); (ii) the Cavernicola (a group of primarily cavernicolan planarians); (iii) the Paludicola (freshwater planarians); and (iv) the Terricola (land planarians). The phylogenetic relationships among these infraorders have been analysed using morphological characters, but they remain uncertain. Here we analyse the phylogeny and classification of the Tricladida, with additional, independent, molecular data from complete sequences of 18S rDNA and 18S rRNA. We use maximum parsimony and neighbour-joining methods and the characterization of a unique gene duplication event involving the Terricola and the dugesiids to reconstruct the phylogeny. The results show that the Maricola is monophyletic and is the primitive sister group to the rest of the Tricladida (the Paludicola plus the Terricola). The Paludicola are paraphyletic since the Terricola and one paludicolan family, the Dugesiidae, share a more recent common ancestor than the dugesiids with other paludicolans (dendrocoelids and planariids). A reassessment of morphological evidence may confirm the apparent redundancy of the existing infraorders Paludicola and Terricola. In the meantime, we suggest replacing the Paludicola and Terricola with a new clade, the Continenticola, which comprises the families Dugesiidae, Planariidae, Dendrocoelidae and the Terricola.

Full Text

The Full Text of this article is available as a PDF (237.8 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. AX P. [Relationships and phylogeny of Turbellaria]. Ergeb Biol. 1961;24:1–68. [PubMed] [Google Scholar]
  2. Adoutte A., Philippe H. The major lines of metazoan evolution: summary of traditional evidence and lessons from ribosomal RNA sequence analysis. EXS. 1993;63:1–30. doi: 10.1007/978-3-0348-7265-2_1. [DOI] [PubMed] [Google Scholar]
  3. Bayascas J. R., Castillo E., Muñoz-Mármol A. M., Saló E. Planarian Hox genes: novel patterns of expression during regeneration. Development. 1997 Jan;124(1):141–148. doi: 10.1242/dev.124.1.141. [DOI] [PubMed] [Google Scholar]
  4. Carranza S., Baguñ J., Riutort M. Are the Platyhelminthes a monophyletic primitive group? An assessment using 18S rDNA sequences. Mol Biol Evol. 1997 May;14(5):485–497. doi: 10.1093/oxfordjournals.molbev.a025785. [DOI] [PubMed] [Google Scholar]
  5. Carranza S., Giribet G., Ribera C., Baguñ, Riutort M. Evidence that two types of 18S rDNA coexist in the genome of Dugesia (Schmidtea) mediterranea (Platyhelminthes, Turbellaria, Tricladida). Mol Biol Evol. 1996 Jul;13(6):824–832. doi: 10.1093/oxfordjournals.molbev.a025643. [DOI] [PubMed] [Google Scholar]
  6. Chirgwin J. M., Przybyla A. E., MacDonald R. J., Rutter W. J. Isolation of biologically active ribonucleic acid from sources enriched in ribonuclease. Biochemistry. 1979 Nov 27;18(24):5294–5299. doi: 10.1021/bi00591a005. [DOI] [PubMed] [Google Scholar]
  7. Dover G. Molecular drive: a cohesive mode of species evolution. Nature. 1982 Sep 9;299(5879):111–117. doi: 10.1038/299111a0. [DOI] [PubMed] [Google Scholar]
  8. 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]
  9. Gunderson J. H., Sogin M. L., Wollett G., Hollingdale M., de la Cruz V. F., Waters A. P., McCutchan T. F. Structurally distinct, stage-specific ribosomes occur in Plasmodium. Science. 1987 Nov 13;238(4829):933–937. doi: 10.1126/science.3672135. [DOI] [PubMed] [Google Scholar]
  10. Hillis D. M., Dixon M. T. Ribosomal DNA: molecular evolution and phylogenetic inference. Q Rev Biol. 1991 Dec;66(4):411–453. doi: 10.1086/417338. [DOI] [PubMed] [Google Scholar]
  11. Kishino H., Hasegawa M. Evaluation of the maximum likelihood estimate of the evolutionary tree topologies from DNA sequence data, and the branching order in hominoidea. J Mol Evol. 1989 Aug;29(2):170–179. doi: 10.1007/BF02100115. [DOI] [PubMed] [Google Scholar]
  12. Lake J. A. Reconstructing evolutionary trees from DNA and protein sequences: paralinear distances. Proc Natl Acad Sci U S A. 1994 Feb 15;91(4):1455–1459. doi: 10.1073/pnas.91.4.1455. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Littlewood D. T., Smith A. B. A combined morphological and molecular phylogeny for sea urchins (Echinoidea: Echinodermata). Philos Trans R Soc Lond B Biol Sci. 1995 Jan 30;347(1320):213–234. doi: 10.1098/rstb.1995.0023. [DOI] [PubMed] [Google Scholar]
  14. Rohde K. Phylogeny of Platyhelminthes, with special reference to parasitic groups. Int J Parasitol. 1990 Dec;20(8):979–1007. doi: 10.1016/0020-7519(90)90041-k. [DOI] [PubMed] [Google Scholar]
  15. Smith S. W., Overbeek R., Woese C. R., Gilbert W., Gillevet P. M. The genetic data environment an expandable GUI for multiple sequence analysis. Comput Appl Biosci. 1994 Dec;10(6):671–675. doi: 10.1093/bioinformatics/10.6.671. [DOI] [PubMed] [Google Scholar]
  16. Telford M. J., Holland P. W. Evolution of 28S ribosomal DNA in chaetognaths: duplicate genes and molecular phylogeny. J Mol Evol. 1997 Feb;44(2):135–144. doi: 10.1007/pl00006130. [DOI] [PubMed] [Google Scholar]
  17. Thompson J. D., Higgins D. G., Gibson T. J. CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choice. Nucleic Acids Res. 1994 Nov 11;22(22):4673–4680. doi: 10.1093/nar/22.22.4673. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Woese C. R. Bacterial evolution. Microbiol Rev. 1987 Jun;51(2):221–271. doi: 10.1128/mr.51.2.221-271.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Proceedings of the Royal Society B: Biological Sciences are provided here courtesy of The Royal Society

RESOURCES