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Citation for Study 1454

Citation title: "Molecular phylogeny of African Rytidosperma-affiliated danthonioid grasses reveals generic polyphyly and convergent evolution in spikelet morphology".

This study was previously identified under the legacy study ID S1390 (Status: Published).

Citation

Verboom G., & Ntsohi R. 2005. Molecular phylogeny of African Rytidosperma-affiliated danthonioid grasses reveals generic polyphyly and convergent evolution in spikelet morphology. Taxon, null.

Authors

• Verboom G.
• Ntsohi R.

Abstract

Of the 90-95 species included in the Rytidosperma clade of grasses (Danthonioideae: Poaceae) about 20 are native to southern Africa, most of these belonging to the genera Karroochloa, Schismus and Tribolium. Whereas morphological data identify all three genera as being monophyletic, the robustness of this pattern is compromised by high levels of homoplasy. Here we use molecular data (plastid trn?L-trnF and nuclear ITS sequences) to re-evaluate phylogenetic relationships within the Rytidosperma clade, with the specific aim of testing the monophyly of the African genera. Separate parsimony analyses of the two partitions reveal low levels of incongruence, which may be attributable to incomplete lineage sorting or past hybridization. Analyses of the combined data produce well resolved, strongly supported topologies that are virtually identical, regardless of the inference method used (parsimony or Bayesian inference) or whether or not conflict taxa are included. Our data support the monophyly of the Rytidosperma clade (synapomorphies include a punctate-ovate hilum, a large embryo, and lodicule microhairs) as well as the monophyly of the Australasian-South American Rytidosperma s.l. However, the monophyly of Karroochloa, Schismus and Tribolium is strongly contradicted, all three genera being polyphyletic as currently defined. A minimum of five new combinations is required to rectify this situation. Character reconstructions reveal extensive convergence in a number of morphological features, especially those previously used to define genera. We suggest that the convergent pattern of evolution displayed by these traits, most of which describe spikelet/ diaspore morphology, is linked to their functionality in seed dispersal and burial, and that this has compromised their utility as phylogenetic markers.

About this resource

• Canonical resource URI: http://purl.org/phylo/treebase/phylows/study/TB2:S1454
• Other versions: Nexus NeXML
• Show BibTeX reference

  		@ARTICLE{TreeBASE2Ref17948,
  	 author = {G. Anthony  Verboom and Refiloe  Ntsohi},
  	 title = {Molecular phylogeny of African Rytidosperma-affiliated danthonioid grasses reveals generic polyphyly and convergent evolution in spikelet morphology},
  	 year = {2005},
  	 keywords = {},
  	 doi = {},
  	 url = {},
  	 pmid = {},
  	 journal = {Taxon},
  	 volume = {},
  	 number = {},
  	 pages = {},
  	 abstract = {Of the 90-95 species included in the Rytidosperma clade of grasses (Danthonioideae: Poaceae) about 20 are native to southern Africa, most of these belonging to the genera Karroochloa, Schismus and Tribolium. Whereas morphological data identify all three genera as being monophyletic, the robustness of this pattern is compromised by high levels of homoplasy. Here we use molecular data (plastid trn?L-trnF and nuclear ITS sequences) to re-evaluate phylogenetic relationships within the Rytidosperma clade, with the specific aim of testing the monophyly of the African genera. Separate parsimony analyses of the two partitions reveal low levels of incongruence, which may be attributable to incomplete lineage sorting or past hybridization. Analyses of the combined data produce well resolved, strongly supported topologies that are virtually identical, regardless of the inference method used (parsimony or Bayesian inference) or whether or not conflict taxa are included. Our data support the monophyly of the Rytidosperma clade (synapomorphies include a punctate-ovate hilum, a large embryo, and lodicule microhairs) as well as the monophyly of the Australasian-South American Rytidosperma s.l. However, the monophyly of Karroochloa, Schismus and Tribolium is strongly contradicted, all three genera being polyphyletic as currently defined. A minimum of five new combinations is required to rectify this situation. Character reconstructions reveal extensive convergence in a number of morphological features, especially those previously used to define genera. We suggest that the convergent pattern of evolution displayed by these traits, most of which describe spikelet/ diaspore morphology, is linked to their functionality in seed dispersal and burial, and that this has compromised their utility as phylogenetic markers.}
  }
  		

• Show RIS reference

  		TY  - JOUR
  ID  - 17948
  AU  - Verboom,G. Anthony 
  AU  - Ntsohi,Refiloe 
  T1  - Molecular phylogeny of African Rytidosperma-affiliated danthonioid grasses reveals generic polyphyly and convergent evolution in spikelet morphology
  PY  - 2005
  KW  - 
  UR  - 
  N2  - Of the 90-95 species included in the Rytidosperma clade of grasses (Danthonioideae: Poaceae) about 20 are native to southern Africa, most of these belonging to the genera Karroochloa, Schismus and Tribolium. Whereas morphological data identify all three genera as being monophyletic, the robustness of this pattern is compromised by high levels of homoplasy. Here we use molecular data (plastid trn?L-trnF and nuclear ITS sequences) to re-evaluate phylogenetic relationships within the Rytidosperma clade, with the specific aim of testing the monophyly of the African genera. Separate parsimony analyses of the two partitions reveal low levels of incongruence, which may be attributable to incomplete lineage sorting or past hybridization. Analyses of the combined data produce well resolved, strongly supported topologies that are virtually identical, regardless of the inference method used (parsimony or Bayesian inference) or whether or not conflict taxa are included. Our data support the monophyly of the Rytidosperma clade (synapomorphies include a punctate-ovate hilum, a large embryo, and lodicule microhairs) as well as the monophyly of the Australasian-South American Rytidosperma s.l. However, the monophyly of Karroochloa, Schismus and Tribolium is strongly contradicted, all three genera being polyphyletic as currently defined. A minimum of five new combinations is required to rectify this situation. Character reconstructions reveal extensive convergence in a number of morphological features, especially those previously used to define genera. We suggest that the convergent pattern of evolution displayed by these traits, most of which describe spikelet/ diaspore morphology, is linked to their functionality in seed dispersal and burial, and that this has compromised their utility as phylogenetic markers.
  L3  - 
  JF  - Taxon
  VL  - 
  IS  - 
  ER  -