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A web-database of mammalian morphology and a reanalysis of placental phylogeny.

Asher RJ - BMC Evol. Biol. (2007)

Bottom Line: The results reinforce the growing consensus regarding the extant placental mammal clades of Afrotheria, Xenarthra, Euarchontoglires, and Laurasiatheria.Depending on treatment of third codon positions, the affinity of several fossils (Leptictis,Paleoparadoxia, Plesiorycteropus and Zalambdalestes) vary, highlighting the potential effect of sequence data on fossils for which such data are missing.Additional morphological data are desirable to better reconstruct the position of several fossil taxa; and the graphic-rich, web-based morphology data matrix presented here will make it easier to incorporate more taxa into a larger data matrix.

View Article: PubMed Central - HTML - PubMed

Affiliation: Museum of Zoology, University of Cambridge, Cambridge, UK.

ABSTRACT

Background: Recent publications concerning the interordinal phylogeny of placental mammals have converged on a common signal, consisting of four major radiations with some ambiguity regarding the placental root. The DNA data with which these relationships have been reconstructed are easily accessible from public databases; access to morphological characters is much more difficult. Here, I present a graphical web-database of morphological characters focusing on placental mammals, in tandem with a combined-data phylogenetic analysis of placental mammal phylogeny.

Results: The results reinforce the growing consensus regarding the extant placental mammal clades of Afrotheria, Xenarthra, Euarchontoglires, and Laurasiatheria. Unweighted parsimony applied to all DNA sequences and insertion-deletion (indel) characters of extant taxa alone support a placental root at murid rodents; combined with morphology this shifts to Afrotheria. Bayesian analyses of morphology, indels, and DNA support both a basal position for Afrotheria and the position of Cretaceous eutherians outside of crown Placentalia. Depending on treatment of third codon positions, the affinity of several fossils (Leptictis,Paleoparadoxia, Plesiorycteropus and Zalambdalestes) vary, highlighting the potential effect of sequence data on fossils for which such data are missing.

Conclusion: The combined dataset supports the location of the placental mammal root at Afrotheria or Xenarthra, not at Erinaceus or rodents. Even a small morphological dataset can have a marked influence on the location of the root in a combined-data analysis. Additional morphological data are desirable to better reconstruct the position of several fossil taxa; and the graphic-rich, web-based morphology data matrix presented here will make it easier to incorporate more taxa into a larger data matrix.

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Optimal MP topologies, third positions removed. Strict consensus of 4 trees (27858 steps) resulting from combined morphology-DNA-indel dataset, excluding third positions from protein-coding genes. Numbers indicate bootstrap support values (only reported above 50); asterisks indicate support of 100. Daggers indicate extinct taxa.
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Figure 2: Optimal MP topologies, third positions removed. Strict consensus of 4 trees (27858 steps) resulting from combined morphology-DNA-indel dataset, excluding third positions from protein-coding genes. Numbers indicate bootstrap support values (only reported above 50); asterisks indicate support of 100. Daggers indicate extinct taxa.

Mentions: The majority of the combined DNA-morphology analyses support the clades Afrotheria, Xenarthra, Euarchontoglires, and Laurasiatheria, as well as the placement of the Tertiary insectivoran-grade mammal Centetodon within Lipotyphla and the two Cretaceous eutherians (Ukhaatherium and Zalambdalestes) outside of Placentalia (Figs. 1, 2, 3). Using MP, the position of the placental root varies. With all data and gaps included and weighted equally (Fig. 1), or with third position transitions removed, it is at the Malagasy lesser hedgehog-tenrec Echinops, within a paraphyletic Afrotheria. A strict consensus in each case leaves the placental base unresolved (Fig. 1A) due to the variable position of Zalambdalestes. With third positions of protein-coding genes removed, it is at Xenarthra followed by Afrotheria with Cretaceous taxa outside of crown Placentalia (Fig. 2). Results from the Bayesian analysis using either living taxa and sequence data alone, or including three fossils (Zalambdalestes, Ukhaatherium, and Centetodon) plus morphology (Fig. 3), places the placental root at Afrotheria followed by Xenarthra. When included, Cretaceous taxa are again reconstructed outside of crown Placentalia.


A web-database of mammalian morphology and a reanalysis of placental phylogeny.

Asher RJ - BMC Evol. Biol. (2007)

Optimal MP topologies, third positions removed. Strict consensus of 4 trees (27858 steps) resulting from combined morphology-DNA-indel dataset, excluding third positions from protein-coding genes. Numbers indicate bootstrap support values (only reported above 50); asterisks indicate support of 100. Daggers indicate extinct taxa.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1941728&req=5

Figure 2: Optimal MP topologies, third positions removed. Strict consensus of 4 trees (27858 steps) resulting from combined morphology-DNA-indel dataset, excluding third positions from protein-coding genes. Numbers indicate bootstrap support values (only reported above 50); asterisks indicate support of 100. Daggers indicate extinct taxa.
Mentions: The majority of the combined DNA-morphology analyses support the clades Afrotheria, Xenarthra, Euarchontoglires, and Laurasiatheria, as well as the placement of the Tertiary insectivoran-grade mammal Centetodon within Lipotyphla and the two Cretaceous eutherians (Ukhaatherium and Zalambdalestes) outside of Placentalia (Figs. 1, 2, 3). Using MP, the position of the placental root varies. With all data and gaps included and weighted equally (Fig. 1), or with third position transitions removed, it is at the Malagasy lesser hedgehog-tenrec Echinops, within a paraphyletic Afrotheria. A strict consensus in each case leaves the placental base unresolved (Fig. 1A) due to the variable position of Zalambdalestes. With third positions of protein-coding genes removed, it is at Xenarthra followed by Afrotheria with Cretaceous taxa outside of crown Placentalia (Fig. 2). Results from the Bayesian analysis using either living taxa and sequence data alone, or including three fossils (Zalambdalestes, Ukhaatherium, and Centetodon) plus morphology (Fig. 3), places the placental root at Afrotheria followed by Xenarthra. When included, Cretaceous taxa are again reconstructed outside of crown Placentalia.

Bottom Line: The results reinforce the growing consensus regarding the extant placental mammal clades of Afrotheria, Xenarthra, Euarchontoglires, and Laurasiatheria.Depending on treatment of third codon positions, the affinity of several fossils (Leptictis,Paleoparadoxia, Plesiorycteropus and Zalambdalestes) vary, highlighting the potential effect of sequence data on fossils for which such data are missing.Additional morphological data are desirable to better reconstruct the position of several fossil taxa; and the graphic-rich, web-based morphology data matrix presented here will make it easier to incorporate more taxa into a larger data matrix.

View Article: PubMed Central - HTML - PubMed

Affiliation: Museum of Zoology, University of Cambridge, Cambridge, UK.

ABSTRACT

Background: Recent publications concerning the interordinal phylogeny of placental mammals have converged on a common signal, consisting of four major radiations with some ambiguity regarding the placental root. The DNA data with which these relationships have been reconstructed are easily accessible from public databases; access to morphological characters is much more difficult. Here, I present a graphical web-database of morphological characters focusing on placental mammals, in tandem with a combined-data phylogenetic analysis of placental mammal phylogeny.

Results: The results reinforce the growing consensus regarding the extant placental mammal clades of Afrotheria, Xenarthra, Euarchontoglires, and Laurasiatheria. Unweighted parsimony applied to all DNA sequences and insertion-deletion (indel) characters of extant taxa alone support a placental root at murid rodents; combined with morphology this shifts to Afrotheria. Bayesian analyses of morphology, indels, and DNA support both a basal position for Afrotheria and the position of Cretaceous eutherians outside of crown Placentalia. Depending on treatment of third codon positions, the affinity of several fossils (Leptictis,Paleoparadoxia, Plesiorycteropus and Zalambdalestes) vary, highlighting the potential effect of sequence data on fossils for which such data are missing.

Conclusion: The combined dataset supports the location of the placental mammal root at Afrotheria or Xenarthra, not at Erinaceus or rodents. Even a small morphological dataset can have a marked influence on the location of the root in a combined-data analysis. Additional morphological data are desirable to better reconstruct the position of several fossil taxa; and the graphic-rich, web-based morphology data matrix presented here will make it easier to incorporate more taxa into a larger data matrix.

Show MeSH