Bird evolution: testing the Metaves clade with six new mitochondrial genomes

Area of Science:

• Avian evolution
• Molecular phylogenetics
• Genomics

Background:

• Morphological convergence can mislead evolutionary studies of birds.
• Molecular data, especially short DNA sequences, also present phylogenetic challenges.
• The evolutionary relationships and timing within modern birds (Neoaves) remain incompletely resolved.

Purpose of the Study:

• To test the proposed Metaves/Coronaves division within Neoaves using new mitochondrial genome data.
• To investigate parallel radiations within this primary avian clade.
• To resolve contentious evidence of morphological convergence.

Main Methods:

• Phylogenetic analysis of six new bird mitochondrial genomes (hummingbird, swift, kagu, rail, flamingo, grebe).
• Inclusion of data from 41 avian mitochondrial genomes (13,229 bp).
• Application of a novel site-stripping technique for noise reduction in phylogenetic analysis.

Main Results:

• Mitochondrial trees did not support the Metaves clade, suggesting artifacts from indels in nuclear intron data.
• Flamingos and grebes are identified as sister taxa, basal to shorebirds (Charadriiformes).
• The hummingbird/swift clade is positioned outside the diverse group of raptors, shorebirds, and seabirds; kagu and rail relationships remain unresolved.

Conclusions:

• The phylogenetic hypothesis based on 41 avian mitochondrial genomes rejects the monophyly of seven Metaves species.
• Members of the proposed Metaves clade do not share a common evolutionary history within Neoaves.
• This study refines our understanding of avian evolutionary relationships and highlights limitations of previous analyses.