Psittacopasserae

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Psittacopasserans
Temporal range: Eocene - Holocene, 55–0Ma
House Sparrow mar08.jpg
House sparrow, Passer domesticus
Psittacus erithacus -perching on tray-8d.jpg
African grey parrot, Psittacus erithacus
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Clade: Eufalconimorphae
Clade: Psittacopasserae
Suh et al., 2011
Orders

Passeriformes
Psittaciformes

Psittacopasserae is a taxon of birds consisting of the Passeriformes (passerines, a large group of perching birds) and Psittaciformes (parrots). Originally proposed following an alignment of nuclear intron sequences by Shannon Hackett et al. in 2008,[1] it was formally named in a 2011 Nature Communications article by Alexander Suh and other authors working with Jürgen Schmitz's group,[2] based on genetic analysis of the insertion of retroposons into the genomes of key avian lineages over the course of evolution during the Mesozoic Era.

The (possible) alternative names for this group are Psittacimorphae (Huxley, 1867) and/or Passerimorphae (Sibley et al., 1988) though more likely the former would be correct as the latter incorporated other avian orders that are now discarded to be close relatives to songbirds.

Technical considerations[edit]

Analysis of retroposon insertions offers a higher degree of confidence because retroposon insertion is "virtually homoplasy-free", as retroposons insert at random positions throughout the genome, whereas point mutations in DNA cycle between only four possible options. This makes it less likely that random coincidence or convergent evolution creates illusory similarities between unrelated groups. However, the technique requires very extensive genomic data - in the 2011 paper, approximately 200,000 retroposon-containing loci were examined to identify 51 individual retroposition events which are present in some birds but not others.

Significance in the evolution of birdsong[edit]

Passerines are renowned as songbirds, and parrots share a capacity for vocal learning. Thus it is possible that vocal learning, and the corresponding variety of song, was present in a psittacopasseran ancestor.[2]

References[edit]

  1. ^ Shannon J. Hackett et al. (2008-06-07). "A Phylogenomic Study of Birds Reveals Their Evolutionary History". Science 320 (5884): 1763–1768. doi:10.1126/science.1157704. PMID 18583609. 
  2. ^ a b Alexander Suh et al. (2011-08-23). "Mesozoic retroposons reveal parrots as the closest living relatives of passerine birds". Nature Communications 2 (8). doi:10.1038/ncomms1448. PMC 3265382. PMID 21863010.