An exercise in DGS today
(digital graphic segregation, Fig. 1). It’s okay to increase the contrast in a fossil photo. That’s not considered ‘manipulating’ the data, but enhancing it, like using a magnifying glass of a colored filter.
Chiappeavis magnapremaxillo (O’Connor et al. 2016, Early Cretaceous; Figs. 1-2) is a basal enantiornithine bird with a pygostyle. The short tail was tipped with a fan of feathers. The forelimbs were relatively larger than in related taxa.
Earlier I nested Chiappeavis between the Eichstaett specimen of Archaeopteryx recurva and Jianianhualong, the large troodontid-like, flightless bird of the Early Cretaceous. Then a red flag appeared. The problem was: short-tailed Chiappeavis did not belong between two long-tailed taxa. That has been repaired in the large reptile tree (LRT) and Chiappeavis has been nested appropriately as it was originally nested by O’Connor et al., with Pengornis (Fig. 2). And now there is no intervening short-tailed taxon between the small Archaeopteryx and the large Jianianhualong, both with long tails.
The first Big Bird
was Jianianhualong. Larger than its closest kin and definitely flightless, Jianianhualong retained asymmetrical flight feathers. It also had a coracoid nearly identical to that found in Sapeornis (Fig. 4). Jianianhualong had a reduced vestige of the large perching pedal digit 1 found in basal volant birds.
The cladogram of birds
has been updated with the addition of taxa (Fig. 5).
O’Connor JK, Wang X-L, Zheng X-T, Hu H, Zhang X-M and Zhou Z 2016.
An Enantiornithine with a Fan-Shaped Tail, and the Evolution of the Rectricial Complex in Early Birds.Current Biology (advance online publication) DOI: http://dx.doi.org/10.1016/j.cub.2015.11.036