Housekeeping the bird subset of the LRT, part 2

Updated several days later,
here in part 3, with more insights and changes to the bird cladogram.

Short one today after another weekend binge learning
more about the birds in the large reptile tree (LRT, 1865+ taxa; subset Fig. 1).

Figure 1. Updated subset of the LRT focusing on crown birds. Colors indicate general body size and niche. Basal birds show a pattern of long, wading legs. Short leg taxa evolve from them by convergence, likely via paedomorphosis because the chicks of long-legged adults have much shorter legs.

The present topology
(Fig. 1) settles some earlier issues and brings forth an interesting not-quite-overlooked relationship between the prehistoric long-legged duck, Presbyornis (Fig. 2) and the giant extant shoebill stork, Balaeniceps (also iin Fig. 2).

Figure 2. The extant shoebill stork, Balaeniceps, is much larger than the early Eocene duck ancestor, Presbyornis, but shares similar proportions.

The long-legged, extant hamerkop
(Scopus umbretta, Fig. 3)) now nests close to African hornbills (Buceros) and South American toucans (Pteroglossus). That means it must have existed before the appearance of the South Atlantic and the splitting of those two contents, 100 mya, a topic we looked at earlier here.

Figure 4. Scopus, the hammerkop, in vivo.
Figure 4. Scopus, the hammerkop, in vivo.

The hamerkop also nests basal to
Presbyornis and Balaeniceps (Fig. 2) on a separate branch. So, you can talk about this taxon being a ‘living fossil’ if you want to. It’s amazing how many taxa remain unchanged since the middle of the Cretaceous, 100 mya..

The LRT is never done.
And the LRT is never perfect. A review of purported sisters should demonstrate a gradual accumulation of derived traits. Today’s corrections improve on prior attempts toward that goal. There is no phenomic bird evolution textbook to learn bird evolution, so some things. like this, you have to learn for yourself.

Thank you for your readership.

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