Traditional cladograms include
only one Solnhofen bird, typically labeled Archaeopteryx. Whether they use the holotype specimen or not, I don’t know. Earlier the large reptile tree (LRT, subsets Figs. 1, 2) added several Solnhofen birds, many workers continue to call Archaeopteryx, while others have given new generic names. A recent paper by Wang and O’Connor 2017 on pygostyles brought this subject back to the table. They recovered four different sorts of pygostyles, but did not recognize four convergent origins for the pygostyles due to (I thought at the time) lacking more than one Archaeopteryx specimen. It’s time to test that assertion.
As reconstructions show
the variety of Solnhofen birds has been largely, but not completely overlooked. In any case the variety is certainly apparent and a revision of the genus Archaeopteryx is long overdue given the interest in every new specimen.
So, what happens to the LRT when only one Archaeopteryx (the holotype) is employed?
< See figure 1.
There is no change in the tree topology, other than the loss of six Solnhofen bird taxa (Fig. 2). The holotype Archaeopteryx continues to nest within Enantiornithes, an extinct bird clade.
Taxon deletion is a good test
Having seven Solnhofen birds
in a cladogram illuminates the origin of birds, the origin of enantiornitine birds, the origin of scansoriopterygid birds and the origin of ornithuromorph birds all from Late Jurassic Solnhofen taxa, something we haven’t had until this point. This is what Wang and O’Connor 2017 lacked and so their report on pygostyles was unnecessarily incomplete.
I encourage all bird workers
to include as many Solnhofen birds as possible in their phylogenetic analyses, and for at least one of them (hopefully more) to revise their taxonomy to include more genera. That would make a great PhD thesis.
Wang W and O’Connor JK 2017. Morphological coevolution of the pygostyle and tail feathers in Early Cretaceous birds. Vertebrata PalAsiatica 2017:10: 55:3: 1-26.