A new volume published by the AMNH
(eds. Pittman and Xu 2020), is all about the the putative clade, ‘Pennaraptora’ (Fig. 1). According to the preface, “Pennaraptora comprises birds themselves as well as the pennaceous feathered dromaeosaurids, troodontids, scansoriopterygids, and oviraptorosaurians.”
in the large reptile tree (LRT, 1727+ taxa; subset Fig. 2) scansoriopterygids are birds, not oviraptorosaurian sisters. Oviraptorosaurians are terminal taxa in a larger clade that includes therizinosaurs and the CNJ79 specimen of Compsognathus and that clade is the sister clade of the Compsognathus holotype, struthiomimids and tyrannosaurids (Fig. 2). The last common ancestor of all these clades in the LRT is Aorun zhaoi (Choiniere et al. 2013; IVPP V15709, Late Jurassic 161mya).
So this multipart study on ‘Pennaraptorans’ is off to several bad starts. Neither ‘Aorun‘, nor ‘Tyrannoraptora’ (see below) are mentioned in the text. Several taxa have been omitted from this clade, including the last common ancestor.
Only two generic taxa and “their last common ancestor (LCA)”
should be enough to define a clade. Look what bad things can happen when you use four suprageneric taxa (Fig. 1). Don’t let in generic taxa that do not belong and omit generic taxa that do belong. Even so, and surprisingly, all taxa employed here are clade members. Unfortunately the clades and a few taxa are a little mixed up due to taxon exclusion.
Foth et al. defined Pennaraptora in 2014.
“Pennaraptora is a clade defined as the most recent common ancestor of Oviraptor philoceratops, Deinonychus antirrhopus, and Passer domesticus (the house sparrow), and all descendants thereof,” Again, this definition only needs the first two taxa. Passer nests within “all descendants thereof”. Even so, this is a definition we can work with (Fig. 2).
In the LRT ‘Pennaraptora’
is almost a junior synonym of Compsognathidae (Cope 1871; Fig. 2) because two specimens of Compsognathus are basalmost taxa. However, Aorun is the last common ancestor taxon. It was originally considered the oldest known coelurosaurian theropod and a juvenile.
According to Wikipedia, Aorun is now considered a member of
the Tyrannoraptora (Sereno 1999) defined as, “Tyrannosaurus, Passer their last common ancestor [Aorun] and all of its descendants.” So Pennaraptora (2014) is a junior synonym of Tyrannoraptora (1999). The two define the same clade in the LRT and share a last common ancestor.
Coelurosauria (von Huene 1914 is defined as theropods closer to birds than to carnosaurs. In the LRT Tyrannoraptora is also a junior synonym for Coelurosauria.
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