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Re: Avian Ancestors, new book on theropods
> Federico L. Agnolín & Fernando E. Novas (2013)
> Avian Ancestors: A Review of the Phylogenetic Relationships of the
> Theropods Unenlagiidae, Microraptoria, Anchiornis and
> SpringerBriefs in Earth System Sciences
> ISBN: 978-94-007-5636-6 (Print) 978-94-007-5637-3 (Online)
> DOI: 10.1007/978-94-007-5637-3_3
> The front and back matter is apparently free but the links are not
> working at present. The first few pages of the content of each chapter
> can be previewed by clicking on the "Look Inside" icon.
It appears the authors regard Deinonychosauria as paraphyletic, with
troodontids (excluding _Anchiornis_ and _Xiaotingia_) and
dromaeosaurids as successive outgroups (Fig. 2.1). Dromaeosauridae is
also found to be paraphyletic, with microraptorans and unenlagiids
located more crownward than dromaeosaurids.
The new name Averaptora is erected for a Microraptoria + (Unenlagiidae
+ ((_Anchiornis_ + _Xiaotingia_) + Avialae)) clade. (_Rahonavis_ is
an avialan here, not a unenlagiid.) In keeping with a paraphyletic
Deinonychosauria, Paraves and Eumaniraptora no longer have the same
content: Paraves is defined as all maniraptorans closer to crown Aves
than to _Oviraptor_; and Eumaniraptora is defined as all taxa closer
to _Passer_ than to _Troodon_.
I'm not sure the new name Averaptora is essential. Zhang et al.
(2008) previously defined Avialae as the most inclusive clade
including crown birds but not dromaeosaurids (specified by
_Deinonychus_). So their Avialae is equivalent in content to Agnolin
and Novas' new clade Averaptora.
Agnolin and Novas' instead use Avialae for the _Archaeopteryx_ + crown
bird clade. In view of all the unstable position of _Archaeopteryx_,
I think it makes sense to use Avialae as a stem clade that includes
crown birds but excludes dromaeosaurids, and cease using
_Archaeopteryx_ as a specifier. Personally, I like Martyniuk's (2012)
proposed new clade Ornithes for the _Archaeopteryx_ + crown bird
clade, although I doubt it will catch on.