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Re: [dinosaur] Confuciusornis cranial morphology

It's certainly an intriguing paper.  Confuciusornithid maxillae never did make much sense, so their identification of the supposed maxillary fenestra as a nasolacrimal foramen looks solid.  Ditto their taphonomic explanation for the weird robust postorbital processes in some specimens.  I think it's interesting to see the perspective of Mayr who normally works with fossils of crown Aves, compared to Chiappe and Norell who are experts in stem Aves.  Then there's Elzanowski, who in the late nineties and early 2000s interpreted Archaeopteryx's cranial anatomy as quite autapomorphic, only to be reinterpreted by Rauhut (2013; et al., 2018) as traditionally theropodan.  So is Confuciusornis this autapomorphic, with supraorbitals, a fused ethmoidolacrimal, and a postorbital process that's largely just expansions of surrounding bones?  And would other basal birds be this way if we examined them past their initial brief descriptions?

Mickey Mortimer

From: dinosaur-l-request@usc.edu <dinosaur-l-request@usc.edu> on behalf of Tim Williams <tijawi@gmail.com>
Sent: Monday, April 9, 2018 10:07 PM
To: dinosaur-l@usc.edu
Subject: Re: [dinosaur] Confuciusornis cranial morphology
Sally-striking foraging behavior fits with the aspect ratio of
_Confuciusornis_ wings.  Wide, broad wings confer high maneuverability
(Falk et al. 2016 doi.org/10.1371/journal.pone.0167284), which would
be essential for snatching flying insects out of the air.  As
Elzanowski &c note, sally-strikes could be launched from either the
ground or an arboreal perch.  However, contra Elzanowski &c, it would
not have been necessary for _Confuciusornis_ to climb trees in order
to reach a perch, given the likelihood that it could take off from the
ground (e.g. Dececchi & Larsson 2011
doi:10.1371/journal.pone.0022292).  In any case, the manus of
_Confuciusornis_ was highly unsuitable for tree-climbing (e.g., Peters
& Ji 1999 J.Ornithol. 140:41-50; Chiappe et al. 1999 Bull. AMNH
242:1-89, etc).

On Tue, Apr 10, 2018 at 7:36 AM, Ben Creisler <bcreisler@gmail.com> wrote:
> Ben Creisler
> bcreisler@gmail.com
> A new paper:
> Andrzej Elzanowski, D. Stefan Peters & Gerald Mayr (2018)
> Cranial morphology of the Early Cretaceous bird Confuciusornis.
> Journal of Vertebrate Paleontology Article: e1439832
> DOI: 10.1080/02724634.2018.1439832.
> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.tandfonline.com_doi_full_10.1080_02724634.2018.1439832&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=0GAJyNuAp8oHra3hqdHqNpJl8L-7SHAgb_DTdw9v5eo&s=AgQvJi_TyDDRlkUSyT-CPiQJURTlGMxaBkGFiwk0UbU&e=
> Confuciusornis sanctus has been heralded as a bird with an ancestrally
> diapsid skull, although this does not match its phylogenetic position as
> determined by other skeletal features. Based on 13 cranial specimens in
> European collections, we demonstrate that the observed scaffolding in the
> temporal region is highly derived and comparable to some of 21–23 cases of
> secondary bridges across the temporal fossa that evolved in modern birds. In
> Confuciusornis, the temporal fossa is crossed by a secondary temporal bar
> (absent in Eoconfuciusornis) that is continuous with the braincase but
> discontinuous with the postorbital process. A small postorbital bone (if
> present) is covered by this secondary ossification. The postorbital process
> is continuous with a prominent supraorbital rim and extends to the jugal as
> in sally-striking birds, including some Podargidae (Podargus), Leptosomidae,
> Brachypteraciidae, Coraciidae, Bucconidae, and Galbulidae, which tend to
> have wide gapes, large jaws with deep cranial rostra (and the nasal opening
> in a caudal position), and require additional attachments of musculus
> adductor mandibulae externus for fast and powerful snatching of the prey.
> The best modern analogue for the secondary temporal scaffolding seen in
> Confuciusornis is provided by Podargus, in which the long postorbital
> process is propped up by the temporal bar in addition the secondary bridge
> across the temporal fossa. The cranial evidence identifies Confuciusornis
> sanctus as a sally-striking predator.
> ================