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RE: Our current understanding of Mesozoic bird phylogeny

> Interesting.  A Confuciusornithidae+Enantiornithes
> clade would explain the 
> similar hallucal morphology between
> confuciusornithids and certain 
> enantiornitheans (like _Concornis_ and _Sinornis_). 
> In all these taxa, the 
> hallux is medially/posteromedially oriented to form
> an incipiently or weakly 
> perching foot.  Avisaurids show a more advanced
> condition, presumably 
> derived from this; while the perching foot of
> ornithuromorphs evolved 
> independently.

What about _Yungavolucris_? The specimen does not look
like it walked a lot but IIRC it's neither too well
adapted for perching. Is there anything Mesozoic
around which has similar proportions? (Is there
*anything* with similar proportions?)

Crown avisaurids -> functional convergence to gripping
feet of Falconiformes maybe?

> Good call, the position of Lectavis differed as
> well.  Upon rerunning the 
> analysis with a few modifications, Lectavis was back
> inside Enantiornithes, 
> though barely.  This is based on four characters-
> tibiotarsal distal 
> condyles equal in anterior projection (absent in
> Sazavis; unknown in 
> Aberratiodontus); plantar surface of metatarsus
> excavated (absent in 
> Yungavolucris and Gobipteryx; also in Confuciusornis
> and Patagopteryx; 
> unknown in Aberratiodontus); tubercle on midshaft of
> metatarsal II (also in 
> Confuciusornis and Yanornis+Passer; unknown in
> Aberratiodontus); metatarsal 
> IV much narrower than II and III (absent in
> Iberomesornis and 
> Liaoningornis+Vorona).
> As you can imagine, a position in
> Confuciusornithidae isn't many steps 
> longer (as there are no ornithothoracine hindlimb
> characters known / 
> included), nor is a position in basal Euornithes 
> (especially since Lectavis 
> has a hypotarsus, otherwise only present in
> euornithines).

Mmmh, it certainly would expand confuciornithine
diversity to a point where one would have to assume
the fossil record to be VERY imperfect/misassigned
and/or _Confuciusornis_ itself to be a crown member of
its clade (which could push back the latter's origin
to a point where things would get really interesting
and/or ugly).

Geography suggests against it though, or else
ocean-crossing ability would have been present before
the full mobility of the shoulder girdle evolved (it
was not yet present in _Confuciusornis_, preventing an
effective, modern-bird-type recovery stroke).

And then there is the question of size - if Lectavis
was simply scaled up, the issue of whether it wasn't
actually flightless arises. But it seems to have been
long-legged rather than big - and this, in turn, would
suggest a cursorial lifestyle, meaning that the
hypotarsus (which certainly is an autapomorphy as
regards to other avian hypotarsi) might have high
adaptational value and thus be of limited phylogenetic

(Given the fact that the trochleae are missing, it
could be possble, with not too much deliberate ill
character choice, to achieve a
clade. This could then go party with the "monophyletic
foot-propelled divers" clade
Hesperornis+Gavia+Podiceps ;-P )

* Useful insofar as to set it apart from the other
Lecho Fm. taxa, which certainly is a most welcome
find. Indeed, Walker's infamous "New Subclass" paper
uses the diverse morphology of the El Brete material
to argue for the Enantiornithes being a major and
diverse lineage, which is certainly correct.

Many thanks for the work (finally we seem to be
getting *somewhere* as regards Enantiornithes internal


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