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Re: Mesozoic roots of parrots and passerine birds
My 0.02 € on the "Cretaceous parrot jaw"... anyone designing a
phylogenetic analysis will have to keep in mind that "loriid" and
"oviraptorosaur" aren't the only two possibilities. There are many
Cretaceous clades of toothless birds, and their fossil record is bad
enough that we hardly know anything about their distribution in space
and time or, therefore, their morphological diversity. Off the top of my
head, imaginable candidates for close relatives are the
confuciusornithids (in particular *Changchengornis* with its slightly
hooked beak), so far known _exclusively_ from Konservat-Lagerstätten,
*Gobipteryx*, likewise only known from one site, and *Samrukia*, which
may be closely related to the much smaller *Patagopteryx* (...no, I
don't mean *Patagonykus* this time ;-) ).
The problem is exacerbated by the dating issue. "Eufalconimorphae"
are not entirely unreasonable, but Cretaceous? What about
Close enough to a "missing link" somewhere near the base of
Eufalconimorphae, but alive and kicking after 50 Ma including a
mega-extinction and near-complete ecological turnover (and
carnivorous to boot?) and still very much *looking* like the misssing
link you'd expect? It works too well in some aspects, and it
completely sucks in others. Those parts of the tree we *have*
resolved for good fit together more or less awkwardly, but overall in
a satisfying way.
IMNSHO, the "dating" is bunk; fortunately, it's tacked on to the end of
the study, not an integral part of it, so it can be disregarded without
casting doubt on the other results.
Indeed, as I've already mentioned, I think the phylogenetic tree they
got is itself evidence for much younger dates. That huge unresolved
Neoaves radiation which shows evidence of incomplete lineage sorting
(contradictory distributions of retroposons)? That looks like it happend
very, very quickly. The only time at which I can imagine such a thing
happening is in the empty world after the K-Pg boundary mass extinction.
Thanks a lot for the links. Evidently, somebody has now persuaded the
university library of Vienna to use some of its nonexistent funds to buy
the 2nd-ranked journal in paleontology (impact factor of 2010: 3.844 --
the JVP had 2.241 and is the 8th-ranked journal in paleontology). Excuse
me while I go on a downloading spree that will probably take all week.