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Re: AW: SV: avian nomenclature
> Speaking of Mayr, two recent papers of his are worth
> looking at in the context of bird phylogenetics:
> Mayr, G. (2009). A well-preserved skull of the
> "falconiform" bird _Masillaraptor_ from the middle Eocene of
> Messel (Germany). Palaeodiversity 2: 315â320.
> Mayr, G. (2009). Phylogenetic relationships of the
> paraphyletic 'caprimulgiform' birds (nightjars and allies).
> J Zool Syst Evol Res doi: 10.1111/j.1439-0469.2009.00552.x
> The first paper avoids any firm conclusions regarding the
> affinities of the Eocene raptorial bird _Masillaraptor_,
> because of the polyphyletic nature of Falconiformes.Â
> However, call me old-fashioned, but I'm willing to believe
> that Falconiformes (Cathartidae, Sagittariidae, Pandionidae,
> Accipitridae, Falconidae) might be monophyletic after all
> (despite what the molecular analyses say) as supported by
> some morphological analyses.
The question is: para- or polyphyletic? No wonder Mayr's very careful here. He
knows - better than anyone else in the world - that "his" _Masillaraptor_ is
presently *the* key taxon pertaining to the question of "Falconiformes" -phyly,
and from what I have seen from his work, he is anything but a Chatterjeeish
person. And he knows that anything is speculative until somebody takes this
http://digitallibrary.amnh.org/dspace/handle/2246/2598 and this
http://digitallibrary.amnh.org/dspace/handle/2246/2658 and cladistically
reanalyzes the taxa discussed there.
Because it may just be that the "Cariamae" (= today's "Cariamiformes") is all
that is needed to make the traditional Falconiformes monophyletic. Though the
courol ("cuckoo-roller") also needs to be considered, in particular as
_Plesiocathartes_ is now placed there fide Mayr. Which makes the courol lineage
"N Atlantic" in origin, with the present Malagasy distribution relictual.
If a reanalysis of the Science data minus the offending sequence still yields a
polyphyletic "Falconiformes", then this seems good - until a good reanalysis of
the fossil record robustly suggests otherwise at least. And until the effect of
the karyotype rearrangements widely found among "Accipitriformes" is analyzed
(chromosomal rearrangement is liable to have strong consequences for background
But at present, this one intron seems to distort the results to an unknown but
significant amount - its signal is as strong as it is apparently bogus, so
strong in fact that it tends to inordinately overwhelm more robust data:
compare doi:10.1098/rsbl.2006.0523 and doi:10.1186/1471-2148-8-20.
That being said, *if* seriemas (and perhaps leptosomids) are closer to falcons
than anything else is - and it is fair enough to assume so at present -, for
one thing the American-European cariamid+allies lineage provides a geographic
link between the falcon- and the hawk-lineage - the former is American in
origin, the latter European, but the most basal falcons - caracaras - are
nonetheless Neotropical. Pushed south by accipitrids? Who knows.
For another thing, the "molecular" scenario does not agree very well with the
fossil record. Neither in distribution - it advocates an origin of the
falcon/seriema lineage in the Australian region, and a spread via Antarctica
and South America. But there are far, far too many seriema relatives in
Laurasia! Nor in niche - seriemas+allies stick out like a sore thumb in a
"clade" that - being otherwise composed of parrots and passerines, with
woodpeckers&barbets/toucans, maybe trogons and/or mousebirds too, the probable
immediate outgroup - had as its LCA almost certainly a smallish tree-dweller.
In summary, the available evidence agrees best with a "transatlantic" Laurasian
origin for a "largely traditional" Falconiformes, with the falcon/seriema
branch starting diversification in NAmerica, spreading mainly south initially,
and the osprey/secretary/hawk branch in Europe, spreading mainly east and south
initially. Time of origin would be right about the K-Pg boundary in all
probability. The LCA would have been a mid-sized - probably a bit on the larger
side - mesocarnivore with some perching ability but utilizing terrestrial food
sources. Possibly somehow affiliated with limnic habitat - the notion that NW
vultures are actually a "missing link" between falcons/seriemas/hawks and the
freshwater "higher waterbirds" (and Gruiformes proper?) would explain a lot of
puzzling data very nicely.
There have been some (J.Morphol. IIRC) studies on tarsometatarsus and skull
anatomy in traditional "Falconiformes" recently. They simply assumed monophyly
in a falcon-vs-hawk comparison and though no phylogenetic analysis was
undertaken, the fact that they could get away with the assumption of monophyly
very well - that they found a lot of apparent synapomorphies - does not agree
very well with the assumption that there is a vast evolutionary distance
between falcons and hawks.
That being said, a falcon-parrot-passerine clade would still be far less
surprising than other combinations. After all, the "near passerines" have
almost all a strongly apomorphic metatarsal anatomy. In most cases, this
translates to variant -dactyly. In passerines, perching adaptations. In
Coraciiformes proper, digit loss/fusion.
Just like the group analyzed in the second Mayr paper contains a conspicuously
high proportion of taxa able to go into deep cold-induced torpor, and indeed
contains essentially *all* living birds that retain the ability to go
heterothermal even as adults for prolonged periods of time.
In my blatantly neontology-biased view, the discovery that traits that seem
interesting but phylogenetically uninformative turn out to be autapomorphies
after all is which makes this all very interesting. Another case - not fully
studied, but there are some "teaser" papers: either the "seabird" branch of
"higher waterbirds", or even the Neoaves (with most of them losing it again)
may have a telomerase activity that does *not* diminish with age. But here,
more research is necessary because it is increasingly looking like "shrinking
telomeres" are more of a consequence than a cause of senescence...
It is indeed so: "Nothing in biology makes sense except
in the light of evolution" - and "Nothing in evolution makes sense except in
the light of phylogeny".
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