Re: AW: SV: avian nomenclature

[evelyn sobielski <koreke77@yahoo.de>]

> 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.

http://www.palaeodiversity.org/pdf/02/Pal_2_15_315-320_gu_sw.pdf

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/2246/2536, 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 
selection/hitchhiking). 

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".


Regards,

Eike

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