NEORNITHINE PHYLOGENY etc

[<darren.naish@port.ac.uk>]

The following just in. Some of them pretty important from my biased
perspective.

Gardner, J. D. 2001. Monophyly and affinities of albanerpetonid
amphibians (Temnospondyli; Lissamphibia). _Zoological J. Linnean
Society_ 131, 309-352.

Latest in a series of papers resulting from Gardner's phd work. This
paper definitively refutes arguments that albanerpetonids are caudates
and provides much support for the view that they are the sister-taxon to
Caudata + Salientia. Use of 'Temnospondyli' here is a reference to
Temnospondyli sensu Gauthier et al., obviously. Lot of stuff on cranial
features in albanerpetonids indicative of a shearing bite; also
adaptations for burrowing.

Galis, F. 2001. Digit identity and digit number: indirect support for the
descent of birds from theropod dinosaurs. _Trends in Ecology and
Evolution_ 16, 16.

It would seem a little debate on digit homology has been going on in
the pages of TREE, and this is the article that started it all.
Drossopoulou et al. (2000, _Development_ 127: 1337-1348) showed
that manipulation of the Sonic hedgehog gene resulted in embryos with
the same number of digits BUT with different digit identities. Inspired,
Galis suggested that this offered support for Wagner and Gauthier's
model of homeotic change producing the conflict in avian digit
identities. Galis' article prompted the response....

Feduccia, A. 2001. Digit homology of birds and dinosaurs:
accommodating the cladogram. _TREE_ 16, 285-6.

Feduccia basically restated the evidence presented in Burke and
Feduccia (1997) that the first digit to condense along the primary axis
MUST be digit IV. While Drossopoulou et al. showed that a homeotic
shift *could* occur, the point, according to Feduccia, is: 'whether it
did occur'. Feduccia goes on to argue that palaeontologists are
distorting things in order to 'accomodate the cladogram'. Feduccia's
article prompted the response....

Galis, F. 2001. Digit homology of birds and dinosaurs: accomodating
the cladogram. Response to Feduccia. _TREE_ 16, 286.

To cut a long story short, evidence from the embryology of extant birds
indicates that a homeotic change in digit identity >did< occur: Galis
cites multiple studies which, it is argued, support this view. I can't do
this case justice without going into intricate detail, and I'm not about
to do that.

Carrano, M. T. 2001. Implications of limb bone scaling, curvature and
eccentricity in mammals and non-avian dinosaurs. _J. Zoology_ 254,
41-55.

A lot of stuff here, highlighting both differences and similarities seen
between mammal and dinosaur limb bones.

Haddrath, O. and Baker, A. J. 2001. Complete mitochondrial DNA
genome sequences of extinct virds: ratite phylogenetics and the
vicariance biogeography hypothesis. _Proc. R. Soc. Lond. B_ 268,
939-945.

Analysis of the data, which includes DNA sequences from two moa
species, supports ratite monophyly and a basal position for moa (but,
as is virtually always the case for DNA studies, with kiwis grouping
with casuariforms and not with moa). In terms of biogeography, this
result means that both kiwis and ostriches diverged too recently for
their distributions to be explained by vicariance (but read the paper,
there is more to it than this).

Cracraft, J. 2001. Avian evolution, Gondwana biogeography and the
Cretaceous-Tertiary mass extinction event. _Proc. R. Soc. Lond. B_
268, 459-469.

This paper is a must-have for those interested in Gondwanan origins of
neornithines, or in the interrelations of neornithines. Analysis and
collation of phylogenetic data for neornithines indicate a strong trans-
Antarctic distribution for basal members of all neornithine clades:
Cracraft looked at palaeognaths (all 8 analysed clades likely trans-
Antarctic), galloanseraens (all 7 analysed clades except anatids likely
trans-Antarctic), gruiforms (all 13 analysed clades except turnicids,
otidids, gruids and rallids likely trans-Antarctic), caprimulgiforms and
apodiforms (all 7 analysed clades except caprimulgids and apodids
likely trans-Antarctic) and passerines (all 7 analysed clades except
passeridans likely trans-Antarctic). Thus there is a strong trans-
Antarctic signal for neornithines.

Cracraft takes issue with claims of northern origin for some taxa (e.g.,
steatornithids and podargids) restricted today to the south, many of
them made by Olson and Feduccia. The data also indicates that
neornithine diversification was underway before the end of the
Cretaceous, thus Cracraft agrees with, e.g., Cooper and Penny's results
and not with Feduccia's post-KT explosion model (the 'Tertiary
radiation hypothesis'). Aspects of the neornithine tree favoured by
Feduccia and Olson (e.g., presbyornithids as transitional between
anseriforms, charadriiforms and phoenicopteriforms) are also rejected
and there are a few stabs at Feduccia and co for rejecting cladistic
analysis when it does not support a favoured view on relationships. It
always strikes me that, whereas many people interested in non-avian
dinosaurs know much about Feduccia and Olson's claims regarding
bird ancestry, few are aware that these workers also maintain very
controversial viewpoints on the phylogeny of neornithines, the areas in
which they do at least have great first hand experience. This paper is
thus a definitive response to claims made by Feduccia and co in recent
works. Cracraft cites as in press the following...

Cracraft, J. and Clarke, J. 2001. The basal clades of modern birds.
_Bull. Peabody Mus. Yale Univ._.

I look fwd to it.

DARREN NAISH
PALAEOBIOLOGY RESEARCH GROUP
School of Earth & Environmental Sciences
UNIVERSITY OF PORTSMOUTH
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