FW: likelyhood for these avian clades?

[Christopher Taylor <ck.taylor@auckland.ac.nz>]

Cathartidae (Ciconiidae (Scopidae (Balaenicipitidae + Steganopodes)...

    To complete this, Procellariiformes, should be in there somewhere,
perhaps as sister to Scopidae (Balaenicipitidae + Steganopodes). The main
reference for this, I believe, is Mayr (2003). Mayr & Clarke (2003) found
quite different positions for the taxa in question, but in the phylogenetic
analysis in that paper where none of the characters are ordered, almost all
the relevant branches disappear into the massive basal polytomy.
    Most papers on neornithine phylogeny these days seem to recognise a
clade composed of Pelecaniformes, Procellariiformes, _Gavia_, Spheniscidae
and at least some 'Ciconiiformes' (in the older, more restricted sense, not
in Sibley & Ahlquist's (1990) much more extensive sense). Within this,
Procellariiformes, _Gavia_ and Spheniscidae form a well-supported clade.
Sibley & Ahlquist (1990) used the name Procellarioidea for the clade
containing these groups plus Fregatidae, and for convenience I'll shanghai
that name for the clade of these groups alone.
    Mayr (2003) found the following characters to support Scopidae through
to Steganopodes:
    - premaxilla (upper beak) with sharply hooked tip (secondarily lost in
Sulidae and _Anhinga_)
    - premaxilla with marked furrow distal of nasal opening (secondarily
lost in _Anhinga_)
    - ossified septum nasale
    - ossa palatina fused along midline
    - extremitas omalis of furcula with strongly developed, laterally
protruding facies articularis acrocoracoidea (maybe lost in _Fregata_)
    - dorsal surface of sternum with numerous pneumatic foramina along
midline and lateral margins
    - hypotarsus of tarsometatarsus with tendon of musculus flexor digitorum
longus and m. flexor hallucis longus enclosed in bony canal (canal for m.
flexor digitorum longus only _Fregata_, canal reduced to groove in
Phalacrocoracidae)
    - musculus expansor secondariorum vestigial or absent (also in
_Phaethon_)
    - eggshell covered with layer of microglobular calcium carbonate (also
in Ardeidae and Spheniscidae)

    Balaenicipitidae + Steganopodes was supported by two characters:
    - external narial openings greatly reduced or albsent
    - furcula with apophysis furculae abutting with an articular facet at
the apex carinae of carina sterni.

    The most interesting point about the characters uniting Scopidae,
Balaenicipitidae and Steganopodes is the absence of most of them from
_Phaethon_, usually united with Steganopodes in the 'Pelecaniformes'. In
molecular studies, _Phaethon_ actually comes up as closely related to the
Suloidea, for instance in van Tuinen et al. (2001). Pelcaniformes is
traditionally united by two major characters, the reversed hallux with
inclusion of all four toes in the webbed foot, and a gular pouch. The gular
pouch is feathered in _Phaethon_ vs. naked in Steganopodes, and apparently
some have doubted if _Phaethon_'s pouch is even really there. The web
connecting the reversed hallux is very small in _Phaethon_, and barely there
in _Fregata_. A small web also connects the hallux to the other toes in
Spheniscidae. Mayr implied in passing that _Phaethon_ might be sister to
Procellarioidea, but only as a subject for later investigation.
    The position of _Fregata_ relative to other 'Pelecaniformes' is also
difficult. As noted before, Sibley & Ahlquist (1990) included it in
Procellarioidea, as sister to all the other members. Hedges & Sibley (1994)
even found it as sister to Cathartidae. However, Hedges & Sibley used a
method of testing tree support that wildly overestimated such support, and
when bootstrapped or jack-knifed their tree mostly collapses to a polytomy.
    I can't say too much about the suggested position of Cathartidae
mentioned. Sibley & Ahlquist (1990) found Cathartidae to be very closely
related to Ciconiidae, and gave a long summary of older morphological
investigations suggesting the same thing. Has an analysis ever been
published which specifically shows the relationships suggested here, or is
it a compromise position to reconcile the different views of ciconiid
relationships?

    Cheers,

        Christopher Taylor

On 21/5/04 4:58 am, "Brian Lauret" <zthemanvirus@hotmail.com> wrote:

> There are a certain number of clades I've seen proposed on the net and I
> wondered if these are really likely, or perhaps likely in a somewhat altered
> form:
> 
> clade (Psophiidae(Cariamidae(Opistocomidae(Musophagidae))))
> clade (Cathartidae(Ciconiidae(Scopidae(Balaenicipitidae(Steganopodes)))))
> clade (Staethornithidae(Trogonidae))
> 
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