Re: likelyhood for these avian clades?

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

    Steatornithidae + Trogonidae was suggested in Mayr (2003) on the basis
of osteological characters, and remained supported after the addition of
more taxa in Mayr and Clarke (2003). Characters supporting this were:
    - Columella with large, hollow, bulbous basal and footplate area with
large fenestra on one side
    - Skull with distinct naso-frontal hinge
    - Distal end of humerus with deep and sharply delimited fossa musculi
brachialis
    - Os carpi ulnare with crus longum much longer than crus breve
    - Pelvis very wide

    _Steatornis_  and Trogonidae are also connected by a number of plumage
characters, such as rictal bristles at the base of the beak.
    Mayr (2003) demonstrated from literature review that the inclusion of
Trogonidae in 'Coraciiformes' (more specifically with Alcediniformes) that
was (supposedly) found by DNA-DNA hybridisation has not been much supported
by later molecular studies. Morphologically, an alcediniform-trogonid
connection was supposed to be supported by:
    - Columella and naso-frontal hinge in skull as above
    - Feet syndactyl (third and fourth toe partly coalescent)

    However, the second toe is also coalescent with the third for most of
its length in the Alcedinidae, while it is turned to point backwards in the
Trogonidae. Mayr argued that the great difference between these conditions
made a connection between the two families unlikely.
    On the whole, a Trogonidae (feeding on the wing, partly frugivorous) +
_Steatornis_ (feeding on the wing, frugivorous) clade is worth keeping as a
possibility, but not yet definite. Such a relationship is interesting from
an ecological perspective, as the nocturnal Caprimulgiformes would then have
twice given rise to diurnal descendants (Trogonidae and Apodiformes), both
of which retained the extreme aerial specialisations of their ancestors.
    It might also result in a re-examination of the Archaeotrogonidae, which
were transferred from Trogoniformes to Caprimulgiformes a little while ago.
Maybe the two interpretations of their relationships were both right, after
all :)

    Cheers,

        Christopher Taylor

Mayr, G. 2003. On the phylogenetic relationships of trogons. Journal of
Avian Biology 34: 81-88.
Mayr, G., & J. Clarke. 2003. The deep divergences of neornithine birds: A
phylogenetic analysis of morphological characters. Cladistics 19: 527-553.

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))
> 
> _________________________________________________________________
> Speel games met je online vrienden via MSN Messenger
> http://messenger.msn.nl/
> 
>