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Finally recieved a copy of Olson 1983, _Evidence for a Polyphyletic
Origin of the Piciformes. Boy, what a great paper.
To those of you who do not know, Piciformes is the bird order that
contains woodpeckers, toucans, honeyguides, and traditionally puffbirds
and jamacers (Galbulae). Two years before Olson's paper was published
there were two cladistic analyses that supported the classical,
monophyletic view of Piciformes. The features given were obligate
zygodactly ("the condition in which the fourth toe is permenently
reversed and has an enlarged accessory articulating process (the
"sehnenhalter") Olson 1983; 126), three-headed M.flexor hallucis longus,
and Type VI flexor tendons. These are the only characters holding the
classical Piciformes together. As Olson shows, obligate zygodactly
occurs in cuckoos and parrots, the M.flexor hallucis longus is not
three-headed in Galbulae, and the Type VI flexor tendons is probably
convergent (a similiar case of convergence as Olson points out is the
similiar branch of the M.extensor digitorum longus extending to the
hallux in parrots and mousebirds).
Olson shows that the suborder Galbulae actually shows more characters in
common with the rollers, Coracii, of the order Coraciiformes. They show
a similiarity to coraciids in bill shape, truncate palatines, straight
and narrow pterygiods, heavily ossified nasal septum, shape and position
of the temporal fossae, inflated ectethemoid plate, and greatly
exaggerated and ventrally projecting postorbital process. The
postorbital process takes special emphasis in Olson's mind. The process
is "enlarged and extends straight ventrally as far as the jugal bar"
(Olson 1983; 130); there is a similiar short and strong postorbital
ligament that attaches to the medial surface of the mandible just
anterior to the articulation; the M.adductor mandibulae complex is
narrowed, and passes through a tiny foramen in the postorbital process.
The coracoids, humerus, down, oil gland and carpometacarpus are all
Olson points out that the only features uniting the classical Piciformes
are only deep flexor tendors. Galbulae and Coraciiformes all show more
similiarities to each other than Galbulae shows to Piciformes.
Olson goes on to note the similiarities between Pici and Passeriformes:
similiar coracoids that are slender and elongate, with the sternal end
narrow, sternocoracoidal process reduced and procoracoid process reduced
or absent, carpotmetacarpus, down feathers, and several myological
Great paper. It is also a good introduction to birds for novices. I
suggest it to all.
Olson, S.L. 1983. Evidence for a Polyphyletic Origin of the Piciformes.
Auk 100: 126-133.
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