Re: Giant flightless birds

["Jaime Headden" <jaemei@hotmail.com>]

<<<Ratites, of course, still exist (ostrich, emu, cassowaries, rheas, 
kiwis and, depending on whom you read, the tinamous, which also fly), 
as do the seriemas which are related to the phorusracoids. The nearest 
relatives of Diatryma are, I believe, uncertain, though relationship to 
cranes has been postulated.>>>

<<Rails or cranes, plus ducks (and therefore geese).>>

<Are you implying that rails/cranes and ducks constitute a clade? 
Something along those lines has never been really considered and is very 
unlieky.>

Besides basically being primitive? No. I meant that each was a possible 
canidate for "closest relative"; I did say 'or' but I shouldn't've said 
'plus'. My mistake.

<<The purpose of my query is to gather data on groups of extinct 
flightless birds to trace phylogeny to living forms and to the 
dinosaurs. (Flightlessness being an ancestral trait and therefore a 
semi-good marker for phylogenetic research, in my opinion. Of course, 
I've said that before.) I'm trying to find out the adaptations of the 
rest of the body in addition to/or because of the loss of flight. 
Especially the pelvis.>>

<Well, let's talk about a flightless bird's pelvis. If alvarezosaurids 
are birds, then they show a unique amount of variation in the structure 
of the pelvis compared to other birds. Patagopteryx is 
convergent on some ratites in the morphology of the pelvis (pubis and 
ischium are of equal length and are nearly parallel, with a small 
foot-like process on the dital end).>

First I've heard that on *Patagopteryx*.

<One of the strangest trends in flightless birds is the convergent 
morphology of the pelvis. Some flightless ratites, anseriformes, 
gruiformes, galliforms, podicipediformes, gaviiformes, and even 
hesperornithiformes have a arrangements of the pelvis where the pubis 
and ischium are nearly horizontal and extend to the distal end of the 
pygostyle.>

Ostriches have a pubic symphysis, if I'm not mistaken, while nearly all 
other avian pelvises do not (e.g., passerines, strigiforms, penguins, 
falconiforms). This may be a atavism, retroeval character, or something 
else entirely, if true.

<The pelvis in phorusrhacids, however, is not in this arrangement, and 
it resembles more of that of a flighted, volant bird. The arrangement is 
conservative in all lineages of flightless birds (and I have only 
scratched the surface on the diversity of them). It should be noted, 
with *perhaps* the exception of Spenisciformes (penguins) and the 
possiblilty of aquatic gaviiform ancestors, that most flightless birds 
evolved in parallel of each other and they evolved the structure of 
their pelvis convergently.>

This brings me to something. I'm trying to get a hold of more info on 
*Phorusrhacos*, especially something more than a restoration---skull, 
arm, etc. Somewhere on the net, and article, a book....

Would be very helpful, and I would be very thankful.

<MattTroutman>

Jaime A. Headden

PS: by the way, if you know, how many avian taxa have a notarium? 

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