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VARIOUS NOTES ON BIRD PHYLOGENY




Lot of stuff on birds, the often-forgetted living dinosaurs, on the list 
lately: ducks, chickens, stilts and flamingos; K parrots; and basal 
birds.  I'll condense it all into one rather large message. 

FLAMINGOS AND STILTS, DUCKS AND CHICKENS

<<Olson and Feduccia (1980), in their big _Smithsonian Contributions to 
Zoology_ paper on flamingo affinities, asserted that _Cladorhynchus_, 
the Australian banded stilt, was a close relative of flamingos. As some 
of us have pointed out on this list before (see  
http://www.cmnh.org/fun/dinosaur-archive/1996Jan/0211.html), the two 
share some characters: the structure of their eggshells, the habit of  
breeding in massive colonies in shallow alkaline lakes, and a few  vague 
morphological things like a certain leg muscle (the iliotibialis medius 
if memory serves). The proposition, thus, is that there is a 
_Cladorhynchus_ + Phoenicopteriformes clade.>>

Yep, its the M. iliotibialis medialis.  The evidence, too vast to list 
completely in detail here, includes features of nesting behavior, life 
history, natal down, appendicular myology (many peculiarities here), 
pterylosis, oology, parasitology, biochemistry, cranial osteology, 
postcranial osteology (especially hindlimb elements), and 
paleontological evidence from _Juncitarsus_.  In my opinion, its very 
strong.  

<<Now, this should not be confused with Feduccia's earlier speculations 
that flamingos evolved from stilt-like ancestors and that 
presbyornithids diverged from this lineage and evolved into ducks. If 
this all sounds very vague and extremely confusing, that's because it 
is: flamingos, ducks, presbyornithids and waders were all linked 
together into a sort of messy nexus that would, supposedly, be 
unresolvable by cladistic methods.>>

Livezey's recent paper on anseriform evolution deals with this issue 
quite nicely.  He casts considerable doubt on the reliance on 
"evolutionary mosaics" by workers such as Feduccia and Olson.  Livezey's 
paper is quite compelling and may eventually turn me around to advocate 
the "duck-chicken" relationship.  The ecomorphological twist was 
especially interesting. 

<<In allying anseriforms with charadriiforms and flamingos (something 
that may (Ericson 1997) or may not (Livezy 1997) be correct), Olson 
and Feduccia have of course removed any link between anseriforms and 
galliforms.>>

Ericson (1997), following some previous works, based on cladistic 
analysis, argued for an association between certain ciconiiforms (which 
were polyphyletic according to his analysis), including flamingos, and 
anseriforms.  Of the interesting notes in his listing of characters, he 
argued that the retroarticular processes of phoenicopterids are more 
similiar to anseriform retroarticular processes than galliform 
retroarticular processes.  

Livezey (1997) and Ericson (1997) differed on points of chracter 
polarity in anseriforms, particulary in anhimids (screamers) and 
presbyornithids (_Presbyornis_ and allies).  Livezey argued that the 
vaguely charadriiform (that is, to the less bird oriented on the list, 
shorebirds) "four-notched" sternum in _Presbyornis_ is in fact not 
homologous to the charadriiform sternum.  Vestigal lamellae of anhimids 
are primitive to anseriforms as well as the fowl-like bill and 
rudimentary webbing of the feet (also shared with _Anseranas_, another 
basal anseriform).  Ericson (1997) argued in a way similiar to Olson and 
Feduccia (1980) in several points; duck-like bill is primitive for 
Anseriformes, whereas the anhimid condition is secondary, etc.

<<I cannot help but feel that Olson and Feduccia were trying their very 
hardest to keep screamers as far as possible from the galliforms, a 
group they have obvious similarities to. It may be that they tried to 
achieve this by making out that screamers were very specialized 
anseriforms.>> 

Amen!

<<The problem is that this is _not_ seen in phasianids - the galliforms 
most readily available as study specimens for workers the world over 
- and those who have argued that anseriforms and galliforms are 
radically different with regard to this feature have relied heavily 
on the morphology of _Gallus_ (Interestingly, Witmer (1991) noted 
that reliance on _Gallus_ in studies of cranial pneumaticity in birds 
were also misleading as it is actually a very atypical bird!). 
Cracids and megapodes, I think univerally agreed upon as the most 
primitive of extant galliforms, do have the compressed blade-like 
retroarticular process, something Ericson (1997) pointed out in his 
recent paper (though if anything is clear from this discussion, it is 
that I will have to go and look at some specimens to make up my own 
mind).>>

Very interesting that in both of the papers both Livezey and Ericson 
used the vast diversity of galliforms to their advantage.  

<<Again, Cracraft has been quite vocal in disputing Olson and 
Feduccia's claims that _Cladorhynchus_ is the sister-group to 
flamingos. He argued against it in both his big _Auk_ paper from 
1981, and in his contribution to _Phylogeny of the Tetrapods, Vol. 1_ 
(1989?). His objections concern logical aspects of cladism, and not 
necessarily the data: while Olson and Feduccia seem to indicate that 
they visualise the whole flamingo-stilt thing as...>>

Cracraft's arguments are extremely cladist in form; e.g., the 
similiairities of _Cladorhynchus_ and flamingos may not be valid because 
other recurvirostrids do not have some of these features.  Cracraft 
argued that the similiarities between _Cladorhynchus_ and flamingos will 
be interpreted as convergences because flamingos show some vaguely 
ciconiiform-like characters.  He also argued that _Juncitarsus_ was not 
flamingo-like.  

<<.. they state elsewhere in their paper that flamingos should not be 
included **within** the recurvirostrids, but 'listed after them'. 
This implies, I think, that they are then saying that recurvirostrids 
and flamingos are sister-taxa.. which would then be contrary to their 
argument that _Cladorhynchus_ represents the sister-taxon to 
flamingos! The real problem here, of course, is hard-line cladistics 
vs. the intuitive paradigm; Cracraft is a strict adherant to the 
former, Olson and Feduccia to the latter.>>

No one has really made a vigorous cladistic analysis made to determine 
the relationships between recurvirostrids, charadriiforms, ciconiiforms, 
flamingos and anything else.  Livezey also argues against the intuitive 
methodology quite effectively.

<<Cracraft and others state plainly that the _Cladorhynchus_-flamingo 
thing is a convergence that has come about through similar nesting 
habits. Cyril Walker argued with me recently that that one muscle 
character - the iliotibialis medius or whatever it's called - common 
to both groups is hardly concrete proof of their affinity. I await to 
be convinced by a cladistic study that firmly allies flamingos with a 
group of birds other than charadriiforms, and agree with Olson and 
Feduccia that banded stilts and flamingos are indeed similar. Whether 
or not these similarities are indicative of convergence or affinity.. 
don't know.>>

Walker is understating the similiarities.  The similiarities are very 
vast and I think that there are more to the thing than a single muscle 
(though it is compelling).  

CRETACEOUS PARROTS

Having just read Stidham's very interesting paper, I think that there is 
some evidence to suggest that the dentary (which is very bird-like and 
parrot-like) is from a psittaciform.  I have doubts that it is a loriid; 
the rounded rostral end of the symphysis, the deeply concave symphysis, 
and the concave tomial crest ARE found in loriids (which possess many 
specializations that make them very cool birds), but, as Stidham points 
out, are also found in macaws and some other psittacids.  The K-shaped 
neurovascular canal pattern and deeply concave symphysis are pretty 
telling.  But, as I know that some people think, it IS possible that 
these features could have evolved in parallel.  It could be that these 
features are primitive for Psittaciformes and their MRCA (whatever that 
may be; I vote possible coliiform relative) and it is a parrot ancestor 
in the K.  I think that it is a very possible real parrot from the 
Lance, but I remain skeptical.

CLIMBING CASSOWARYS 

I said recently on the list that cassowarys can climb.  Though I meant 
to say seriemas, I believe that I have heard that cassowarys do try to 
traverse upwards on trees towards their hunters.  I could be wrong, 
though.  

_ARCHAEOPTERYX_ AND ITS RELATIVES  

Speaking strictly, all birds are closely related to _Archaeopteryx_, but 
there are various groups that take a position more basal on the avian 
tree (to say "more basal" is not the same as saying "more primitive"; 
every lifeform on earth is "advanced" and "primitive" in tis own way).  
Palaeognathous birds are probably the closest to the MRCA of Neornithes.  
Which group of palaeognaths is the closest (that would be the most basal 
member of the group) the MRCA is another question.  Tinamous have been 
considered the most basal traditionally, mainly because of their volant 
habits.  Increasingly, however, there is some evidence that suggests a 
relationship between tinamous and the various neognaths.  This does not 
really change the position of the tinamous among the palaeognaths, but 
it does provide some complexities.  Lithornithids, which are most likely 
the ancestors of ratites, may be another basal palaeognath group.  Of 
course, there is always the vexing question of whether or not 
palaeognaths are monophyletic, paraphyletic, or polyphyletic.  Also 
confusing the situation is the fact that some traditional neognaths, may 
occupy a more basal position than previously anticipated in Neornithes.  
Jeffery Woodbury, basing his conclusions on the spinal cord anatomy of 
Recent birds, argued that palaeognaths, "core gruiforms" (cranes, rails, 
trumpeters, sungrebes, mesites, and buttonquails), Columbiformes, 
Cuculiformes (though not the musophagids nor the hoatzin), Pici and one 
family from Galbulae, and Passeriformes, are a clade of basal 
neornithines, the 'Leioceratae'.  All other birds fill out the 
'Schizoceratae'.  Needless to say, this analysis is highly 
controversial, though it does fill out some prophecies (mesites and 
buttonquails are more basal than previously realized).  I don't buy 
polyphyly of Galbulae, but the evidence paints a different picture in 
this case.  I applaud Woodbury for his courage in publishing this, but I 
don't think he should have went by the Wetmore classification.

Whew.  Anyway, everybody I own an email to I'll get back to you later.  
Maybe as late as next year.  Sorry.

Matt Troutman 
m_troutman@hotmail.com


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