RE: Trogons and Grebes

[Tim Williams <twilliams_alpha@hotmail.com>]

Jaime Headden wrote:

>   Mayr. G. 2005. New trogons from the early Tertiary of Germany. _Ibis_ 
> 147(3):512-518.
> *Primotrogon? pumilio* and all other sufficiently well-preserved early 
> Tertiary trogons appear to be stem group representatives of the 
> Trogoniformes,

A strict phylogenetic taxonomist would probably call this clade 
"Pantrogoniformes".

>   Sangster, G. 2005. A name for the flamingo--grebe clade. _Ibis_ 
> 147(3):612-615.

The new name in question is "Mirandornithes", meaning "wonderful birds"...

"The name Mirandornithes refers to the least inclusive clade comprising 
_Phoenicopterus ruber_ Linnaeus, 1758 and _Podiceps cristatus_ (Linnaeus, 
1758).  _Phoenicopterus ruber_ and _Podiceps cristatus_ are selected as 
reference taxa because these are the type species of _Phoenicopterus_ and 
_Podiceps_, respectively, on which the names Phoenicopteridae and 
Podicipedidae, respectively, are based.  A node- rather than a stem-based 
definition of Mirandornithes is selected because its sister-taxon is 
unresolved (see below), as recommended by Sereno (1999)."

A few things concerned me about this paper, such as the rejection of a 
Gaviidae-Podicipedidae clade, as found by Mayr & Clarke (2003) .  Says 
Sangster: "Most of the shared derived similarities of these birds are found 
in the pelvis and hind limb, and these similarities are probably due to 
convergence resulting from the similar foot-propelled diving habits of 
divers and grebes..." This may be true (and I suspect it is); but can we 
reject the alternative hypothesis that foot-propelled diving is primitive 
for both divers and grebes?  If _Neogaeornis_ and _Polarornis_ (both 
foot-propelled diving birds fro the LK) are indeed divers (loons), then the 
Gaviidae is a very ancient group.

Cheers

Tim