Re: Hummingbird -- the littlest dinosaur!

[David Marjanovic <david.marjanovic@gmx.at>]

----- Original Message -----
From: "Paul Penkalski" <turtlecroc@yahoo.com>
Sent: Friday, April 08, 2005 3:56 AM

> By that logic, if dinosaurs are reptiles, as you
> assert in your previous msg, and hummingbirds
> are dinosaurs, then hummingbirds must be reptiles.
> Huh.

Depends on the definition. If you stick to tradition and use "Reptilia" for 
the grade of amniotes that are neither mammals nor {birds, or dinosaurs in 
general}, then hummingbirds still aren't reptiles. If you take the 
phylogenetic definition, the "horizontal" meaning gets toppled into a 
"vertical" one. All "mammal-like reptiles", even *Dimetrodon* and 
*Varanops*, stop being reptiles (once I've even seen the term "reptile-like 
synapsids"!), while all descendants of the most recent common ancestor of 
turtles, crocs and lizards, such as for example birds, become reptiles.

Personally I don't see why Reptilia should get a phylogenetic definition at 
all. We already have the venerable old name Sauropsida for almost exactly 
the same clade.