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Re: Hummingbird -- the littlest dinosaur!



----- 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.