Re: Dino Birds (was Re: Dinosaur = extinct animal)

["Jaime A. Headden" <qilongia@yahoo.com>]

Chris Brochu wrote:

<<The overall point is that paraphyletic assemblages,
above the species level, are subjective, have no
biological reality, and are not recognized in modern
systematics.>>

<Paraphyletic taxa certainly have "biological
reality," whatever that is.>

[snip]

<Among dinosaurs, the genus Hypacrosaurus is probably
paraphyletic, since it doesn't include the species in
the probable descendant genera Corythosaurus and
Lambeosaurus (see Currie & Horner on Hypacrosaurus
stebingeri), and the genus Chasmosaurus, since it
doesn't include the species in the probable descendant
genus Pentaceratops (see Lehman on Chasmosaurus 
mariscalensis).>

  The problem here is the line between genus and
genus, or species and species. How many characters
does it take to differentiate between *Velociraptor*
and *Deinonychus*, or synonymize them? *Chasmo.
mariscalensis* is the name applie for one side of the
split that also produces *Penta.*, and same for the
lambeosaurs, whereas *Corytho.* was part of an earlier
split with whatever split into the groups we now
identify as *Hypacro.* and *Lambeo.* This makes
neither of these taxa paraphyletic. Instead, an animal
as differentiated into several recognizable groups.
The naturality of the names themselves is at question,
not their monophyly; that is, one should perceive that
_all_ these names are paraphyletic, including
Hominidae, Australopithecinae, Lambeosauridae,
Tetrapoda, Amniota, Canidae, Sarcopterygii,
Archaeobacteria, etc., because everything stemmed from
something else. Taxonomy applies names to better
differentiate this all to some reasonable order, as
far as I see it.

  For my own interests, the problem of the *E.
elegans* feet represents the same conundrum, where the
foot possesses features of both *Elmisaurus* and
*Chirostenotes*, a likely transistory entity, and from
the discussion earlier last month, it became clear to
me that this animal does not appear likely to belong
to either genus (i.e., is paraphyletic). Something
relevant.

===
Jaime A. Headden

"May I lure us, ere the mote ends us?"

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