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Re: Archaeopteryx



----- Original Message ----- 
From: <Dinogeorge@aol.com>
To: <dinosaur@usc.edu>
Sent: Monday, June 16, 2003 1:15 PM
Subject: Re: Archaeopteryx


> In a message dated 6/15/03 8:08:27 PM Pacific Daylight Time,
> cmchenry@westserv.net.au writes:
>
> << This might make a few people choke on their cornflakes. >>
>
> You ought to see what they do when I suggest every so often that Aves be
> defined to include all of Dinosauria.
>

Yeah, well let's see what they do with this one.....


----- Original Message ----- 
From: "T. Michael Keesey" <mightyodinn@yahoo.com>
To: "Mailing List - Dinosaur" <dinosaur@usc.edu>
Sent: Monday, June 16, 2003 12:04 PM
Subject: Re: Archaeopteryx


> If you have a better definition for _Aves_, let us know.
> (Incidentally, some researchers do use a different definition, a crown
group
> equivalent to _Neornithes_.)
>

The term Aves was originally coined by Linnaeus to provide a collective term
for living feathered beasties.  If I remember correctly, the term was then
used by Chiappe as an equivalent name for Gauthier's (1986) and Padian's
(1997) Avialae.

Sensu Chaippe, Aves is a long way from the original definition intended by
Linnaeus.  It seems to me that the only reason why Chiappe was able to
reappropriate the word is that taxa above families are not subject to the
rules of the Code.  Otherwise, the modern definition of Aves would be a
cladistic rephrasing of Linnaeus' - i.e.equals Neornithes.  As far as I
understand, if the Code applied to taxa above the family, then Aves would be
a senior synomym of Neornithes.

I often feel that the lack of application of the Code to higher taxa is a
shame.  There are some wonderful names out there, which have fallen by the
wayside because of this.  An example, from the animals with which I am most
familiar, is the Enaliosauria.  This was oringinally used by Conybeare (I
think the earliest use in print was 1824, but would welcome any further
information on this) as a collective term for Ichthyosaurus and
Plesiosaurus.  Later, when the old 'Romer' scheme of classifying reptiles by
skull temporal fenestration was popular, they were both included as
Euryapsids (one upper temporal opening in each side of the skull), and the
term Enaliosauria fell out of use.  Then, with the advent of cladistic
analysis, plesiosaurs were assigned to the Diapsida.  Eventually, about 8
years ago, Mike Caldwell found ichthyosaurs to lie within the diapsids, and
(just to prove that there's nothing new under the sun) he also found them to
be the sister group of Sauropterygians.  Unfortunately, he resurrected the
term Euryapsida to include Ichthyosauria + Sauropterygia, instead of using
the opportunity to use Conybeare's original (and etymologically superior)
term.  This was despite the fact that this new use of Euryapsida is very
different, in definition and conceptual intent, from that meant by Romer and
others, and that Conybeare's terms was specifically intended to mean
Ichthyosauria and Sauropterygia.

I do admit to suffering a case of nomenclatural heritage-itis, but there you
go. The situation isn't quite the same as that for Aves, because in this
case Enaliosauria has not been appropriated for use in a context quite
different to the one originally intended by Conybeare.  But I still think
that, for higher taxa that date to Linnaean times, some sensitivity to the
heritage of these names would not go astray when applying cladistic
definitions to them.  And yes, I am aware that Huxley was the first to apply
the word 'bird' to Archaeopteryx, but I think the context of that statement
was very different to the taxonomic aruguments under discussion here (and
did he use the term Aves?).  Any way, for reasons largely to do with
remaining consistent with the original use of the word, I would prefer to
see the term Aves being made equivalent to Neornithines, and finding another
word to denote Archaeopteryx + Neornithines (what was wrong with Gauthier's
Avialae?).

My 2c worth.

Cheers
Colin