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Re: choana [was SOME SVP TIDBITS]
At 03:33 PM 10/15/98 -0400, Norm King wrote:
>One is that the choana is the passageway by which animals get air into
>the mouth/throat while keeping the mouth closed. It appeared first among
>sarcopterygians, and sarcopertygians plus tetrapods are "choanates". It
>includes everything from the external nostrils to the internal nostrils
>(nares, if we're just talking about holes through the bone), or from the
>external nostrils to the back of a secondary palate, for animals that
>have one. It is the whole passageway; there is no special name for the
>passage between the primary and secondary palate.
>I suspect that the first definition was the original one. Otherwise, why
>have a separate word? Then, through use (misuse?), it came to also mean
>internal nostril. I'm speculating.
>Anyway, now I feel better. Thank you, Norm.
>You're welcome, Norm.
Yes, thank you, Norm.
It would indeed be interesting to find out the history of the term: I
suspect you are correct.
In any case, back to the original observations (at least, I THINK this is
where we started out...):
The internal nares (internal nostrils) of _Velociraptor_ and of spinosaurids
were shown at SVP (and the recent spinosaur paper by Taquet & Russell) to be
much further back in the snout than previously thought.
Thomas R. Holtz, Jr.
Vertebrate Paleontologist Webpage: http://www.geol.umd.edu
Dept. of Geology Email:firstname.lastname@example.org
University of Maryland Phone:301-405-4084
College Park, MD 20742 Fax: 301-314-9661