Non-theropod furculae

["Jerry D. Harris" <LOKICORP@compuserve.com>]

George wrote:
>Since a well-developed furcula is known for _Longisquama_, we can expect
to 
>find it WAY WAY back in the early days of Theropoda!

...and then Ray wrote:
But since _Longisquama_ isn't a dinosaur but an archosaur ("thecodont") of
uncertain affinities (to my knowledge), maybe the furcula may have
developed independently within the archosaur group. Let's look for an early
theropod, say an _Eoraptor_ relative, for a furcula.

        Given that the lone, incomplete specimen of _Longisquama_ is an
impression, lacking any actual bone, I would be 
_very_ wary of interpreting any aspects of its true osteology, particularly
where tiny nuances present in the real bone might 
be lacking in the impression.  For example, I am currently studying a
small, articulated pectoral girdle from the Chinle 
which possesses articulated scapulocoracoids, clavicles, and sternal
plates.  The clavicles form a broad U- (or parabola-) 
shaped structure, and the suture between them is subtle but definitely
present.  Were I to impress the element into a fine-
grained mud, I doubt the suture would show up, and the impression would
resemble a furcula.

        The specimen is very likely _not_ a theropod; it bears, instead,
similarities to megalancosaurids, drepanosaurids, 
and the "deep-tailed swimmer" of the Newark Supergroup, particularly in
scapular morphology.  Oh, and the scapula is also 
a little similar to _Longisquama_...  Hope to have the thing written up and
submitted soon!
        


                _,_
           ____/_\,)                    ..  _   
--____-===(  _\/                         \\/ \-----_---__
           /\  '                        ^__/>/\____\--------
__________/__\_ ____________________________.//__.//_________

                     Jerry D. Harris
                 Fossil Preparation Lab
          New Mexico Museum of Natural History
                   1801 Mountain Rd NW
               Albuquerque  NM  87104-1375
                 Phone:  (505) 899-2809
                  Fax: ; (505) 841-2866
               102354.2222@compuserve.com
=========================== RichMail Header ==============
This section contains RTF format of the main message generated by
RichMail software, available at "WWW.RichMail.net". It can also be viewed
by copying, saving as "*.rtf" in NotePad and opening in any word processor.
=========================== RichMail Begin ===============
{\rtf1\ansi\ansicpg1252\deff0\deftab720{\fonttbl{\f0\fswiss MS Sans
Serif;}{\f1\froman\fcharset2 Symbol;}{\f2\fswiss\fcharset1
Arial;}{\f3\fswiss\fprq2 System;}{\f4\fswiss\fcharset1 Arial;}}
{\colortbl\red0\green0\blue0;}
\deflang1033\pard\plain\f4\fs20 George wrote:
\par >Since a well-developed furcula is known for _Longisquama_, we can
expect to 
\par >find it WAY WAY back in the early days of Theropoda!
\par 
\par ...and then Ray wrote:
\par But since _Longisquama_ isn't a dinosaur but an archosaur
("thecodont") of
\par uncertain affinities (to my knowledge), maybe the furcula may have
\par developed independently within the archosaur group. Let's look for an
early
\par theropod, say an _Eoraptor_ relative, for a furcula.\plain\f2\fs20 
\par 
\par \tab Given that the lone, incomplete specimen of _Longisquama_ is an
impression, lacking any actual bone, I would be _very_ wary of interpreting
any aspects of its true osteology, particularly where tiny nuances present
in the real bone might be lacking in the impression.  For example, I am
currently studying a small, articulated pectoral girdle from the Chinle
which possesses articulated scapulocoracoids, clavicles, and sternal
plates.  The clavicles form a broad U- (or parabola-) shaped structure, and
the suture between them is subtle but definitely present.  Were I to
impress the element into a fine-grained mud, I doubt the suture would show
up, and the impression would resemble a furcula.
\par 
\par \tab The specimen is very likely _not_ a theropod; it bears, instead,
similarities to megalancosaurids, drepanosaurids, and the "deep-tailed
swimmer" of the Newark Supergroup, particularly in scapular morphology. 
Oh, and the scapula is also a little similar to _Longisquama_...  Hope to
have the thing written up and submitted soon!
\par \tab 
\par 
\par 
\par \~\~\~\~\~\~\~\~\~\~\~\~\~\~\~ _,_
\par \~\~\~\~\~\~\~\~\~\~ ____/_\\,)\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~
..\~ _\~\~ 
\par --____-===(\~ _\\/\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~
\\\\/ \\-----_---__
\par \~\~\~\~\~\~\~\~\~\~ /\\\~
'\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~ ^__/>/\\____\\--------
\par __________/__\\_ ____________________________.//__.//_________
\par 
\par \~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~ Jerry D. Harris
\par \~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~ Fossil Preparation Lab
\par \~\~\~\~\~\~\~\~\~ New Mexico Museum of Natural History
\par \~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~ 1801 Mountain Rd NW
\par \~\~\~\~\~\~\~\~\~\~\~\~\~\~ Albuquerque\~ NM\~ 87104-1375
\par \~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~ Phone:\~ (505) 899-2809
\par \~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~ Fax:\~ (505) 841-2866
\par \~\~\~\~\~\~\~\~\~\~\~\~\~\~ 102354.2222@compuserve.com
\par }
=========================== RichMail End =================