Re: Sauropod nostrils (was RE: joke........)

["Matthew Bonnan" <mbonnan@hotmail.com>]

Good points so far on sauropod nostrils.  There are some reptiles (of 
course, my references are not at hand since I am writing from home, so give 
me some time here!) with retracted narials and nostrils for no particular 
"reason."

Forgive me for not having refs right now, but I want to make it clear that 
this is not my idea.  It might stem from McNamara's work on heterochrony in 
dinosaurs.  Heterochrony (for those on this list who are not familiar with 
the term) literally means different time.  This different time is in 
relation to embryonic and ontogenetic (growth) stages.  Some animals retain 
juvenile characters into adulthood by maturing at an earlier ontogenetic 
stage, while others extend their growth into "super" adult stages.

Perhaps sauropod nasal position has to do with neotony (retaining juvenile 
characters into adulthood).  Embryonic prosauropods like Mussasaurus have 
nostrils placed higher on the head and closer to the orbit than adult 
prosauropods which have sniffers in the front.  Maybe sauropods retained a 
juvenile characteristic in the skull through neotony?  Perhaps also their 
cartilaginous joints and apparently rapid growth stem from the same thing?  
Any thoughts?

Just my two sauropod cents.

On another note, someone asked me about a reference for the reply to the 
Parrish/Stevens neck paper.  It is a one page article by Rieppel and Brochu 
in Field Notes from the Field Museum, but alas the ref eludes me now.  
However, some of the info in that article on Brachiosaurus neck posture 
appears to be derived from the following paper on vertebral compression:

Christian, A. and W.-D. Heinrich. 1998. The neck posture of _Brachiosaurus 
brancai_. Mitt. Mus. Nat.kd. Berl. Geowiss. Reihe 1: 73-80.

Many happy nostrils and vertebrae to you,
Matt

P.S. Limbs and feet are far more interesting! =)

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