Re: _Parasaurolophus'_ crest and how much we can't deduce from it.

[Robert.J.Meyerson@uwrf.edu (Rob Meyerson)]

Peter Buchholz writes;

>I really don't see what difference making the pipes the same size and shape
>of _P._'s crest will make.
>
>An analouge to this is the different types and styles of brass instruments;
>take a trumpet and flueggel-horn for example.

Right direction, wrong instrument.  Consider the trombone: the sound that is=
 produced is determined by the length of the tube (altered by moving the=
 slide back and forth).  So by constructing a "trombone" to Para's standards=
 will give an idea of the basic sound made by the animal(similar to the=
 human "Ah," heard when P. Domingo is warming up).

>In a trumpet the mouth-piece has a
>very shallow cup making the tone very bright, and accordingly you >can play
>trumpets very loudly without trying very hard.  In contrast, a >flueggel-ho=
rn
>(for those of you who don't know, a flueggel-horn is a brass >instrument
>similar in size and shape to a trumpet; it's slightly larger and the >pipes
>look funny) has a mouth-piece that has a very deep cup making the >tone mor=
e
>mellow and non-dirrectional, even though the instrument itself is >very
>similar in size and shape.

Actually, your trumpet/flueggel horn points out that subtle changes in the=
 air flow can produce a very different sound (consider ol' Domingo's vocal=
 range again).  By studing accoustical dynamics, it has been shown that when=
 the air flow in two air sources is identical, the sound from those sources=
 are identical (no reference; check your local music department).  Likewise,=
 by analyzing the airflow of a hadrosaur, and making a replica, one can get=
 a good idea of how tha animal actually sounded.

>What I'm getting at is, we can't really deduce much of how _Parasaurolophus=
_,
>or any other Hypacrosaurine, sounded like unless we know the shape of the
>openning into the larynx, i.e. whether it was shallow or deep.  Since that =
is
>almost entirely soft-anatomy that probably wouldn't fossilize, we can't
>really tell how they sounded much more than the basic range of the animal.

Knowing the soft part morphology would tell us the range of sounds possible=
 by the animal, something we could never get from the skull alone.  However,=
 the basic sounds can be determined by an accoustical analysis of the head r=
egion.

>Just thought of something.  On the _H. casuarius_ 'mummies,' have the throa=
ts
>been preserved, especially the voice boxes?  If we could see the openning t=
o
>the voice-box on these, then we could probably make generalizations about t=
he
>whole family, if their calls were bright and loud or mellow and
>non-dirrectional.

It would be an intriguing notion (I don't know if its true or not).  Perhaps=
 adding a typical hadrosaur voice box to Weishample's model would give us an=
 insight into the dynamics of Para's song.

>Maybe they could even change the depth of the opening to make some calls,
>like mating calls maybe, more bright and loud (and obnoxious); and make oth=
er
>calls like warnings more mellow and non-dirrectional.  Who knows?

Since this range of vocalization works well in songbirds, then your=
 hypothesis is probably correct (although it may describe the crested=
 hadrosaurs better than the non-crested ones.

Rob