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Re: Plesiosaurs Necks



One has to be careful applying simple aerodynamic
assumptions to animals:
The swift is one of the most streamlined birds and there are
many claims of high-speed flight that have been made.
But most evidence indicates that it is one of the slowest
birds and it's high-effeciency structure is tied to allowing
it to spend something like 12-16 hours a day feeding on the
wing.

Large flipper size would tend to favour relatively slow high
effeciency movements (displacing a large amount of water at
a lower speed).

I also find it interesting to look at the cross-section
build up toward the front, which, along with the relatively
large forward limbs suggests interesting caracteristics and
manuvering possibilities.

The long neck of an elasmosaur seem to suggest significant
limits to the rate at which it could be turned with the
animal and raises interesting questions about life
behaviours. Any thoughts?

Thank you Mr. Habib for the references and as always thank
you to the DML!
-Jonas Weselake-George
Ottawa Paleontological Society

----- Original Message -----
From: Dinosaur World <dinoworld@msn.com>
To: <Ken.Carpenter@dmns.org>; <dinosaur@usc.edu>
Sent: Sunday, January 15, 2006 6:50 PM
Subject: RE: Plesiosaurs Necks


Thanks Dr. C.

I guess high rate of speed was a poor choice of words.
Perhaps I should have
said ANY rate speed instead.

The idea that they were fast is based on the basic
aerodynamic design of the
flippers, as well as their size and positioning on the body.
The dual
flippers appear to me to be capable of moving the body
swiftly through the
water and allowing it to change directions very abruptly.

This suggests to me that they were active, fast moving
animals. What I don't
understand is if the necks were somewhat ridged, wouldn't
this prevent them
from "snaking" their necks through the water in an attempt
to catch prey?
Were fast moving fish not a big part of their diet?





From: <Ken.Carpenter@dmns.org>
To: <dinoworld@msn.com>,<dinosaur@usc.edu>
Subject: RE: Plesiosaurs Necks
Date: Sun, 15 Jan 2006 16:25:10 -0700

Well, what is a high rate of speed, and why do you assume
they swam
fast? Considering how much interspinal ligament was probably
present for
most of the neck (based on scars), it was (unlike the debate
on sauropod
necks) a fairly rigid neck.

Ken


Kenneth Carpenter, Ph.D.
Curator of Lower Vertebrate Paleontology/
Chief Preparator
Department of Earth Sciences
Denver Museum of Nature & Science
2001 Colorado Blvd.
Denver, CO 80205

Phone: 303-370-6392
Fax: 303-331-6492
************************************************************
for PDFs of some of my publications, as well as information
of the Cedar
Mountain Project:
https://scientists.dmns.org/sites/kencarpenter/default.aspx

-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]
On Behalf
Of Dinosaur World
Sent: Sunday, January 15, 2006 4:11 PM
To: dinosaur@usc.edu
Subject: Plesiosaurs Necks

Has there been studies to try and determine how a
Plesiosaur, especially
Elasmosaurus, would have been capable of holding their necks
straight
while swimming at a high rate of speed?

What would have prevented the neck from simply folding
backwards due to
the force of the oncoming water?

George