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Re: surface/volume ratio and water loss in smallest amniotes
This is a research project that is begging to be done.
Many eons ago, I measured the water loss from a leopard frog, using a
high-precision electronic scale. He was very cooperative, which allowed a
precision down to 0.0001 grams.
The largest abount of error was introduced by his breathing pattern....which
modulated his weight around +/-0.1 grams per breath cycle.
With pteros, you won't have to worry about your subject breathing, but your
biggest unknown will be the gas-exchange characteristics of ptero skin. You
could model a variety of different skin characteristics to get a range of
All-in-all, a very do-able project.
---------- Original Message ----------
From: David Peters <firstname.lastname@example.org>
To: Jocelyn Falconnet <email@example.com>
Cc: dinosaur mailing list <firstname.lastname@example.org>
Subject: Re: surface/volume ratio and water loss in smallest amniotes
Date: Wed, 10 Feb 2010 07:54:00 -0800 (PST)
Wingspan is one way to measure. That's surface area.
I was considering standing height and volume which is more consistent across
the three smallest flyers.
Question is: Whether or not the smallest pterosaurs were adults or hatchlings,
if they were in the airstream, were they evaporating at a dangerous rate?
--- On Wed, 2/10/10, Jocelyn Falconnet <email@example.com> wrote:
> From: Jocelyn Falconnet <firstname.lastname@example.org>
> Subject: Re: surface/volume ratio and water loss in smallest amniotes
> To: email@example.com
> Cc: "dinosaur mailing list" <firstname.lastname@example.org>
> Date: Wednesday, February 10, 2010, 9:00 AM
> Not so consitent, David
> Birds => 6,5/5 cm for *Mellisuga helenae*, the Bee
> Bats => 16/3 cm for *Craseonycteris thonglongyai*, the
> Hog-nosed Bat or Bumblebee Bat
> Pterosaur => 25/7 cm for *Nemicolopterus crypticus*
> (length estimated
> after a composite reconstruction by John Conway).
> Note also that:
> 1. The Bumblebee Bat is one of the main compettitors for
> the title of
> the world's smallest mammal with the longer but lighter -
> - Etruscan Shrew.
> 2. The holotype of *Nemicolopterus* may be a juvenile
> according to Darren Naish (see Tetrapod Zoology).
> 3. *Nemicolopterus*, if an adult, is quite larger than the
> (especially the wingspan).
> 4. Be small is not a problem at all for winged insects, so
> if there is
> indeed a relation between flight and lower size limit in
> amniotes, it
> should thus be inherent to the animal (metabolism,
> anatomy, reproduction, ...) rather than to flying weather
> 2010/2/10 David Peters <email@example.com>:
> > Speaking of 2/3, 3/4...
> > I ran across this article and a few others like it
> that describe the world's smallest extant amniotes and their
> desiccation troubles whenever removed from their moist leaf
> litter environments.
> > On a similar note, there seems to be a lower size
limit (for adults) for pterosaurs, birds and bats that's
> pretty consistent even though each has different 'surface'
> characteristics. Anyone know of any papers along these
> > Would the lack of smaller birds/bats/pterosaurs be
> more of a flight problem (too small for windy conditions or
> incoming rain drops)?
> > Or a water-loss problem?
> > Baby bats have smaller wings, but embryo pteros do
> not, as we know.
> > Ref below
> > David Peters
> > Caribbean Journal of Science, Vol. 37, No. 3-4,
> 168â€“173, 2001
> > At the Lower Size Limit in Amniote Vertebrates: A New
> > Lizard from the West Indies
> > S. BLAIR HEDGES1 AND RICHARD THOMAS2
> Jocelyn Falconnet
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