[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Ichthyosaur breathing



Surfing the web I came across this website of a rough draft regarding
ichthosaur breathing by Richard Cowen, UC-Davis.

http://www-geology.ucdavis.edu/~cowen/ichthyosaur.html

In short Cowen discusses breathing in various types of reptiles then
discusses the possibilities for ichthyosaurs and suggests the following:

"Ichthyosaurs are not penguins or dolphins, but it is possible that
leaping could provide yet another way to avoid Carrier's Constraint.
An ichthyosaur could swim at high speed in an undulating path, with the
pectoral fins providing upward or downward forces as needed. With
appropriate control, the ichthyosaur could "porpoise", lifting clear of
the water, pointing straight ahead, and in that position could breathe
at high speed, exactly as Hui's penguins did."

That doesn't strike me as practical as the following, which Cowen
mentions earlier in the text, which he then overlooked as a possibility
for ichthyosaurs:

"Sea snakes have avoided Carrier's Constraint by reducing one lung: with
only one effective lung, the constraint disappears."

...especially since ichthyosaurs did reduce their limbs and increase
their vertebral count early in their history.

Any thoughts?

David Peters
St. Louis