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

Re: Lemurs and Feathers



David Marjanovic (david.marjanovic@gmx.at) wrote, in reply to
Dan Bensen:

  DAN:

<<So bats and pterosaurs evolved from swimmers, too? Or is it
ony birds that required a swimming stage to develop flight?>>

  DAVID:

<Ebel indeed considers all long-tailed pterosaurs (and
*Archaeopteryx*) to have been underwater fliers capable of only
limited aerial flight (due to the center of gravity lying too
far behind). He also writes that, IIRC, "the arboreal origin of
bat flight is questionable". Of course, I have to consider
myself even less of an expert on pterosaurs, let alone bats,
than on birds; however, bats (and, to variable amounts,
pterosaurs) at least have what I'd expect in a
glider-descendant, i. e. a patagium that runs from the arms to
the legs and between the legs, rather than wing feathers
attached only to the hands and forearms.>

  ME:

  Sorry if this is crude, but we're supposed to think here, when
data is presented before us. And I don't know how Ebel formed
this concept, but rhamphorhynchs had quite cranially located
CG's between the shoulders or just behind. The form of the trunk
is telling in this, and rhamphorhynchs especially have very
short hindlimbs, suggesting compensation for increase
arboreality. Nothing mechanical in the forelimb suggest the limb
was used to scull or flap in water. It's is supremely adapted
for _aerial_ flight.

<Flying insects probably did evolve from swimmers. See Pat
Shipman: Taking Wing and a Nature paper that I can't find now,
perhaps I haven't copied it.>

  Irrelevant to vertebrate flight. Arthropods went airborne
presumably before they went terrestrial, whereas vertebrates
were terrestrial then went airborne.

=====
Jaime A. Headden

  Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
  Where the Wind Comes Sweeping Down the Pampas!!!!

__________________________________________________
Do You Yahoo!?
Get personalized email addresses from Yahoo! Mail
http://personal.mail.yahoo.com/