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Lemurs and Feathers
Two interesting facts have coincided to make me think hard once again
about the origin of feathers, and in a way corroborate once again my
Mick Ellison has been kind enough to send me a full digital study of
Norell's Yulong the feathered wonder, and it had excellent pictures of
the feathers (or protofeathers). I was amazed by the detail but above
all the clear difference of the strands and tuffs as distributed in
different parts of the body. You have stiff strands, you have hairy
strands some are matted together, some are not. Some are long quills
with barbules. Some are simply hair. There are even different varieties
of quills and the way they are organized .
At the same time I was browsing the very good "Los Dinosaurios
Voladores" (The Flying Dinosaurs) by Jose Luis Sanz ( I recommend this
little book to all of you brave enough to read Spanish science texts).
Having a quick read I came about to several pictures of the hardening
hair strands of the genus of the lemur Propithecus based on Feduccia
(93). These matted, hardened tuffs of hair around the arms and legs
help the animal to 'fly' from tree to tree.
Looking closely to the photographs I couldn't help but noticing how
similar were the lemur hardened hair strands to some of Yulong's
integumentary structures (and for that matter, even to
Sinosauropteryx!). Following this lead and Richard Prum's paper on the
origin of feathers, I'm concluding once again that indeed hairy or
branched integument was first (that is, all ancestral dinosaurs must
have been 'hairy' at some stage) and single (or several broom-like)
thicker quills sporting barbules evolved in arboreal forms to hold the
strands together and perfect the 'parachuting' effect. Fully formed
feathers are just the last stage in this development. Whatever animal
had fully formed feathers must have been a descendant of fully volant or
sophisticated parachuting forms. From lemur-like protodinosaurs to
birds seems almost easy.
This of course leaves out of my mind once again (no big news) any
fanciful stuff about protofeathers having been at some stage something
like Longisquama-like scales.
Jose Luis Sanz is adamant about the ground-up origin of flight and
supports it almost in every page of the book. But, until anyone comes
with a really better argument, is still trees-down for my eyes!
The scenario gets more complicated as we go back in dinosaur
evolution... but that is a matter of further discussion.
Visit my website on http://www.ndirect.co.uk/~luisrey