feather tracts

["Ken Kinman" <kinman@hotmail.com>]

    The tendency of feathers to grow in tracts is another reason I think
they may have begun on the tail and eventually spread up the back of some
lineages of primitive dinosaurs as they were exapted (for functions other
than predator evasion), and finally up the arms (in "dino-birds").  A
similar development may have occurred in the prolacertiform-pterosaur line
(of which Longisquama is a well-known example).
    If feathers had originally evolved for insulation (of the body and/or
eggs), they would have been more likely to have had a more scattered
distribution (as in the hair of mammals).
                   ------Ken
P.S.  If feathers began on the other end (head) of  dinosaurs and spread
backwards, then perhaps display may have been a more likely original
function.
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