[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Dinosaurs and birds
Anthony Docimo writes:
could maniraptors (not birds) with feathered arms have had an advantage
over maniraptors lacking feathers on their arms, when it comes to those
turning manuvers and clearing obstacles?
Another advantage of 'winged' forelimbs in a fast runner would be to help
streamline the folded forelimbs into the body wall to reduce drag. In this
instance the 'wings' would be kept tightly folded while running.
Many extant animals go through an arborial phase as juveniles, which they
grow out of (Komodo monitors come to mind). I envisage the juveniles of some
dromaeosaurs (like *Saurornithosaurus*) spending a lot of time in trees,
avoiding larger predators and perhaps chasing small arborial prey. The
recurved second toe would have made a handy grapple, while relatively large
forelimb proportions and low body mass could even have made them semi-volant
(or at least capable of parachuting in case of a fall). Upon reaching adult
size, they could have switched to a more cursorial lifestyle, in which the
forelimbs (and perhaps 'wing' fans) were too small for flight (or even
gliding), and were perhaps used in the manner I suggested earlier (and as
display and/or brooding devices). The recurved toe claws could have then
functioned more as predatory tools than for climbing.
The question would then be whether such behaviour resulted in some early
maniraptor lineages becoming paedomorphic and retaining volancy their entire
life (eventually becoming 'birds'), or whether such behaviour was a case of
ontogeny recapitulating phylogeny (ie. flight being ancestral to
dromaeosaurs, and being reflected in their juvenile stage).
GIS / Archaeologist http://www.geocities.com/dannsdinosaurs
Melbourne, Australia http://heretichides.soffiles.com