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Re: tiny dinosaur



Ronald Orenstein <ron.orenstein@rogers.com> wrote:


> Actually gliding evolved at least four times in living mammal groups: flying
> squirrels, gliding possums (possibly more than once in this lineage), African
> anomalurid rodents and Dermapterans (colugos)



To my knowledge, gliding behavior has arisen no less than eight times
in crown mammals.  Extant gliding mammals include colugos ("flying
lemurs"; Cynocephalidae); certain phalangeroid diprotodont marsupials
(Petauridae, Acrobatidae, _Schoinobates_ - gliding likely acquired
independently by each); and two extant rodents groups, flying
squirrels (Petauristinae) and scalytails (Anomaluridae).


In the fossil record, there are two other kinds of gliding rodents:
_Eomys quercyi_ (Eomyidae) from the Oligocene, the earliest known
gliding rodent; and a gliding dormouse (_Glirulus_ sp.) from the
Miocene.


Additionally, as Ron noted, there is _Volaticotherium_ (Jurassic?), a
furry glider that lies outside the crown mammal clade.  So that's nine
times for mammaliaforms.


For a long time, the fossil paromomyids (Plesiadapiformes) were
thought to have been gliders; but later studies on the postcranial
proportions of this group undermined the interpretation of paromomyids
as gliders.





Cheers

Tim