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Re: Pterosaur take-offs explained (pdf link)
From: Ben Creisler
bh480@scn.org
Just in case this link has not been posted yet:
http://www.plosone.org/article/info%3Adoi%2F10.1371%
2Fjournal.pone.0013982
Witton MP, Habib MB (2010)
On the Size and Flight Diversity of Giant Pterosaurs, the
Use of Birds as Pterosaur Analogues and Comments on
Pterosaur Flightlessness.
PLoS ONE 5(11): e13982. doi:10.1371/journal.pone.0013982
The size and flight mechanics of giant pterosaurs have
received considerable research interest for the last
century but are confused by conflicting interpretations
of pterosaur biology and flight capabilities. Avian
biomechanical parameters have often been applied to
pterosaurs in such research but, due to considerable
differences in avian and pterosaur anatomy, have lead to
systematic errors interpreting pterosaur flight
mechanics. Such assumptions have lead to assertions that
giant pterosaurs were extremely lightweight to facilitate
flight or, if more realistic masses are assumed, were
flightless. Reappraisal of the proportions, scaling and
morphology of giant pterosaur fossils suggests that bird
and pterosaur wing structure, gross anatomy and launch
kinematics are too different to be considered
mechanically interchangeable. Conclusions assuming such
interchangeability?including those indicating that giant
pterosaurs were flightless?are found to be based on
inaccurate and poorly supported assumptions of structural
scaling and launch kinematics. Pterosaur bone strength
and flap-gliding performance demonstrate that giant
pterosaur anatomy was capable of generating sufficient
lift and thrust for powered flight as well as resisting
flight loading stresses. The retention of flight
characteristics across giant pterosaur skeletons and
their considerable robustness compared to similarly-
massed terrestrial animals suggest that giant pterosaurs
were not flightless. Moreover, the term ?giant pterosaur?
includes at least two radically different forms with very
distinct palaeoecological signatures and, accordingly,
all but the most basic sweeping conclusions about giant
pterosaur flight should be treated with caution.
Reappraisal of giant pterosaur material also reveals that
the size of the largest pterosaurs, previously suggested
to have wingspans up to 13 m and masses up to 544 kg,
have been overestimated. Scaling of fragmentary giant
pterosaur remains have been misled by distorted fossils
or used inappropriate scaling techniques, indicating that
10?11 m wingspans and masses of 200?250 kg are the most
reliable upper estimates of known pterosaur size.