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Re: Pterosaur take-offs explained (pdf link)

From: Ben Creisler

Just in case this link has not been posted yet:


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.