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New Pterosaur Articles



J Evol. Biol. 2007 May;20(3):1230-6. 
A morphospace-based test for competitive exclusion
among flying vertebrates: did birds, bats and
pterosaurs get in each other's space?
McGowan AJ, Dyke GJ.
Department of Palaeontology, Natural History Museum,
London, UK. a.mcgowan@nhm.ac.uk

Three vertebrate groups - birds, bats and pterosaurs -
have evolved flapping flight over the past 200 million
years. This innovation allowed each clade access to
new ecological opportunities, but did the
diversification of one of these groups inhibit the
evolutionary radiation of any of the others? A related
question is whether having the wing attached to the
hindlimbs in bats and pterosaurs constrained their
morphological diversity relative to birds. Fore- and
hindlimb measurements from 894 specimens were used to
construct a morphospace to assess morphological
overlap and range, a possible indicator of
competition, among the three clades. Neither birds nor
bats entered pterosaur morphospace across the
Cretaceous-Paleogene (Tertiary) extinction. Bats plot
in a separate area from birds, and have a
significantly smaller morphological range than either
birds or pterosaurs. On the basis of these results,
competitive exclusion among the three groups is not
supported.

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 J Evol Biol. 2007 May;20(3):1164-70. 
Cope's Rule in the Pterosauria, and differing
perceptions of Cope's Rule at different taxonomic
levels.
Hone DW, Benton MJ.
Department of Earth Sciences, University of Bristol,
Bristol, UK. d.hone@lrz.uni-muenchen.de

The remarkable extinct flying reptiles, the
pterosaurs, show increasing body size over 100 million
years of the Late Jurassic and Cretaceous, and this
seems to be a rare example of a driven trend to large
size (Cope's Rule). The size increases continue
throughout the long time span, and small forms
disappear as larger pterosaurs evolve. Mean wingspan
increases through time. Examining for Cope's Rule at a
variety of taxonomic levels reveals varying trends
within the Pterosauria as a whole, as pterodactyloid
pterosaurs increase in size at all levels of
examination, but rhamphorhynchoid pterosaurs show both
size increase and size decrease in different analyses.
These results suggest that analyses testing for Cope's
Rule at a single taxonomic level may give misleading
results.

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J Exp Biol. 2007 May;210(Pt 10):1663-71. 
Sailing the skies: the improbable aeronautical success
of the pterosaurs.
Wilkinson MT.
Department of Zoology, University of Cambridge,
Downing Street, Cambridge CB2 3EJ, UK. mtw21@cam.ac.uk

Pterosaur wings bore a striking resemblance to sails,
having a bony spar at the leading edge, formed by the
forelimb and one enormously elongated digit, and an
elastic wing membrane. Such simple wings would be
expected to have performed badly due to excessive
deformation, membrane flutter and poor control
characteristics. Here I discuss how certain anatomical
features, specifically a forewing membrane in the
inner part of the wing and a system of fibres embedded
in the distal part, may have countered these
shortcomings. The forewing, supported by the unique
pteroid bone, would have reduced the wings' geometric
twist, and has been shown in wind tunnel tests to
improve membrane stability at low angles of attack and
dramatically increase the maximum lift coefficient at
high angles of attack. The function of the fibres is
poorly understood, but it is suggested that they
improved membrane stability and optimised twist nearer
the wingtips.