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344 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
ecological conditions of say, an arboreal habitat, is not really
justified. It has been pointed out that there are different elevated
objects in the environment, not just trees, that can be used to
provide gravitation as a source of acceleration for getting up
speed and gaining lift. Therefore, I think this dichotomy, this
contradistinction, between an arboreal and terrestrial origin of
flight is not really justified. I think we should first discuss the
gliding model then the cursorial model. These should be considered
separately. Following this, if we come to the conclusion,
as many have, like Jeremy Rayner [1991], who knows a
lot more about this than I do, that the gliding model is aerodynamically
much more likely than the cursorial model, we can
evaluate the data to see if this model is supported ecologically.
But we should not start out with the arboreal versus the cursorial
theory per se; this is simply misleading."
Peter Wellnhofer concluded the afternoon's discussion with
a plea for putting Archaeopteryx into the perspective of an
evolved flyer, not as the first bird. His thoughtful comment
was: "The focus of our discussion here has centered around the
abilities of Archaeopteryx—as an animal could it climb, could
it mn, how fast, et cetera? I think these issues are not so important.
The early origin of flight happened well before, much earlier
than the evolution of Archaeopteryx. We must not compare
the life style of Archaeopteryx—i.e., the environment, the hab­
Chiappe, L.M.
1995. The First 85 Million Years of Avian Evolution. Nature, 378:
349-355, 6 figures.
Ostrom, J.H.
1974. Archaeopteryx and the Origin of Flight. Quarterly Review of Biology,
49:27-47, 10 figures.
Paul, G.
1988. Predatory Dinosaurs of the World. 464 pages. New York: Simon
and Schuster.
Rayner, J.M.V.
1991. Avian Flight Evolution and the Problem of Archaeopteryx. In
J.M.V. Rayner and R.J. Wooton, editors, Biomechanics in Evolution,
pages 183-212, 6 figures. Cambridge: Cambridge University
Press.
Literature Cited
itat. It doesn't matter whether there were trees or not; these are
absolutely unimportant in the present context. Even if Archaeopteryx
could climb trees, it doesn't change the general bauplan
of the skeleton of Archaeopteryx, which is a bauplan for
bipedal mnning. What is displayed in Archaeopteryx is a later
adaptation in the direction of climbing flight."
Concluding Remarks
While listening to the various points raised and discussed in
this roundtable, one could not help but be reminded of the
Eichstatt conference on Archaeopteryx held 12 years ago in
1984. Have our opinions about the origin of flight changed
since then? If so, in what way? In my estimation, some
progress has been made in that the participants seemed not only
willing to consider views at odds with their own but were anxious
to entertain new information and approaches. I believe
many of us are guardedly optimistic about the promise of new
insights into the question of the origin of flight in birds, aided
by the additional specimens of Archaeopteryx unavailable to us
12 years ago and by the recent additions to our database of a series
of Cretaceous fossil birds (for a review, see Chiappe,
1995).
Russell, D.A., and Zhi-Ming Dong
1993. A Nearly Complete Skeleton of a New Troodontid Dinosaur from
the Early Cretaceous of the Ordos Basin, Inner Mongolia, People's
Republic of China. Canadian Journal of Earth Sciences, 30:
2163-2173, 3 figures.
Vazquez, R.J.
1992. Functional Osteology of the Avian Wrist and the Evolution of Flapping
Flight. Journal of Morphology, 211:259-268, 5 figures.
Yalden, D.W.
1985. Forelimb Function in Archaeopteryx. In Max K. Hecht, John H. Ostrom,
Gunther Viohl, and Peter Wellnhofer, editors, The Beginnings
of Birds, Proceedings of the International Archaeopteryx Conference,
Eichstatt, 1984, pages 91-97, 4 figures. Eichstatt: Freunde des
Jura-Museums, Eichstatt.