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Re: Pterosaur Track Show Bird-Like Landing

Congrats to all the authors on a very nice and worthwhile paper. That said, the press release overemphasizes the "bird-like" angle - the trackway *does* include forelimb prints. The landing includes an initial hindlimb touch and scrape, hop, and forelimb touchdown. The authors describe this all in detail, and liken the initial phase to a bird-like landing, but that's actually not particularly descriptive, because a vampire landing terrestrially also does a 1-2 landing in the same order (see vampires). Bats landing on ceilings do a 1-2 the other way (forelimbs first) in some species, or a yawing 2-point for others (the animal cartwheels to put the feet up).

Despite the fact that the authors use birds as their primary analogy (which is fine), every vertebrate flyer (both powered and unpowered) lands in basically the way described. For birds, the landing is a hindlimb only landing. For ground-moving bats like vampires, the landing is a hindlimb-first landing, followed by assuming a quadrupedal posture (exactly what is seen in the pterosaur track). Even unpowered aerial taxa like "flying" squirrels land in a roughly analogous way - a dynamic stall followed by a 1-2 landing. So, essentially, this trackway is a nice confirmation of what we would already expect. The authors make a rather big deal about the controlled, dynamic stall before landing - while this is a perfectly reasonable thing to discuss in the paper, this is in fact completely unsurprising, as any flying animal larger than a large insect will need to use some kind of controlled stall or hover mechanism to land (the hovering approach really only being applicable to sustained hovering specialists like hummingbirds). Every pterosaur almost assuredly used a dynamic stall before landing - bats do, birds do, and all living unpowered vertebrate gliders (like Draco lizards and gliding squirrels) do so, as well.

So, overall: a solid paper about a great set of tracks that confirms our prior assumptions about pterosaur landing.



Michael Habib
Assistant Professor of Biology
Chatham University
Woodland Road, Pittsburgh PA  15232
Buhl Hall, Room 226A
(443) 280-0181

On Aug 18, 2009, at 10:42 PM, Dann Pigdon wrote:

Pterosaur tracks show it touched down like a bird
New Scientist - 19 August 2009 by Colin Barras

A set of footprints unearthed in France is the first to show one of the winged reptiles coming into land - and suggests they did so in much the same way as most modern birds.

An exceptional set of footprints preserved in 150-million-year-old rock near Crayssac in south-west France holds some answers to pterosaur behaviour. They record the moment a small pterosaur came into land, says Kevin Padian at the University of California, Berkeley.

Padian's team says the prints are similar to those produced by a landing bird. Although most pterosaur tracks show the animals walking on all fours, the first prints in the newly discovered
tracks are of the rear limbs only.

That's because the pterosaur used its wings to "stall" as birds do, says the team, so that the animal's body swung up from a horizontal flight position to near vertical, enabling it to land gently
on its hind feet.

More at:

In Proceedings of the Royal Society B
(Unfortunately the DOI link at the bottom of the article doesn't work)


Dann Pigdon
GIS / Archaeologist                Australian Dinosaurs
Melbourne, Australia               http://home.alphalink.com.au/~dannj