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Re: Pterosaur in water



That's a really neat image, Mark. I note in passing that you also said on the website,

....There are also some folk that reckon a sail existed between the crest rami to make a pterosaur-windsurfer, but there is no evidence that such a sail existed. The soft tissue crests of pterosaurs tend to be anchored to rugose and heavily textured bone, but the bone comprising Nyctosaurus's crest is totally smooth, suggesting no soft tissue extension was present.

While I have no argument whatever with your statement, out of curiousity I did once calculate whether Nyctosaurus could have used a sail mounted on that frame to keep itself airbourne while feeding (John Conway did the illustrations). The answer turned out to be yes, given intermittant to near continuous contact of some portion of the animal with the water and given windfields of 7 knots or more (by coincidence, the US Navy estimates the mean annual windfield across the WIS to have been 7 to 8 knots at that time). John and I were always careful to point out that we were just looking at whether such a sail could have been useful IF it existed, and we never postulated that it did actually exist. We gave a talk on this at the annual meeting of the Advanced Physics Society. I still think the sail question is an interesting one, since some other pterosaurs are known to have soft tissue 'sails' configured as crab's claw rigs rather than bermuda rigs, and crab's claw sails function even better than bermudas.
JimC

----- Original Message ----- From: "Mark Witton" <Mark.Witton@port.ac.uk>


There's at least two: check out Fig. 9 in Lockley and Wright's 2003 paper on pterosaur swim tracks, and this old thing:

http://www.flickr.com/photos/markwitton/206037807/in/set-72057594082038974/