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Re: Cretaceous Pterosaurs



    Allan Smith, you wondered, "Can anyone tell me what the smallest
Cretaceous pterosaur was?"

    In my track studies of the late Early Cretaceous of Maryland, recently
some rather small (compared to the substantially larger ones hitherto found)
pterosaur tracks have been recovered.  In the case of a manus/pes (front
foot/back foot) set, the manus measures 5.3 cm from the claw-tip impression
of digit I to the same of digit III, where the angle of diverication between
those same digits is approximately 81.0 degrees.  In the pes, the spread of
the claw-tip impressions of digits I to IV, is 3.4 cm, with the angle of
diverication being roughly 42.5 degrees.

    I am not experienced enough to give you a highly reliable calculation of
the probable wingspan of the pterosaur that made this set of impressions,
but would guess that it had a wingspan of not less than 60 cm, but possibly
not much greater than 100 cm (1 meter). If anyone out there is more expert,
please correct me.

    Earlier, I recovered an isolated, larger (10 cm long) pterosaur pes
(back foot) impression with a rather different diverication angle (digits I
to IV): 32 degrees.  I believe the pes diverication difference suggests that
a different species of pterosaur was responsible for the larger pes
impression, and that, therefore, we may have had at least two distinct
species of pterosaur in Maryland's late Early Cretaceous.

    Of course, the Maryland pterosaur tracks are from a period too early,
IMHO, for any pterosaur to have been resting upon the back of a Hadrosaur,
per se, but upon the back of an Iguanadon?  Yes.  Ornithopod tracks that
seem to have been made by Iguanadons are found with relative frequency in
the areas involved in my ichnological survey.

    That's the best I can do that might lead to Cretaceous pterosaur size
conclusions; but, it, regrettably, applies to only one part of the
Cretaceous.  I hope this at least provides some help -- even if  'through a
glass darkly' -- for you, Allan.

    Best wishes on your art work.

    Ray Stanford