On July 23, Chris Bennett wrote:
The Upper Cretaceous pterosaur record is not very good except for a few
localities, and in my opinion it is not good enough to support the
assertion that pterosaur diversity was reduced or limited to the largest
sizes. A little bit of negative evidence is not very convincing,
especially when one considers how spotty the entire pterosaur record
is. Our knowledge of Lower Cretaceous pterosaur diversity is based in
large part on the nearshore Santana and Greensand deposits, and there is
no comparable Upper Cretaceous nearshore deposit. The non-marine
anurognathids are represented by only about six specimens that are
widely scattered geographically and temporally. It is possible that
there was a diverse nearshore pterosaur fauna in the Upper Cretaceous
right up until the end-Cretaceous extinction, and also possible that the
anurognathids hung on until the extinction.
> >>>>>>>
Chris may be right but a recent cladistic analysis (unpublished) shows
no large gaps in the pterosaur family tree from beginning to end. As in
dinosaurs, I think we can only expect more of the same sorts of
pterosaurs to appear as have already appeared, fitting neatly -- or not
so neatly -- into established clades.
But, just for fun, let's take an alternate approach and try to imagine
what strange
pterosaur morphotypes might be out there waiting to be found.
1. The tree sloth pterosaur: gives up flying for full-time hanging from
tree limbs. Wings diminish or perhaps morph into some kind of
concealment
device. Claws enlarge. Tail prehensile. Rostrum woodpecker-like.
Perhaps
a darting sticky tongue?
2. The vampire pterosaur: finding insects aplenty attracted to
festering
dinosaur wounds, this ptero develops a taste for blood and scabs, then
later creates its own injury sites. Teeth diminish except for twin
fangs.
Claws enlarge to deal with bucking substrate.
3. The hovering nectar-lapping pterosaur: smaller, but with a
proportionately larger pectoralis, this hummingbird-like form is a
sugar
fanatic with a probe-like rostrum and no teeth.
4. The roadrunner pterosaur: gives up flying for full-time terrestrial
locomotion. Wings diminish. Legs lengthen. Accessory membranes provide
heat sinks trailing major muscles.
5. Bat-like pterosaur: Nocturnal. Cave-dweller. Large eyes (rather than
ears). Able to fold wings compactly at mid-digit. Hangs inverted
quadrupedally, a trick learned during infancy while clinging to its
mother
holding on to her neck with pedes especially modified with a longer
fourth
digit and tiny claws. Grabs aerial insects in wide mouth or as part of a
jai-alai maneuver using one wing membrane.
>
6. Bird-of -paradise pterosaur: Supreme show-off. Extremely long wings
swing in counter rhythm to the elevated tail vane, alternately
revealing
and concealing the hyper-plume soft head crest.
7. Floating bottom-feeder: Unable to sink, this bottom-probing pond
floater finds food farther from shore by developing a longer rostrum and
neck -- plus it grows to enormous dimensions.
8. Sparrow-like pterosaur: small, brown, common. Gives rise to most of
the above.
9. Your turn. Add some more.
: )
David Peters