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Re: pterosaurs, bats, flying theropods



A BRIEF REPLY. Greg Paul has not suggested bats were
flying primates, although some scholars have suggested
this (which is nonsense, of course). When I speak of
"intertwined histories", I am speaking not of the
fossil record, but of the ecomorphological
conjurations which have appeared since the early
1800s, when the first pterosaur restorations depicted
them, in effect, as reptilian bats. Kevin Padian,
several years, did a nice paper on these restorations.
Some of what is written below is not germane to what I
was thinking re: the new Kunz/Fenton compendium, and,
reading the comments below carefully, I fail to see
their applicability. I believe the pterosaurs were
driven into extinction by flying dinosaurs, and am
cognizant of the diversity of the pterosaurs by the
end of the Cretaceous. Moreover, for you to state
there were no possible parallel specializations
between pterosaur and theropod diets is something I do
not agree with: snout shape and teeth differences do
not obviate the possibility similar prey may have been
pursued by both flying theropods and pterosaurs. Nor
did I anywhere state there were Cretaceous bats -- the
fossil evidence does not support this. Moreover, the
flying theropods are far more diverse in morphology
than bats, but this does not mean bats do not display
diversity within their limitations.
All in all, Jaime, I read your note with interest, but
am disappointed you "read into" my brief comments
thoughts I did not express, nor would express in the
manner of your extrapolation. I believe, as I wrote,
that bat ecomorphologies, as represented in this
magnificent volume, will shed light on the cluttered
skies at the end of the Cretaceous, when pterosaurs
and flying dinosaurs may have been using some of the
skills bats would later display. I'm afraid, as I've
said, you are exerting yourself a little too much in
argumentation about ideas I neither said in my brief
message, nor say now. However much it pains me to say
it, I believe that pterosaurs may have been more
bat-like than dinosaurs at the end-Cretaceous, and may
have had a similar fascinating array of behaviour
strategies as do bats today. The work of Doris Audet,
Gareth Jones, Donald Thomas, M. Brock Fenton, et al.,
on bat behaviour are, for me, glimmers of inferences
as to what might-have-been with pterosaur behaviour.
No proof, to be sure, but one can use available
ongoing processes to infer the might-have-been.
And so...your letter below is interesting in summation
of your thoughts, but do not reflect mine.
*******************************************************
--- "Jaime A. Headden" <qilongia@yahoo.com> wrote:
> Stephan Pickering (stefanpickering2002@yahoo.com)
> wrote:
> 
> <The intertwined histories (at least, in my mind) of
> theropods,
> pterosaurs, and bats is yet to be untangled.>
> 
>   Of course it hasn't. We have a fossil record to
> deal with. However, some
> points, and the main premise of my reply:
> 
>   Bats, pterosaurs, and birds do not overlap in the
> fossil all together,
> relating no point where all three could interact;
> only birds + pterosaurs,
> and birds + bats ever occur in the same area at the
> same time, never
> pterosaurs + bats. Pterosaurs end at the K/T
> boundary. Birds appear to
> have been limited to shorebird or aquatic varieties,
> being the basal
> clades of birds that have been identified from
> Campano-Maastrichtian
> Cretaceous to Danian Paleocene sediments. The Eocene
> occured well after
> this initial _gasp_ in ecological terms and the
> diversity of birds was
> well on its way. There were no Cretaceous bats that
> we can find, and this
> means no enantiornithine + bat competition so far,
> essentially some of the
> best avian fliers before Ornithurae (the oldest
> members of which being
> able to fly well died out in the Campanian
> [Ichthyornithidae and
> *Apsaravis*]).
> 
> <No doubt, as Greg Paul has suggested, the flying
> theropods drove
> pterosaurs into extinction, and bats (who are NOT
> flying primates,>
> 
>   Like, who has suggested _this_? It's hogwash, I
> tell you, and what Greg
> Paul actually wrote was (begging his pardon): "We
> can 'test' this via a
> thought experiment ... So, while it is possible that
> small pterosaurs
> would have disappeared without the influence of
> avian competition, the
> proposition can be considered dubious, if not
> improbable."
> 
>   No where in the fossil record except for Solnhofen
> and Liaoning do
> pterosaurs and birds exist in the same sediments
> where they are even close
> to the same size, and for about 50 my, there does
> not appear to be a
> decline in diversity in pterosaurs, but rather an
> increase in diversity in
> both birds and pterosaurs. Paul suggested this was
> improbable, but the
> data does not support contention drove small
> pterosaurs out, and this has
> been discussed on the list extensively. For
> competition to occur,
> similarly both groups must have specializations to
> the same diet, but this
> also does not appear to be the case as the snout
> configurations and tooth
> shapes in the various Solnhofen pterosaurs differ
> _very_ widely from that
> of *Archaeopteryx* as well as in Liaoning, the
> wicked teeth of
> *Dendrorhynchoides* are unmatched in similar-sized
> birds, which have
> smaller, triangular snouts. These thought
> experiments say no competition
> appears to have occured which would lead to such
> dwindling or extinction.
> The K/T wiped out apparently _all_ large pterosaurs
> _as well as_nearly all
> flying birds (i.e., enantiornithines, where
> ichthyornithids seems to have
> disappeared previously in the brief exposure of the
> Campanian-early
> Maastrichtian).
> 
> <and have never been secondarily flightless)
> emerged, so to speak, to
> compete with the dinosaurs in the Cenozoic, all
> three clades sharing
> distal airfoils.>
> 
>   Only two of these were in the Cenozoic, and by the
> time the first bat is
> recovered in Eocene sediments, birds have
> diversified into most of the
> present orders, and include many specialized fliers,
> leaving any bat/bird
> competition in the drink, as it were. Other
> arguments seems to focus on
> bats becoming nocturnal, to avoid diurnal birds, but
> this is similarly
> bunk as it is first a generality (only most
> microbats are nocturnal), and
> second there are plenty of diurnal bats (all
> megabats) and nocturnal birds
> (owls, swiftlets, etc.) which live in the same areas
> as microbats. Plus
> parrots and megabats are found in the same regions
> of Africa and South
> America eating nearly the same foods.
> 
> <Theropods differed, of course, in being bipedal:
> their hands and legs
> being, as it were, separate components for
> locomotion, whereas in bats,
> and presumably most pterosaurs, hands + legs were
> the foundations for
> flight mechanisms.>
> 
>   This having nothing to do with bird, bat, or
> pterosaur competition.
> 
> <Dinosaurs, as Greg Paul notes, during the Cenozoic
> to date, are
> surprisingly diverse in morphology, whereas bats are
> not.>
> 
>   Noting this distinct statement, I can see some
> profound rewriting needs
> to occur. Bats, especially the micro kind, are
> _very_ diverse in both
> external morphology, internal anatomy, and skeletal
> morphology. This
> permits them in small areas to specialize among
> several other types of bat
> to types of food. Some take to blod, some to fish,
> some to fruit, some to
> nectar, some to birds. And each one has craniodental
> and wing adaptations
> to suit. Soem bats have a uropatagial muscle from
> the tail to the leg that
> allows them to control the uropatagium tension
> without moving their legs,
> presumably for manuevering. Some have disk-like
> appendages on their arms,
> or a special "slotted" wing, some have elaborate
> pharyngeal/syringeal
> adaptations to producing sound, and some alaborate
> on their facial anatomy
> so much that it has become a joke to be "as ugly as
> a bat." And don't get
> me started about the behaviors. Contentions that
> bats were "not as diverse
> as birds" is a garbage parallel in that bats are
> incredibly diverse, they
> do not need to be as diverse to be either as
> successful or _more_
> successful than birds to be "winners" (look at
> humans, the greatest
> morphological feature we differ in are colorations
> of the skin, hair, and
> eyes, some of which is genetically controlled [eye
> and hair color are
> inherited from your grandparents, essentially], yet
> we are probably one of
> these most successful complex organisms on the
> planet, with tapeworms and
> bacteria and viruses above us, and that's a horrible
> thought -- Bakker
> wrote that it is the unspecialized, undiverse that
> win through, and this
> is _so_ true).
> 
> <But, without stepping on scholarly toes, I suggest
> that bats just might
> give some light on ecomorphologies of the cluttered
> skies at the end of
> the Cretaceous: flight adaptations, vision,
> vocal/chemical signals, etc.
> And, this new book edited by Kunz/Fenton just might
> provide us with
> further extrapolation tools.>
> 
>   Its a sad thing that in the around 15-20 my after
> the Cretaceous when
> the first "true" bat appears, you get statements
> like the above. Hoping
> for a Cretaceous bat simply has no fundamental
> grounds. Noting the 15 or
> so mya that whales became fully aquatic, it is
> easily reasonable that bats
> did not need to be an efficient, flying phenomenon
> in the Cretaceous to be
> anywhere; they would have started out small and
> likely arboreal climbers,
> not super-fliers.
> 
> 
=== message truncated ===


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