[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

return of the stuffy Ivy-League type



        Having survived three and a half months of Costa Rican rainforest,
I have returned to my native stuffy Ivy-League type institution to once
more do battle with the forces that seek to confuse and mislead us
whenever possible: the dinosaurs. In the meantime, I  have seen spider
monkeys, whales, coatimundis, _Morpho_ butterflies, muscovy ducks,
basilisks darting over a
stream, swallow-tailed kites, armadillos, sloths, caimans, nesting
leatherbacks, a whale and her calf, a treed anteater, quetzals, toucans
and toucanets, army ants and leafcutter ants and acacia ants, dolphins,
giant cerambycid and dynastid beetles, bats and more bats, a tinamou
running from me on its powerful hindlimbs, the obscure insect order
grylloblattodea, cycads and tree ferns, 
the sea quietly on fire with biolumenescence, the world one hundred and
seventy feet below as I stood on the moss and bromeliad-encrusted
uppermost branches of a great strangler fig. 
        All in all, not a bad trip. Managed to learn a bit about dinosaurs and
whatnot down there as well.
        Turns out that the direct light coming down over the
equatorial forests creates a multi-layered forest structure with as many
as five or six strata of vegetation
over any given spot on the ground. This, and an abundance of things to eat
in the canopy and their year-round presence, probably all are
reasons why tropical forests have so many gliding species. So if a
terrorist came up to me and put a gun to my head and forced me to say
wildly speculative things about paleontology (for I would never do so
willingly! ) I would guess that the environment where birds, bats and
pterosaurs evolved, if not a tropical forest, may have resembled one in
many ways.  
        Also, it turns out there are a bunch of large fruits which have
sweet pulps, rock-hard seeds and hard outer coats and not very much to
disperse them. The thought is that these trees have in fact lost their
dispersers: horses, elephants and ground sloths may have been distributing
many of these trees. Curious.
        Saw a lot of bats. Interestingly, they show a great deal of
variation in brachio, uro, and pro-patagium as well as ability to walk on
the ground. Insectivores have a huge uropatagium, frugivores, very little.
A big propatagium is a nectarivore feature, to allow low-speed
maneuverability. Faster bats have longer, narrower brachiopatagia, while
some bats- for example, the biggest microchiropteran, a bird-eating
beast with a three-foot wingspan- have broad wings. I even saw a vampire
take off, it hopped twice and then flapped into the air. It had a very
well-developed thumb and feet, and the uropatagium was almost absent and
the brachiopatagium reduced in attachment to the hindlimbs. It is my
impression that arguing that because Sordes had a uropatagium, all
pterosaurs did, or that because some species lacked one, all pterosaurs
did- as sometimes seems to be the case- is just silly. There's a lot of
variety. Similarly, doubtless some pterosaurs really were almost 
completely unable to use their legs on the ground- but this is the case
with many birds. Some were probably rather capable of movement on the
ground. We can't generalize about an entire group. And I am very skeptical
that pterosaurs were really restricted from forest habitats. If something
with three feet of wing can navigate through the forest, surely some kind
of small pterosaur could.
        As for dinosaurs again- I believe that someone mentioned
some weeks back that there weren't any (possibly) flight-related
features in the ornithomimids. 
        Just for the record, I'd like to say I am not so sure about that.
                ;) 

        -Nick L, 
        Princeton University 
        
        Department of Stuffy, Preppy Ivy-League Studies (e.g. "Beer Pong")