[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
<<Betty's right: what I was actually referign to was a big brown bat;
what I first thought of as a megachiropteran appears to be a very
large microchiropteran, which small ears and a very unmodified nose
(it looked like a megachiropteran, just very small and the head does
look similar to micros), and I don't know much of the differences
between the two groups. Matt's refs on mirco polyphyly may have
something to say, but anyway, I have only a few things on bats, and
most of these are on micros. Sorry.>>
Microchiropteran polyphyly has been suggested, yes, but I usually talk
about CHIROPTERAN diphyly. That is, the controversy over whether or not
Megachiroptera+Microchiroptera form a monophyletic group. John
Pettigrew has been the most vocal on this issue, basing his arguments on
the fact that megabats and primates (including the colugo) share several
(a few dozen) nervous system specializations not found in microbats.
Bat diphyly is nothing really new; Hill and Smith have suggested this
many times during the 70s (again, shared characters between megabats and
primates not found in microbats; this time penial characters). Also,
there is some molecular evidence that supports diphyly in bats. All in
all, I think that the case for bat diphyly is pretty strong, but it
needs more osteological and myological data, something that proponents
of bat monophyly have.
How do you tell a megabat from a microbat? Its relatively easy. Most
megabats are relatively large, while microbats are for the most part,
very small (certain cryptozoologists believe that there are some
microbats with 3 meter wingspans; I don't buy it for a second).
Megabats have a claw on the index finger, while extant microbats lack
it. Megabats hang from branches colugo-style, using forelimbs and
hindlimbs, while microbats use only hindlimbs. Microbats frequently
nest in large colonies in the deep recesses of caves, while megabats,
excluding some species of _Rousettes_, _Dobsonia_, etc (these bats only
nest around the entrance of caves in not in large groups), tend to stray
away from caves, preferring trees. Megabats universally have large eyes
that they use to navigate with, while microbats have small eyes.
Megabats do not have a specialized ear structure, while microbats
usually have a very complicated ear with a tragus and antitragus in the
caudal portion. Megabats also tend to be more 'cute', while many
microbats, especially those with noseleafs, tend not to be. Except for
some species of _Rousettes_, megabats do not employ echolation (note
that the megabat species with echolation use a echolation form that is
considered non-homologous to the form that microbats use); microbats,
except for some extremely abberent species, use echolation. Megabats
are universal frugivores and nectorivores, while except for some South
American microbats, microbats do not have anything to do with flowers.
There are a lot more characteristics for each group (such as locomotion,
more diet stuff, geography, parental care, dentition, reproduction,
etc.) but I will give you this list to finish with.
Get Your Private, Free Email at http://www.hotmail.com