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Re: origin of bats/suspect trees?



David Peters (davidpeters@att.net) wrote:

<If the taxon lists are the same using morphology, the tree results will be the 
same, if you employ at least 150 characters. Thatâs the bottom line. Thatâs 
always been the bottom line. Doesnât matter which characters. Delete 
cranials. Delete post-cranials. Delete axials. Delete every other character, or 
every tenth. If you test like this, youâll see what I mean.>

  This is completely untrue. Try it yourself. Look at various data sets for 
which well over 150 BPs are sampled and separate each gene as a separate 
character group. Run each of these analyses separately for the same taxa, using 
onyl taxa that are shared between the sets. You will not get the same results, 
as the various molecular analyses of birds have shown. Not to mention mammals. 
How do you think they got to the varying positions for various groups in the 
first place?

<Getting back to bats: At least we should be looking for non-volant mammals 
with SOME bat characters, like broad flat ribs,>

  Manatees?

<reduced distal ulna,>

  Most cursorial mammals?

<pedal proportions,>

  Oh, got me there. Bats are kinda in a category to themselves. However, if the 
recent paper on bat finger growth has anything to say, extreme development in a 
short period will completely obliterate proportional constraints in phylogeny. 
No ... proportions are a TERRIBLE platform for comparison.

<wrist fusions,>

  Let's not even go there. Many animals fuse their carpals, but moreover, any 
animal that puts a great deal of stress and strain on the wrist will begin to 
develop carpal anomalies and even develop fusions. Look at moles, birds, etc.

<tooth counts, tooth shapes, etc.>

  Ah, and this is constrained primarily by diet. Dietetically, for example, 
bats and MOLES are highly convergent in dental anatomy, so much so that they 
were allied to the insectivores for this very reason. Genes seem to say 
otherwise. Given that tooth shape and count vary for as basic a reason as jaw 
length, using this as a constraint is a terrible idea. it is also rather 
problematic to compare mammal groups to one another because of their teeth due 
to their convergent nature. It's useful for specific separation, but only 
during in-group comparisons. Sure, you'll get features such as accessory cusps 
in the talonid that are comparable in some taxa, but what about the 
crenellated, blade-like premolars of eutherian dermopterans and the similar 
teeth of non-eutherian multituberculates? Though for the most part the 
similarities end there. Incisiform incisors in kangaroos and rabbits?

  Cheers,