Re: A Wild Hare [not dino related]

[Michael Habib <mhabib5@jhmi.edu>]

> Long answer:  Recent molecular studies have thoroughly refuted the 
> hypothesis that bats are diphyletic, with megabats closer to primates. 
>  Last I heard, molecular evidence was even indicating that 
> Microchiroptera is actually paraphyletic with respect to 
> Megachiroptera...

Specifically, megachiroptera come out near Rhinolophoids (if memory 
serves).  That's additionally interesting given that Rhinolophoids have 
a distinct echolocation system from other microchiropterans.  Since 
it's not dinos, I'll leave it at that.  Those that would like refs on 
flight and echolocation differences between Rhinolophoids and other 
microchiropterans can contact me off-list (I have a number on hand).


> > 1. Do eurymlids have a large diastema like Gomphos, lagomorphs and 
> > rodents do?
>
> Not familiar with them.

I think they have some kind of diastema; mimotonids have a larger one, 
if I remember correctly (Mimotonids may be a lagomorph sister taxon).

> Not really.  Highly related to food processing; diastemata appear to 
> have arisen many times among mammals.

True, they do pop up a lot.  I've heard a few different thoughts on why 
diastema appear, but personally I suspect a particular pairing of 
mechanical advantages selects for diastema.  Specifically, if an animal 
is combining a few teeth for snipping with a few sets of teeth for 
crushing, it derives significant mechanical advantage from putting the 
crushing teeth near the fulcrum (for high force) and the snipping teeth 
far from the fulcrum (for control).  But that requires space between 
the two sets; hence a diastema.  Just a thought.

Cheers,

--Mike Habib