Rabbit? Gopher? Lagomorph?

[Sacha]

I'd appreciate a little help with an ID and perhaps clearing up some confusion I'm having with Lagomorphs. A couple weeks ago I posted this photo which was verified as a lagomorph which, for some reason, I assumed was rabbit (although it closely resembled pocket gopher in Hulbert's book). I found this in Florida's Santa Fe.

 

 

The peg like teeth were diagnostic.

 

Yesterday I went to the Peace River and found this little (1/2" x 1/2") piece of maxilla (?) with 3 molars in it.

 

 

 

These teeth resemble Jackrabbit teeth in another photo in Hulbert's book.

 

1) Is the first fossil identifiable to rabbit or Pocket Gopher or only to Lagomorph?

2) Is the 2nd fossil Lagomorph?

3) Is the 2nd fossil identifiable beyond Lagomorph?  

 

Thanks allot.  

[doushantuo]

I am posting this here,because it SEEMS logical.

https://peerj.com/articles/2453.pdf

The occlusal surface of the teeth is more informative

 

[Batfossil]

The first appears to be a good gopher, though it's hard to make out the photo. The anterior tooth should consist of two lophs and the next of one (see the photo). The second looks like lagomorph, but the photo is difficult to make out (too dark).

 

[Batfossil]

Hit the button too soon. The second looks like a bit of the dentary; each tooth should consist of two lophs (also true of the posterior teeth of the maxilla). With the material you have, size is going to be about all you have to go on--smaller for cottontail, larger for jackrabbit.

[Fossildude19]

[doushantuo]

Guessing it's a Thomomys of some kind(and it looks geomyid anyway)

[Sacha]

Excellent! I appreciate it. 

[Batfossil]

Definitely geomyid, but I think more likely Geomys than Thomomys. I've lightened up the photo (on right) and the p4 and m1 appear to be Geomys-like (see left fossil specimen in left photo) than Thomomys-like (right specimen). In Geomys (and Cratogeomys) the first molar (second cheek tooth in the original) is oval and the first loph of p4 relatively large and connected to the posterior loph by a nearly parallel-sided bridge, unlike in Thomomys; in Thomomys, the first molar is thickened on the lateral side.