Is Neville's frog Trevor and animagus?

[splnyc]

No: HPFGUIDX 83300

I can't find anywhere this topic has been covered already, but I 
heard that there is a new theory that Neville's frog Trevor could 
actually be Dolores Umbridge? I am re-reading book 5 right now and 
want to check it out again for myself, but could this be true? 
Dolores Umbridge is always described as frog-like and I can't find 
any scenes where Trevor and Dolores are at the same place at the 
same time. Could Dolores be Neville's other grandmother (his 
maternal grandmother, Alice's mother) and perhaps be keeping an eye 
on Neville as his pet frog is SS, CS, PA and GF? Then in OOP we 
don't see Trevor and Umbridge at the same time because Umbridge is 
at Hogwarts and is keeping an eye on Neville in her human form? It 
could even explain why Umbridge wants to deny so much that Voldemort 
is not back - she is still too upset from her daughter's death and 
wants to stay in denial that he could come back. She does not want 
to believe it could be true. This could all be crazy but I was 
curious if anyone out there has heard this or had similar thoughts.