sciuromorpha

from WordNet (r) 3.0 (2006)

Sciuromorpha
    n 1: large more or less primitive rodents: squirrels; marmots;
         gophers; beavers; etc. [syn: {Sciuromorpha}, {suborder
         Sciuromorpha}]

from The Collaborative International Dictionary of English v.0.48

Sciuromorpha \Sci`u*ro*mor"pha\, n. pl. [NL., fr. L. sciurus
   squirrel + Gr. morfh` form.] (Zool.)
   A tribe of rodents containing the squirrels and allied
   animals, such as the gophers, woodchucks, beavers, and
   others.
   [1913 Webster]