Cronopio is an extinct genus of small insectivorous mammal known from the early Late Cretaceous of the Río Negro region in Argentina.

Cronopio is known from the holotype MPCA PV 454, a partial skull around 27 millimetres (1.1 in) long which is missing the skull roof, basicranium and squamosals and from the referred specimens MPCA PV 450, a partial left lower jaw with damaged teeth and MPCA PV 453, an incomplete skull with a relatively complete right lower jaw missing some teeth.

[1] Paleontologist Guillermo Rougier commented on the creature's "superficial" resemblance to the fictional character Scrat in the Ice Age franchise created by Chris Wedge, saying "it just goes to show how diverse ancient mammals are, that we can just imagine some bizarre critter and later find something just like it.

"[2] Cronopio was first named by Guillermo W. Rougier, Sebastián Apesteguía and Leandro C. Gaetano in 2011 and the type species is C. dentiacutus.

[1] Cladogram following the analysis of Rougier, Wible, Beck and Apesteguía (2012):[3] Leonardus Cronopio Necrolestes Reigitherium Peligrotherium Mesungulatum Coloniatherium