The specific name, cilinskii, honors Juan Cilinski, a local rancher who helped with the fieldwork that led to the discovery of Coloniatherium.

[3] The first molar has three roots, a trait shared only with Leonardus from the approximately contemporaneous Los Alamitos Formation of Argentina among dryolestoids.

[4] The petrosal of Coloniatherium appears to be similar in terms of phylogenetic position to Vincelestes, an Early Cretaceous Argentinean mammal, but also share some apparently derived traits with therians (i.e., marsupials, placentals, and relatives).

The formation includes fluvial (river), deep-sea, and near-shore deposits, and the mammalian fauna probably comes from an estuary, tidal flat, or coastal plain.

[1] La Colonia Formation also contains dryolestoids, such as Coloniatherium and Reigitherium, as well as the enigmatic possible multituberculates Argentodites and Ferugliotherium.