Genus: Coloniatherium ROUGIER, FORASIEPI, HILL & NOVACEK, 2009
Etymology: Colonia, after Siera de La Colonia, Chubut Province, Patagonia, Argentina and the homonymous Formation, where the fossils were found, and Greek, therium, "therion"; meaing beast or animal, a common suffix for mammalian taxa.

Species: cilinskii ROUGIER, FORASIEPI, HILL & NOVACEK, 2009
Etymology: In honor of Mr. Juan Cilinski, a local rancher who provided great support to our field efforts while working at El Unguayo.

Holotype: MPEF-PV 2087

Locality: El Uruguayo, 43°06'18.8"S, 67°41'45.3"W, Estancia El Pino, belong the to Avila Family, Sierra de La Colonia, Chubut Province, Patagonia, Argentina.

Horizon: Upper part of the La Colonia Formation.


Age: Campanian Stage-Maastrichtian Stage, Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material: Fragmentary right lower jaw iwht complete p3, root fragments of p2, m1-m3, and alveoli for p1 and double rooted canine.

Referred material:

MPEF-PV 2011: Left m1.

MPEF-PV 2059: Right p2.

MPEF-PV 2063: Right m2.

MPEF-PV 2064: Left m1..

MPEF-PV 2066: P1.

MPEF-PV 2070: Left C.

MPEF-PV 2073: Left p3.

MPEF-PV 2078: Left M1, right p3.

MPEF-PV 2079: Left P3.

MPEF-PV 2081: Right P3.

MPEF-PV 2085: Fragmentayr right lower jaw iwth very worn remants of m1-m3 in situ, and alveolus for p3.

MPEF-PV 2088: Right P2.

MPEF-PV 2090: Right p2.

MPEF-PV 2091: Left m2.

MPEF-PV 2092: Left m3.

MPEF-PV 2100: Right P2.

MPEF-PV 2103: Left P2.

MPEF-PV 2104: Fragmentary lower jaw with worn down p1 and p2.

MPEF-PV 2137: Left m3.

MPEF-PV 2142: Right P3.

MPEF-PV 2148: Right p2

MPEF-PV 2163: Right M3.

MPEF-PV 2183: Left M2.

MPEF-PV 2192: Fragmentary jaw with partial caninae.

MPEF-PV 2203: Left m3.

MPEF-PV 2223: P1.:

MPEF-PV 2260: Right M1.

MPEF-PV 2299: Right m2.

MPEF-PV 2300: Right M3.

MPEF-PV 2301: Left P2.