Deltatherium fundaminis (Cope 1881, middle Paleocene 60 mya, 14 cm skull length, cat-sized, AMNH 16610) this former creodont and former tillodont nests with Prodinoceras, a basal creodont. The large cranial crest anchored large jaw muscles.

Wikipedia reports, "its relatives are far from clear."

Trigonostylops wortmani (Ameghino 1897; Late Paleocene—Early Eocene; est. 1.5m) nests apart from the astrapotheres, close to Prodinoceras. The premolars were molarized. The snout remains unknown.

Prodinoceras martyr (Matthew, Granger and Simpson 1929, Late Paleocene, 2.9 m long) is traditionally considered the most basal uintathere. In the LRT it nests between Trigonostylops and the much smaller Apterodon.

Achaenodon robustus (Cope 1873, Eocene) was tradionally considered an artiodactyl, but here nests with the notoungulate, Thomashuxleya, only larger. The skull was extremely wide with strong jaw muscles filling the space around the narrow cranium and crests.