Wyolestes iglesius (Zack, Rose and O'Leary 2025, Early Eocene. USNM 493828) was recently considered a hyaenodont, but the LRT nests Wyolestes with Loxolophus and Ukhaatherium. Both taxa have a long, low skull with a similar dental formula and morphology. Prior authors omitted Loxolophus from Wyolestes analyses. Much of the skeleton is known.

Holotype: UM 67517, a maxilla with roots of P5 and M1 and crowns of M2–3.

Ukhaatherium nessovi (Novacek et al. 1997; Campanian, Late Cretaceous, 80 mya) is known from eight partial skeletons. Wikipedia reports, 4 premolars and 3 molars, but the break in dental shape happens between premolar 3, typically the largest and last one, and the next tooth, molar 1 of 4. The lumbar region is curved. Traditionally considered an Asioryctidae, close to placentals, but with epipubic bones, here it nests at the base of the Metatheria = Marsupialia as a late survivor of that Late Triassic radiation. Loxolophus is a larger relative from after the asteroid impact.

Loxolophus hyattianus (Cope 1885; Early Paleocene, 62mya) was originally considered a raccoon-size condylarth and an ungulate when Arctocyon was included in these clades. Here Loxolophus is a large sister to the Early Cretaceous basal marsupial Ukhaatherium.

Cope EC 1885. The oldest Tertiary Mammalia. American Naturalist 19:385-387.

Novacek MJ, Rogier GW, Wible JR, McKenna MC, Dashzev g D and Horovitz I 1997. Epipubic bones in eutherian mammals from the Late Cretaceous of Mongolia Nature 389: 483-486.

Zack SP, Rose KD and O'Leary MA 2025. New Cranial and Postcranial Remains of the Once Enigmatic Early Eocene Mammal Wyolestes (Mammalia, Ferae, Hyaenodonta) from North America, and Phylogenetic Evidence for its Interordinal Relationships. Bulletin of the American Museum of Natural History 475:1–176.

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