LACM 149371 (Natural History Museum of Los Angeles County specimen 149371)[1] is an enigmatic fossil mammalian tooth from the Paleogene (66 to 23 million years ago, mya) of Peru. It is from the Santa Rosa fossil site, which is of uncertain age but possibly late Eocene (55 to 34 mya) or Oligocene (34 to 23 mya). The tooth is poorly preserved and may have been degraded by acidic water or because it passed through a predator's digestive tract. Its largest dimension is 2.65 mm. It is triangular in shape and bears six cusps that surround the middle of the tooth, where there are three basins (fossae). Crests connects the cusps and separate the fossae. The microscopic structure of the enamel is poorly preserved.
LACM 149371 was described in 2004 by Francisco Goin and colleagues, who tentatively interpreted the tooth as a left last upper molar. Although they saw similarities with South American ungulates, some early rodents, and multituberculates, they believed the tooth was most likely of a gondwanathere. Among gondwanatheres—a small and poorly known group otherwise known from the Cretaceous through Eocene of some of the southern continents (Gondwana)—they thought the Cretaceous Argentinian Ferugliotherium to be the most similar.