Baiotomeus is a genus of mammals from the extinct order of Multituberculata. It is known from the Paleocene of North America.
The genus Baiotomeus was formally named by Krause in 1987 (Krause, 1987), and has also been known as Mimetodon (partly), Neoplagiaulax (partly), and Ptilodus (partly).
Baiotomeus douglassi is a fairly substantial multituberculate weighing almost 200 g. Remains have been found in the Fort Union Formation of Montana and Porcupine Hills Formation of Alberta, Canada. The holotype specimen hails from Wyoming in the United States, in strata of the Gidley Quarry dated to the Torrejonian stage of the Paleocene.
The species was originally named Ptilodus douglassi by Simpson in 1935 (Simpson, 1935), but it has been reclassified several times:
It was finally assigned to Baiotomeus by Hartman in 1986 — which is before Krause formally established the genus in 1987.
Remains of Baiotomeus lamberti have been discovered in Montana in the United States, in the Medicine Rocks of the Tongue River Formation, which have been dated to the Paleocene.