. . . . . "Paleocene and Eocene Probathyopsis"@en . . . . . . . . "Systematics and evolution of Probathyopsis (Mammalia, Dinocerata) from the late Paleocene and early Eocene of western North America" . "Systematics and evolution of Probathyopsis (Mammalia, Dinocerata) from the late Paleocene and early Eocene of western North America"@en . . . . . . . "From 40 to 65 million years ago" . . . .