Question: How old is the fossil record of the order that contains the only strictly marine herbivorous mammal?
Sentence (from "Xenastrapotherium"): "Xenastrapotherium" (named after the Greek word "xenos" "strange" add to the genus "Astrapotherium", "lightning beast") was a genus widely distributed in northern South America, in contrast to other species of astrapotheres which lived in the area of the Southern Cone of the continent.
Relevant evidence: No