A genus with intermediate horns, "Soergelia", inhabited Eurasia in the early Pleistocene, from Spain to Siberia, and crossed to North America during the Irvingtonian (1.8 million years to 240,000 years ago), soon after "Euceratherium". Unlike "Euceratherium", which survived in America until the Pleistocene-Holocene extinction event, "Soergelia" was a lowland dweller that disappeared fairly early, displaced by more advanced ungulates, such as the "giant muskox" "Praeovibos" (literally "before "Ovibos""). The low-horned "Praeovibos" was present in Europe and the Mediterranean 1.5 million years ago, colonized Alaska and the Yukon one million years ago and disappeared half a million years ago. "Praeovibos" was a highly adaptable animal that appears associated with cold tundra (reindeer) and temperate woodland (red deer) faunas alike. During the Mindel glaciation 500,000 years ago, "Praeovibos" was present in the Kolyma river area in eastern Siberia in association with many Ice Age megafauna that would later coexist with "Ovibos", in the Kolyma itself and elsewhere, including wild horses, reindeer, woolly mammoth and stag-moose. It is debated, however, if "Praeovibos" was directly ancestral to "Ovibos", or both genera descended from a common ancestor, since the two occurred together during the middle Pleistocene. Defenders of ancestry from "Praeovibos" have proposed that "Praeovibos" evolved into "Ovibos" in one region during a period of isolation and expanded later, replacing the remaining populations of "Praeovibos".