Leptoceratopsids represent an earlier, more lightly built branch of the horned-dinosaur lineage than the large, quadrupedal Ceratopsidae. Most genera retained the ability to walk bipedally, at least some of the time, and lacked the prominent horns and elaborate frills that define their larger, more famous relatives -- instead carrying a modest bony frill and a beaked skull that hints at the direction the lineage would later take.
Leptoceratops, the genus that names the family, is known from Late Cretaceous North America and survived alongside much larger ceratopsids like Triceratops, illustrating that the more basal, smaller-bodied branch of the ceratopsian family tree persisted right up to the end of the Cretaceous rather than being replaced entirely by its larger cousins.