Leptoceratopsidae

Extinct family of dinosaurs

Leptoceratopsidae is an extinct family of neoceratopsian dinosaurs from Asia, North America and Europe. Leptoceratopsids resembled, and were closely related to, other neoceratopsians, such as the families Protoceratopsidae and Ceratopsidae, but they were more primitive and generally smaller.

Leptoceratopsidae was originally named by Franz Nopcsa von Felső Szilvás in 1923 as a subfamily Leptoceratopsinae, and its type species is Leptoceratops gracilis. Mackovicky, in 2001, defined it as a stem based taxon and a family consisting of Leptoceratops gracilis and all species closer to Leptoceratops than to Triceratops horridus. The cladogram below represents the results of the phylogenetic analyses performed by He et al. (2015) in their description of Ischioceratops.

Definitive leptoceratopsids have so far been found exclusively in the Late Cretaceous period (late Santonian late Maastrichtian stages) of Asia and Western North America; A possible leptoceratopsid ulna, named Serendipaceratops, has been found in Victoria, Australia. However, a 2010 study showed that it could not be confidently referred to any ornithischian family, and is considered a nomen dubium. Leptoceratopsids range in age from Gryphoceratops, of the late Santonian, to Leptoceratops, right at the end of the Cretaceous in the late Maastrichtian. Gryphoceratops is the first definitive record of Santonian leptoceratopsid. It was named based on a partial left dentary from Alberta, Canada. Gryphoceratops represents the oldest known leptoceratopsid and probably the smallest adult ceratopsian known from North America.