Chaoyangsauridae is a
family
Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
of
ceratopsia
Ceratopsia or Ceratopia ( or ; Ancient Greek, Greek: "horned faces") is a group of herbivore, herbivorous, beaked dinosaurs that thrived in what are now North America, Asia and Europe, during the Cretaceous Period (geology), Period, although ance ...
n
dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...
s. They are among the earliest known
marginocephalian dinosaurs, with remains dating to about 160 million years ago, during the Late
Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...
period. Members of this group had sharp beaks for snipping off leaves to eat, and a very small frill.
This family is officially defined in the ''PhyloCode'' as "the largest clade containing ''Chaoyangosaurus youngi'', but not ''Psittacosaurus mongoliensis'' and ''Triceratops horridus''".
Four dinosaur genera, ''Chaoyangsaurus'', ''Xuanhuaceratops'', ''Yinlong'' and ''Hualianceratops'', are usually considered to belong to the Chaoyangsauridae. In 2020, Yu ''et al''. classified ''Stenopelix'' as a chaoyangsaurid.
All five animals are more primitive (or basal) than both ''Psittacosaurus'' and neoceratopsians.
See also
* Timeline of ceratopsian research
References
Chaoyangsauridae,
Dinosaur families
Late Jurassic dinosaurs
Dinosaurs of China
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