''Liaoceratops'', meaning "Liaoning horned face", is a

ceratopsian 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, Europe, and Asia, during the Cretaceous Period (geology), Period, although anc ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

believed to be an early relative of the horned

ceratopsid Ceratopsidae (sometimes spelled Ceratopidae) is a family of ceratopsian dinosaurs including ''Triceratops'', ''Centrosaurus'', and ''Styracosaurus''. All known species were quadrupedal herbivores from the Upper Cretaceous. All but one species are ...

s. It lived in the Early

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

, 126 million years ago. It was discovered in

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...

by a team of American and Chinese scientists. ''Liaoceratops'' was much smaller than its later relatives, but offers a glimpse into the early

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

of this group of dinosaurs. Liaoceratops BW

Discoveries and naming

''Liaoceratops'' was discovered in the famous

Liaoning Liaoning () is a coastal province in Northeast China that is the smallest, southernmost, and most populous province in the region. With its capital at Shenyang, it is located on the northern shore of the Yellow Sea, and is the northernmo ...

Province of China, where several

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

of feathered dinosaurs have also been collected. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specim ...

''Liaoceratops yanzigouensis'' was in 2002 named and described by Xu Xing, Peter Makovicky,

Wang Xiaolin Wang may refer to: Names * Wang (surname) (王), a common Chinese surname * Wāng (汪), a less common Chinese surname * Titles in Chinese nobility * A title in Korean nobility * A title in Mongolian nobility Places * Wang River in Thailand ...

, Mark Norell and

You Hailu In Modern English, ''you'' is the second-person pronoun. It is grammatically plural, and was historically used only for the dative case, but in most modern dialects is used for all cases and numbers. History ''You'' comes from the Proto- ...

. The generic name is derived from

and the Greek ''keras'', "horn" and ''ops'', "face". The specific name refers to the town Yanzigou. The holotype IVPP V12738 has been found in the

Yixian Formation The Yixian Formation (; formerly transcribed as Yihsien Formation) is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans the late Barremian and early Aptian stages of the Early Cretaceous. It is known for its exq ...

dating from the

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is preceded ...

. These beds have also yielded fossil

insects Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of j ...

, fossils of

ginkgo ''Ginkgo'' is a genus of non-flowering seed plants. The scientific name is also used as the English name. The order to which it belongs, Ginkgoales, first appeared in the Permian, 270 million years ago, and is now the only living genus with ...

trees, and many other dinosaurs, including the early

troodontid Troodontidae is a clade of bird-like theropod dinosaurs. During most of the 20th century, troodontid fossils were few and incomplete and they have therefore been allied, at various times, with many dinosaurian lineages. More recent fossil disco ...

Sinovenator ''Sinovenator'' (meaning "Chinese hunter") is a genus of troodontid dinosaur from China. It is from the early Cretaceous Period. Discovery and naming Two specimens of a troodontid were described in 2002. They are both housed in the Institu ...

'', also described by Makovicky later in 2002. "This area is yielding extremely important information on the evolution of dinosaurs,

mammals Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur o ...

, insects, and flowering

plants Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclude ...

. I hope to find even more primitive specimens than ''Liaoceratops''," Peter Makovicky said. The holotype consists of an almost complete skull. As

paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). O ...

specimen IVPP V12633 has been referred, the skull of a juvenile. In 2007 another skull, CAGS-IG-VD-002, of an even younger individual was referred. This lacked the skull roof, which has been explained as the result of a predator opening the braincase to eat the contents.You, H., Tanoue, K., and Dodson, P., 2007, "A new specimen of ''Liaoceratops yanzigouensis'' (Dinosauria: Neoceratopsia) from the Early Cretaceous of Liaoning Province, China", ''Acta Geologica Sinica'' 81(6): 898-904

Description and classification

''Liaoceratops'' was a relatively small dinosaur, reaching in length and in body mass. The holotype skull measures of 154 millimetres in length, weighing an estimated seven pounds and possessing only jugal horns and a small skull frill, lacking the orbital horns and true neck shield that characterized later ceratopsians. However, these features help understand a major split in the evolution of ceratopsians. Long before the familiar ''

Triceratops ''Triceratops'' ( ; ) is a genus of herbivorous chasmosaurine ceratopsid dinosaur that first appeared during the late Maastrichtian stage of the Late Cretaceous period, about 68 million years ago in what is now North America. It is one ...

'' evolved in

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

, the ceratopsian lineage branched into two lines: the

neoceratopsians Ceratopsia or Ceratopia ( or ; Greek: "horned faces") is a group of herbivorous, beaked dinosaurs that thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic. ...

, the main lineage that includes the recognizable horned and frilled forms, and of which ''Liaoceratops'' in 2002 was the most basal known member, and the Psittacosauridae, a radiation of smaller, parrot-beaked dinosaurs. "''Liaoceratops'' gives us a great window on the early evolution of horned dinosaurs and tells us that ''Triceratops'' and its relatives evolved from very small Asian ceratopsians. This small, primitive dinosaur is actually more interesting to

science Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence ...

in many ways than its larger, more famous relatives because it teaches us more about evolution. Basal dinosaurs are critical because they help us to tie different groups of dinosaurs together and map out evolutionary patterns," said Peter Makovicky, Curator of Dinosaurs at the

Field Museum The Field Museum of Natural History (FMNH), also known as The Field Museum, is a natural history museum in Chicago, Illinois, and is one of the largest such museums in the world. The museum is popular for the size and quality of its educational ...

Chicago (''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = List of sovereign states, Count ...

and a co-author of the paper describing the dinosaur. "''Liaoceratops'' establishes that this split occurred no later than the earliest part of the

Period. Also, it indicates that ceratopsians acquired some of their distinctive features earlier and more rapidly than was previously recognized," Makovicky said.

Function of the horns and frill

Ironically, the diminutive ''Liaoceratops'' may also help scientists understand the roles of horns and frills in ceratopsian dinosaurs. First thought of as offensive or defensive organs, these structures are seen by many

paleontologists Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of foss ...

today as display devices used in species recognition and to attract mates. ''Liaoceratops'' has a small jugal horn facing sideways under and behind each of its eyes. As this structure is relatively small and light, Makovicky believed that it was a display organ and had no purpose in defense.

Notes

External links

''Liaoceratops'' in the Dino Directory
{{Taxonbar, from=Q133133 Early Cretaceous dinosaurs of Asia Neoceratopsians Yixian fauna Taxa named by Xu Xing Taxa named by Mark Norell Fossil taxa described in 2002 Ornithischian genera

Discoveries and naming

Description and classification

Function of the horns and frill

See also

Notes

External links