''Equijubus'' (; ''Mǎzōng'' meaning "horse mane" after the area Mǎzōng Mountain 马鬃山 in which it was found), is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of herbivorous hadrosauroid

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 ...

from the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

(

Albian The Albian is both an age (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...

stage) of northwestern China.

Discovery and naming

The type (and only known) specimen was found in the summer of 2000 by a Chinese-American expedition in the Mazong (= "horse mane") Shan area of China's

Gansu Province Gansu is a provinces of China, province in Northwestern China. Its capital and largest city is Lanzhou, in the southeastern part of the province. The seventh-largest administrative district by area at , Gansu lies between the Tibetan Plateau, Ti ...

.You, Luo, Shubin, Witmer, Tang and Tang (2003). "The earliest-known duck-billed dinosaur from deposits of late Early Cretaceous age in northwest China and hadrosaurid evolution." ''Cretaceous Research'', 24: 347-353. In 2002 You Hialu in a dissertation named and described the species ''Equijubus normani''. The generic name is derived from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''equus'', "horse", and ''juba'', "mane". The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

"normani" is in honour of

British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories and Crown Dependencies. * British national identity, the characteristics of British people and culture ...

palaeontologist Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...

David B. Norman. However, such a ''nomen ex dissertatione'' does not constitute a valid name. The

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

''Equijubus normani'' was formally named in an article by You, Luo Zhexi, Neil Shubin, Lawrence Witmer, Tang Zhilu and Tang Feng in 2003. The type specimen or

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

, IVPP V12534, consists of a complete skull with articulated (attached) lower jaws, plus associated incomplete postcrania: nine cervical (neck), sixteen

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...

(back), and six sacral (pelvic)

vertebrae Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

. It was found in fluvio- lacustrine sediments of the Middle Grey Unit of the Xinminpu Group, Gonpoquan Basin, Mazong Shan,

, China. Wu, You & Li (2018) described

grass Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family (biology), family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and spe ...

microfossils extracted from a specimen of ''Equijubus normani'', which at the time of their description were the oldest known grass fossils, and might be the oldest known evidence of a dinosaur feeding on grasses, implying that it was most likely a grazer.

Description

''Equijubus'' is a relatively large euornithopod.

Gregory S. Paul Gregory Scott Paul (born December 24, 1954) is an American freelance researcher, author and illustrator who works in paleontology. He is best known for his work and research on theropoda, theropod dinosaurs and his detailed illustrations, both l ...

in 2010 estimated the length at seven metres, the weight at 2.5 tonnes.Paul, G.S., 2010, ''The Princeton Field Guide to Dinosaurs'', Princeton University Press p. 292 A

palpebral An eyelid ( ) is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily. "Palpebral" ...

bone seems to be absent, meaning the eyes were not overshadowed by an upper rim as with most related species.

Phylogeny

''Equijubus'' was described as a basal hadrosauroid dinosaur, although it may turn out to be a non-hadrosauroid iguanodont. The discoverers considered it to be the basal-most of the hadrosauroids, and suggested that this group emerged in

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

References

External links

* https://web.archive.org/web/20050305220103/http://www.sinofossa.org/sinosaur/equijubus.htm {{Taxonbar, from=Q941092 Hadrosauroidea Dinosaur genera Albian dinosaurs Fossil taxa described in 2003 Taxa named by Neil Shubin Taxa named by Hailu You Dinosaurs of China

Discovery and naming

Description

Phylogeny

See also

References

External links