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

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of herbivorous

hadrosauroid Hadrosauroidea is a clade or superfamily of ornithischian dinosaurs that includes the "duck-billed" dinosaurs, or hadrosaurids, and all dinosaurs more closely related to them than to ''Iguanodon''. Their remains have been recovered in Asia, Eu ...

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 ...

from the Early Cretaceous (

Albian The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/ Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0 ...

stage Stage or stages may refer to: Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly British theatre newspaper * Sta ...

) 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 (, ; alternately romanized as Kansu) is a province in Northwest China. Its capital and largest city is Lanzhou, in the southeast part of the province. The seventh-largest administrative district by area at , Gansu lies between the Tibeta ...

.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 branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

''equus'', "horse", and ''juba'', "mane". The specific epithet "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. ** Britishness, the British identity and common culture * British English, ...

palaeontologist 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 fossi ...

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

''Equijubus normani'' was formally named in an article by You, Luo Zhexi,

Neil Shubin Neil Shubin (born December 22, 1960) is an American paleontologist, evolutionary biologist and popular science writer. He is the Robert R. Bensley Professor of Organismal Biology and Anatomy, Associate Dean of Organismal Biology and Anatomy and ...

, Lawrence Witmer,

Tang Zhilu Tang or TANG most often refers to: * Tang dynasty * Tang (drink mix) Tang or TANG may also refer to: Chinese states and dynasties * Jin (Chinese state) (11th century – 376 BC), a state during the Spring and Autumn period, called Tang (唐) b ...

and Tang Feng in 2003. The type specimen or

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

, IVPP V12534, consists of a complete skull with articulated (attached) lower jaws, plus associated incomplete

postcrania Postcrania (postcranium, adjective: postcranial) in zoology and vertebrate paleontology is all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g. of dinosaurs or other extinct tetrapods, consist of partial or isolated sk ...

: nine

cervical In anatomy, cervical is an adjective that has two meanings: # of or pertaining to any neck. # of or pertaining to the female cervix: i.e., the ''neck'' of the uterus. *Commonly used medical phrases involving the neck are **cervical collar **cerv ...

(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 * Dorsal c ...

(back), and six

sacral Sacral may refer to: *Sacred Sacred describes something that is dedicated or set apart for the service or worship of a deity; is considered worthy of spiritual respect or devotion; or inspires awe or reverence among believers. The property ...

(pelvic)

vertebrae The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristi ...

. It was found in fluvio-

lacustrine A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...

sediments of the Middle Grey Unit of the Xinminpu Group, Gonpoquan Basin, Mazong Shan,

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

grass Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns a ...

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 Grazer may refer to: *grazer, an animal that grazes *Grazer, a native or inhabitant of Graz *GRAZER, the shoegaze band GRAZER Astronomy * Earth Grazer, Earth-grazing fireball that enters the Earth's atmosphere and leaves again * Mercury 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, and more recently has examined sociology and theology. He is best known for his work and research on theropod dino ...

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. The human eye ...

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 Iguanodontia (the iguanodonts) is a clade of herbivorous dinosaurs that lived from the Middle Jurassic to Late Cretaceous. Some members include ''Camptosaurus'', ''Dryosaurus'', ''Iguanodon'', '' Tenontosaurus'', and the hadrosaurids or "duck-bil ...

. The discoverers considered it to be the basal-most of the hadrosauroids, and suggested that this group emerged in

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

References

External links

* https://web.archive.org/web/20050305220103/http://www.sinofossa.org/sinosaur/equijubus.htm {{Taxonbar, from=Q941092 Iguanodonts Early Cretaceous dinosaurs of Asia Hadrosaurs Fossil taxa described in 2003 Taxa named by Neil Shubin Paleontology in Gansu Ornithischian genera

Discovery and naming

Description

Phylogeny

See also

References

External links