''Jiangxisaurus'' is an extinct genus of

oviraptorid Oviraptoridae is a group of bird-like, herbivorous and omnivorous maniraptoran dinosaurs. Oviraptorids are characterized by their toothless, parrot-like beaks and, in some cases, elaborate crests. They were generally small, measuring between on ...

theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...

dinosaur from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

Nanxiong Formation The Nanxiong Formation (also known as Yuanpu Formation) is a Late Cretaceous geologic formation in Guangdong Province. Dinosaur remains are among the fossils that have been recovered from the formation. Description It consists of continental s ...

of southern China. It was similar to ''

Heyuannia ''Heyuannia'' ("from Heyuan") is a genus of oviraptorid dinosaur that lived in Asia during the Late Cretaceous epoch, in what is now China and Mongolia. It was the first oviraptorid found in China; most others were found in neighbouring Mongoli ...

'', but with more strongly curved anterior claws and a thinner, frailer mandible. This find is paleontologically significant because it contributes to current knowledge about the paleogeographical distribution of oviraptorids in southern China. It was most likely a herbivorous animal along with its close relatives '' Nankangia'' and '' Ganzhousaurus''.

Etymology

The genus name ''Jiangxisaurus'', refers to the Jiangxi Province of southern China. The specific name ''ganzhouensis'', is derived from Ganzhou, the locality where the specimen was discovered. ''Jiangxisaurus'' was described and named by Wei Xuefang, Pu Hanyong, Xu Li, Liu Di, and

Lü Junchang Lü Junchang (; 1965 – 9 October 2018) was a Chinese palaeontologist and professor at the Institute of Geology, Chinese Academy of Geological Sciences. An expert on Mesozoic reptiles, he described and named dozens of dinosaur and pterosaur taxa ...

2013 File:2013 Events Collage V2.png, From left, clockwise: Edward Snowden becomes internationally famous for leaking classified NSA wiretapping information; Typhoon Haiyan kills over 6,000 in the Philippines and Southeast Asia; The Dhaka garment fa ...

and the type species is ''Jiangxisaurus ganzhouensis''.

Description

The

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 ...

specimen HGM41-HIII0421 consists of an incomplete skull, a lower jaw, eight cervical vertebrae, three dorsal vertebrae, nine caudal vertebrae, a nearly complete pectoral girdle, two chevrons, the left forelimb, both sternal plates, four sternal ribs, nine dorsal ribs, and a partially preserved pelvic girdle. The skull is 150mm long and appears to be a sub-adult. The mandible of ''Jiangxisaurus'' is toothless and has a height-to-length ratio of about 20%. The radius is 96mm in length and is 30% shorter than the length of the humerus (136mm). The manus is

tridactyl In biology, dactyly is the arrangement of digits (fingers and toes) on the hands, feet, or sometimes wings of a tetrapod animal. It comes from the Greek word δακτυλος (''dáktylos'') = "finger". Sometimes the ending "-dactylia" is use ...

, meaning that it has three fingers – the first digit is robust, the second is elongated and the third digit is slender.

Classification

''Jiangxisaurus'' was assigned to the taxon

oviraptoridae Oviraptoridae is a group of bird-like, herbivorous and omnivorous maniraptoran dinosaurs. Oviraptorids are characterized by their toothless, parrot-like beaks and, in some cases, elaborate crests. They were generally small, measuring between on ...

. This genus shares several traits with other oviraptorids, including a short narrow skull with a toothless jaw, and anterior cerivcal vertebrae that bear

pleurocoels Skeletal pneumaticity is the presence of air spaces within bones. It is generally produced during development by excavation of bone by pneumatic diverticula (air sacs) from an air-filled space, such as the lungs or nasal cavity. Pneumatization is h ...

. In contrast to its nearest relatives, ''Jiangxisaurus'' has an elongated mandible and a less pronounced down-turned

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ships * Ros ...

on its lower jaw.

Distinguishing anatomical features

A diagnosis is a statement of the anatomical features of an organism (or group) that collectively distinguish it from all other organisms. Some, but not all, of the features in a diagnosis are also autapomorphies. An autapomorphy is a distinctive anatomical feature that is unique to a given organism. According to Wei et al. (2013), ''Jiangxisaurus'' was a medium-sized oviraptorid dinosaur characterized by the following unique characters: * the presence of a weakly down-turned mandibular symphysis * a

suprangular The suprangular or surangular is a jaw bone found in most land vertebrates, except mammals. Usually in the back of the jaw, on the upper edge, it is connected to all other jaw bones: dentary, angular, splenial and articular The articular bone ...

bone with an elongated and concave lateral surface * a very elongated mandible, with a height-to-length ratio of about 20% * a ratio of

radius In classical geometry, a radius ( : radii) of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', meaning ray but also the ...

length to humerus length of about 70%

Paleoecology

Provenance and occurrence

The only known specimen of this genus was recovered at the Nankang locality of the

in Ganzhou City of Jiangxi Province, China. The specimen was collected in red sandstone sediments that were deposited during the

Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval ...

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 the

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 ...

period, approximately 72 to 66 million years ago. The type specimen is currently housed at the Henan Geological Museum (HGM).

Fauna and habitat

The Nanxiong Formation consists of a 2000-meter sequence of red sandstones and clays which has yielded dinosaur fossils, dinosaur footprints and abundant egg shells. ''Jiangxisaurus'' shared its paleoenvironment with the sauropod '' Gannansaurus'', the duckbill ''

Microhadrosaurus ''Microhadrosaurus'' (meaning "small sturdy lizard" in Greek) is a genus of hadrosaurid dinosaur from the Campanian or Maastrichtian-age Upper Cretaceous Yuanpu Formation (also known as the Nanxiong Formation) of Guangdong, China. Although its n ...

'', the

therizinosauroid Therizinosaurs (once called segnosaurs) were large herbivorous theropod dinosaurs whose fossils have been found across the Early to Late Cretaceous deposits in Asia and North America. Various features of the forelimbs, skull and pelvis unite t ...

Nanshiungosaurus ''Nanshiungosaurus'' (meaning "Nanxiong's lizard") is a genus of therizinosaurid that lived in what is now Asia during the Late Cretaceous of South China. The type species, ''Nanshiungosaurus brevispinus'', was first discovered in 1974 and desc ...

'', the

tyrannosaurid Tyrannosauridae (or tyrannosaurids, meaning "tyrant lizards") is a family of coelurosaurian theropod dinosaurs that comprises two subfamilies containing up to thirteen genera, including the eponymous ''Tyrannosaurus''. The exact number of genera ...

'' Qianzhousaurus'' and other oviraptorids, ''

Banji ''Banji'' is an extinct genus of oviraptorid dinosaur that lived approximately 66 million years ago during the later part of the Cretaceous Period in what is now China. It was a small, lightly-built, ground-dwelling, bipedal carnivore, that w ...

'', ‘’

Tongtianlong ''Tongtianlong'' (meaning "Tongtianyan dragon") is a genus of oviraptorid theropod dinosaurs that lived in the late Maastrichtian epoch of the late Cretaceous period. It contains one species, ''T. limosus''. Description ''Tongtianlong'' was a ...

’’, ‘’ Shixinggia’’,‘’ Nankangia’’,‘’

Corythoraptor ''Corythoraptor'' () is a genus of oviraptorid dinosaur from the late Maastrichtian Nanxiong Formation of South China. It contains one species, ''C. jacobsi'', known from a single well-preserved skeleton, and named after paleontologist Louis L ...

’’,’’ Huanansaurus’’ and '' Ganzhousaurus''.

References

{{Taxonbar, from=Q14623729 Late Cretaceous dinosaurs of Asia Fossil taxa described in 2013 Oviraptorids Paleontology in Jiangxi Taxa named by Lü Junchang