''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 ...

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 of southern China. It was similar to '' Heyuannia'', 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 Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

''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 in

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 ...

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 seve ...

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" ...

, 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. In contrast to its nearest relatives, ''Jiangxisaurus'' has an elongated mandible and a less pronounced down-turned rostrum 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 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 The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...

length of about 70%

Paleoecology

Provenance and occurrence

The only known specimen of this genus was recovered at the Nankang locality of the Nanxiong Formation in Ganzhou City of

Jiangxi Province Jiangxi (; ; formerly romanized as Kiangsi or Chianghsi) is a landlocked province in the east of the People's Republic of China. Its major cities include Nanchang and Jiujiang. Spanning from the banks of the Yangtze river in the north into hi ...

, 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 interv ...

stage 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 Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their ...

Gannansaurus ''Gannansaurus'' (meaning " Gannan lizard") is an extinct genus of somphospondylan sauropod dinosaur known from the late Late Cretaceous Nanxiong Formation of Ganzhou Basin, Jiangxi Province of southern China. It is known from specimen GMNH F10 ...

'', the duckbill '' Microhadrosaurus'', the therizinosauroid '' Nanshiungosaurus'', the tyrannosaurid '' Qianzhousaurus'' and other oviraptorids, '' Banji'', ‘’ Tongtianlong’’, ‘’

Shixinggia ''Shixinggia'' is a genus of oviraptorosaurian dinosaur from the Late Cretaceous period of Shixing County, Guangdong, China, for which it was named. While no skull was recovered, the specimen (BVP-112) is known from a fair amount of post-cranial ...

’’,‘’ 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 ''Huanansaurus'' is an extinct genus of oviraptorid dinosaur that lived approximately 72 million years ago, between the Campanian and Maastrichtian, during the latter part of the Cretaceous period in what is now China, in the Nanxiong Formation. ...

’’ 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