''Gongxianosaurus'' is a genus of basal

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 bo ...

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

Jurassic Period The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

(

Toarcian The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic. It spans the time between 182.7 Ma (million years ago) and 174.1 Ma. It follows the Pliensbachian and is followed by the Aalenian. The Toarcian ...

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 ...

). The only species is ''Gongxianosaurus shibeiensis''. Based on four fragmentary to complete specimens found in

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

(

Sichuan Province Sichuan (; zh, c=, labels=no, ; zh, p=Sìchuān; alternatively romanized as Szechuan or Szechwan; formerly also referred to as "West China" or "Western China" by Protestant missions) is a province in Southwest China occupying most of the ...

), it is one of the most completely known early sauropods. The skeleton is known in large part, missing both the hand and the majority of the skull. ''Gongxianosaurus'' was firstly named and described in a short note published in 1998; however, a comprehensive description has yet to be published. ''Gongxianosaurus shibeiensis'' was named for the place it was found, near the village Shibei in Gong County (珙县;

Pinyin Hanyu Pinyin (), often shortened to just pinyin, is the official romanization system for Standard Mandarin Chinese in China, and to some extent, in Singapore and Malaysia. It is often used to teach Mandarin, normally written in Chinese for ...

: Gǒng Xiàn).

Description

''Gongxianosaurus'' may have reached in length. Like other sauropods, it moved

quadruped Quadrupedalism is a form of locomotion where four limbs are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four limbs is said to be a quadruped (from Latin ''quattuor' ...

ally (on four legs), as indicated by the elongated fore limbs that reached 70 to 75% of hind limb length. The pedal phalanges were short and robust, as typical for sauropods. The pedal

phalangeal formula The phalanges (singular: ''phalanx'' ) are digital bones in the hands and feet of most vertebrates. In primates, the thumbs and big toes have two phalanges while the other digits have three phalanges. The phalanges are classed as long bones. ...

, counting the number of phalanges for each digit starting from the innermost, was 2-3-4-5-1. All but the outermost digit ended in claws. Unlike in other sauropods,

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 ...

(deep lateral excavations of the vertebrae) were absent; thus, the vertebrae would have been quite massive. The

sacrum The sacrum (plural: ''sacra'' or ''sacrums''), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30. The sacrum situates at the upper, back part ...

was made of three fused sacral vertebrae, fewer than in later sauropods. The

chevrons Chevron (often relating to V-shaped patterns) may refer to: Science and technology * Chevron (aerospace), sawtooth patterns on some jet engines * Chevron (anatomy), a bone * '' Eulithis testata'', a moth * Chevron (geology), a fold in rock l ...

were unbifurcated. An important characteristic of sauropod limbs is their reduced

ossification Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in t ...

– the tendency to replace bone by

cartilage Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck an ...

. ''Gongxianosaurus'' is the only known sauropod with ossified distal tarsals. Thus, either ''Gongxianosaurus'' was one of the basalmost sauropods, or ossified distal tarsals were present in other early sauropods but are simply not preserved due to the fragmentation of the specimens.

Classification

Because the fossils are not fully described yet, available character information that can be used in cladistic analyses is limited. Thus, only few cladistical analyses have incorporated ''Gongxianosaurus''. A recent analysis by Apaldetti et al. (2011) suggests that ''Gongxianosaurus'' was more basal than ''

Vulcanodon ''Vulcanodon'' (meaning "volcano tooth") is an extinct genus of sauropod dinosaur from the Early Jurassic of southern Africa. The only known species is ''V. karibaensis''. Discovered in 1969 in Zimbabwe, it was regarded as the earliest-known sau ...

'', ''

Tazoudasaurus ''Tazoudasaurus'' is a genus of vulcanodontid sauropod dinosaurs hailing from the Early Jurassic, located in the High Atlas Mountains of Morocco in North Africa. Along with ''Ohmdenosaurus'' is one of the two formally described sauropods from th ...

'' and ''

Isanosaurus ''Isanosaurus'' means "North-eastern thailand lizard" was a sauropod dinosaur from Thailand. It was originally dated to approximately 210 million years ago during the Late Triassic (late Norian to Rhaetian stages), which would make it on ...

'', but more derived than the early sauropods ''

Antetonitrus ''Antetonitrus'' is a genus of sauropod dinosaur found in the Early Jurassic Elliot Formation of South Africa. The only species is ''Antetonitrus ingenipes''. As one of the oldest known sauropods, it is crucial for the understanding of the origi ...

'', ''

Lessemsaurus ''Lessemsaurus'' is an extinct genus of sauropod dinosaur belonging to Lessemsauridae. Naming and description The type species, ''L. sauropoides'', was formally described by José Fernando Bonaparte in 1999 in honor of Don Lessem, a writer of ...

'', ''

Blikanasaurus ''Blikanasaurus'' is a genus of sauropodomorph dinosaur from the late Triassic of South Africa. The generic name ''Blikanasaurus'' is derived from Greek, meaning "lizard from Blikana". The species name ''cromptoni'' is taken from the surname of ...

'', '' Camelotia'' and '' Melanorosaurus''.

Discovery

''Gongxianosaurus'' fossils were found near the village of Shibei (Sichuan province) in purple

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...

s pertaining to the

Ziliujing Formation The Ziliujing Formation is a geological formation in China, It is Early Jurassic in age. It is part of the stratigraphy of the Sichuan Basin. The dinosaur ''Gongxianosaurus'' and indeterminate theropod material are known from the Dongyuemiao Mem ...

(Dongyueshan Member). These rocks are considered to be

in age (182.7 to 174.1 mya). Thus, ''Gongxianosaurus'' is geologically younger than the "

prosauropod Sauropodomorpha ( ; from Greek, meaning "lizard-footed forms") is an extinct clade of long-necked, herbivorous, saurischian dinosaurs that includes the sauropods and their ancestral relatives. Sauropods generally grew to very large sizes, had lon ...

" ''

Lufengosaurus ''Lufengosaurus'' (, meaning "Lufeng lizard") is a genus of Massospondylidae, massospondylid dinosaur which lived during the Early Jurassic period in what is now southwestern China. Discovery, taxonomy and research During the late 1930s geologi ...

'' but older than the basal sauropod ''

Shunosaurus ''Shunosaurus'', meaning "shu lizard", is a genus of sauropod dinosaur from Late Jurassic ( Oxfordian) beds in Sichuan Province in China, approximately 159±2 million years ago. The name derives from "Shu", an ancient name for the Sichuan p ...

''. The fossils were found in May 1997 during a geological exploration. Excavation started in the same month and led to the recovery of a wealth of fossils in an area of approximately 200 square meters. While most fossils pertain to a new sauropod genus, remains of

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 ...

s have also been found. The sauropod material includes four fragmentary to complete individuals similar in size, together encompassing most of the skeleton, though hand and skull bones were not found except a

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has b ...

and teeth. In 1998, the sauropod material was briefly described as a new genus and species, ''Gongxianosaurus shibeiensis'', in a preliminary note by palaeontologists led by He Xinlu. A more detailed description was announced, noting that excavation was still in progress while the paper was published. In 2000, a second short description was published by Luo Yaonan and Wang Changsheng, also presenting ''Gongxianosaurus'' as a new sauropod and without mentioning the first description that was published two years before. Also, much of the information published by Luo and Wang was already published by He and colleagues. Luo and Wang suggest that several bones may not pertain to 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 specimen ...

''Gongxianosaurus shibeiensis'' but to a second species of ''Gongxianosaurus''. Those remains were informally placed within the separate genus and species " Yibinosaurus zhoui" in 2001 and 2003 respectively by

Ouyang Hui Ouyang () is a Chinese surname. It is the most common two-character Chinese compound surname, being the only two-character name of the 400 most common Chinese surnames, according to a 2013 study, and is one of the few two-character surnames that h ...

.Ouyang, 2003. ''Skeletal characteristics of '' Mamenchisaurus youngi'' and the systematics of

mamenchisaurids Mamenchisauridae is a family of sauropod dinosaurs belonging to Eusauropoda known from the Jurassic and Early Cretaceous of Asia and Africa. Some members of the group reached gigantic sizes, amongst the largest of all sauropods. Classification T ...

.'' PhD thesis. Chengdu University of Technology. 176 pp.

References

{{Taxonbar, from=Q1710249 Sauropods Early Jurassic dinosaurs of Asia Paleontology in Sichuan Fossil taxa described in 1998