Qianxisaurus is known solely from the holotype NMNS-KIKO-F044630, a nearly complete and articulated skeleton missing only the tip of the tail and the right hindlimb, housed at the National Museum of Natural Science in Taichung, Taiwan. The holotype is exposed mostly in a view from above, with the tail gradually turning to left side view. The skull measures at 7.6 cm (3.0 in) in length, and the total length of the individual is estimated to have been over 80 cm (2 ft 7 in). Only the first 31 tail vertebrae are preserved, out of at least 42-48 vertebrae that are expected to comprise the tail based on other closely related pachypleurosaurs, which implies a total body length longer than 80 cm for this individual. NMNS-KIKO-F044630 was discovered in 2006 near the Huangnihe River at Chajiang of Xingyi, southwesternmost Guizhou Province. It was most probably collected from the Zhuganpo Member of the Falang Formation based on field expeditions to the area in 2006, somewhere between the Geju railway station and Chajiang railway station along the east side of the river which is the provincial boundary between Guizhou and Yunnan, thus dating to the Ladinian stage of the late Middle Triassic, about 238 million years ago.[1]
Etymologyedit
Qianxisaurus was first described and named by Yen-Nien Cheng, Xiao-Chun Wu, Tamaki Sato and Hsi-Yin Shan in 2012 and the type species is Qianxisaurus chajiangensis. The generic name is derived from Qianxi, which refers to the western part of Guizhou Province where the holotype was found, a spelling based on the Chinese Pinyin, and from Greeksaurus, meaning "lizard", a common suffix for genus names of extinct reptiles. The specific name is derived from Chajiang, a town near which the specimen was collected, with the edition of the Latin suffix -ensis, meaning "from".[1]
Descriptionedit
Qianxisaurus is a basaleosauropterygian, potentially related to Nothosauroidea, with an estimated total body length of at least 80 cm (2 ft 7 in). Originally considered to be a juvenile of the nothosauridLariosaurus due to the presence of four sacral vertebrae, further preparation revealed its unique skull roof and dentitionmorphology. Qianxisaurus bears a premaxilla with eight teeth, contributing a small portion to the elongated oval external naris, teeth with a slightly constricted peduncle and a short conical crown, and a very small supratemporal fenestra, only slightly larger than the foramen of the parietal bone. These autapomorphic traits are unique to Qianxisaurus among all known eosauropterygians. Other unusual traits include a snout longer than the rest of skull, an irregular shape of postorbital bone with a truncated projection of the top surface and a forked projection of the back surface, short and stout retroarticular process that is not concave but truncated in its back portion, a relatively long body with 28 back vertebrae, the presence of four sacral vertebrae, ribs which are not pachyostotic, and a coracoid with a narrow, column-shaped side portion and a widened, foot-shaped mid portion. Qianxisaurus shares the presence of a longitudinal groove on upper-back-facing surface of dorsal ribs exclusively with the potential basal pistosauroidsCorosaurus, Sanchiaosaurus, Kwangsisaurus and Chinchenia.[1]
Referencesedit
^ abcdCheng, Y. N.; Wu, X. C.; Sato, T.; Shan, H. Y. (2012). "A new eosauropterygian (Diapsida, Sauropterygia) from the Triassic of China". Journal of Vertebrate Paleontology. 32 (6): 1335. doi:10.1080/02724634.2012.695983. S2CID 85253142.
qianxisaurus, extinct, genus, pachypleurosaur, alternatively, basal, eosauropterygian, known, from, middle, triassic, ladinian, guizhou, province, southwestern, china, contains, single, species, chajiangensis, temporal, range, ladinian, preꞒ, scientific, class. Qianxisaurus is an extinct genus of pachypleurosaur or alternatively a basal eosauropterygian known from the Middle Triassic Ladinian age of Guizhou Province southwestern China It contains a single species Qianxisaurus chajiangensis 1 QianxisaurusTemporal range Ladinian 242 237 Ma PreꞒ Ꞓ O S D C P T J K Pg N Scientific classificationDomain EukaryotaKingdom AnimaliaPhylum ChordataClass ReptiliaSuperorder SauropterygiaClade EosauropterygiaGenus QianxisaurusCheng et al 2012Type species Qianxisaurus chajiangensisCheng et al 2012 Contents 1 Discovery 2 Etymology 3 Description 4 ReferencesDiscovery editQianxisaurus is known solely from the holotype NMNS KIKO F044630 a nearly complete and articulated skeleton missing only the tip of the tail and the right hindlimb housed at the National Museum of Natural Science in Taichung Taiwan The holotype is exposed mostly in a view from above with the tail gradually turning to left side view The skull measures at 7 6 cm 3 0 in in length and the total length of the individual is estimated to have been over 80 cm 2 ft 7 in Only the first 31 tail vertebrae are preserved out of at least 42 48 vertebrae that are expected to comprise the tail based on other closely related pachypleurosaurs which implies a total body length longer than 80 cm for this individual NMNS KIKO F044630 was discovered in 2006 near the Huangnihe River at Chajiang of Xingyi southwesternmost Guizhou Province It was most probably collected from the Zhuganpo Member of the Falang Formation based on field expeditions to the area in 2006 somewhere between the Geju railway station and Chajiang railway station along the east side of the river which is the provincial boundary between Guizhou and Yunnan thus dating to the Ladinian stage of the late Middle Triassic about 238 million years ago 1 Etymology editQianxisaurus was first described and named by Yen Nien Cheng Xiao Chun Wu Tamaki Sato and Hsi Yin Shan in 2012 and the type species is Qianxisaurus chajiangensis The generic name is derived from Qianxi which refers to the western part of Guizhou Province where the holotype was found a spelling based on the Chinese Pinyin and from Greek saurus meaning lizard a common suffix for genus names of extinct reptiles The specific name is derived from Chajiang a town near which the specimen was collected with the edition of the Latin suffix ensis meaning from 1 Description editQianxisaurus is a basal eosauropterygian potentially related to Nothosauroidea with an estimated total body length of at least 80 cm 2 ft 7 in Originally considered to be a juvenile of the nothosaurid Lariosaurus due to the presence of four sacral vertebrae further preparation revealed its unique skull roof and dentition morphology Qianxisaurus bears a premaxilla with eight teeth contributing a small portion to the elongated oval external naris teeth with a slightly constricted peduncle and a short conical crown and a very small supratemporal fenestra only slightly larger than the foramen of the parietal bone These autapomorphic traits are unique to Qianxisaurus among all known eosauropterygians Other unusual traits include a snout longer than the rest of skull an irregular shape of postorbital bone with a truncated projection of the top surface and a forked projection of the back surface short and stout retroarticular process that is not concave but truncated in its back portion a relatively long body with 28 back vertebrae the presence of four sacral vertebrae ribs which are not pachyostotic and a coracoid with a narrow column shaped side portion and a widened foot shaped mid portion Qianxisaurus shares the presence of a longitudinal groove on upper back facing surface of dorsal ribs exclusively with the potential basal pistosauroids Corosaurus Sanchiaosaurus Kwangsisaurus and Chinchenia 1 References edit a b c d Cheng Y N Wu X C Sato T Shan H Y 2012 A new eosauropterygian Diapsida Sauropterygia from the Triassic of China Journal of Vertebrate Paleontology 32 6 1335 doi 10 1080 02724634 2012 695983 S2CID 85253142 nbsp Paleontology portal Retrieved from https en wikipedia org w index php title Qianxisaurus amp oldid 1137627585, wikipedia, wiki, book, books, library,
