[D] Mamenchisaurus anyuensis
Describer
He, Yang, Cai, Li and Liu Z., 1996
Time
Jurassic Late
Classification
Saurischia Sauropodomorpha Sauropoda Euhelopodidae
Diet
Herbivore
Fossilsite
Penglaizhen Formation, Suining Formation, Sichuan Basin, Sichuan, China
Fall Under
Mamenchisaurus
Length
21 meter [or more]
Info
Mamenchisaurus (Young, 1954) > Mamenchisaurus constructus (Young, 1954) > Mamenchisaurus hochuanensis (Young& Chao, 1972) > Mamenchisaurus sinocanadorum (Russell & Zheng, 1994) > Mamenchisaurus youngi (Pi, Ouyang & Ye, 1996) > Mamenchisaurus anyuensis (He, Yang, Cai, Li and Liu Z., 1996) > Mamenchisaurus jingyanensis (Zhang, Li. & Zeng, 1998)
Mamenchisaurus anyuensis sp. nov., was discovered in 1987 in the vicinity of town of Longchiaoxiang, Anyue Co., in the center of the Sichuan Basin. This locality is approximately 180 km southeast of the city of Chengdu and 70 km east northeast of the fossil locality of Dashanpu, Zigong Co. Specimens were excavated from two localities representing stratigraphic horizons in close proximity: the locality of Matisi is 2 km southeast of the administrative office of Longchiaoxiang where the lithology consists of a massive sandstone in the lower section of the Upper Jurassic Penglaizhen Formation.
The second locality, Longjiawa, is approximately 1.7 km east of the administrative office of Longchiaoxiang and east northeast of Matisi where the specimens were collected from a sandstone lens in a predominantly purple-red mudstone unit at the top of the Suining Formation. extremely close to the contact with the overlying Penglaizhen Formation.
Collections from both Longjiawa and Matisi near the town of Longchiaoxiang, Anyue Co., are estimated to include at least ten individuals. With the exception of cranial material, the rest of the skeleton is nearly completely represented. The specimens are considered conspecific due to their distinct consistency in size and morphology.
Type: Specimen AL001 from Matisi is a relatively complete skeleton. With the exception of a small amount of postcranial elements being displaced, the remaining represents the majority of an articulated skeleton with an estimated 8 medial to posterior cervical vertebrae, a complete column of dorsal vertebrae, 5 sacrals, 8 anterior caudals, 15 articulated distal caudals, pectoral and pelvic girdles, nearly complete forelimb, hind limb with damaged tibia and fibula, and lacking a portion of the pes, which is due to taphonomic conditions. Hypodigm: Specimens AL002, AL003, and AL101-106.
M. anyuensis is a large sauropod with a body length of approximately 21 m or more, with typically spoon-shaped, relatively small, teeth. Cervicals exceed 17 in count, there are 12 dorsals, 5 sacrals, and an estimated 50 caudals. Presacral centra are opisthocoelous, centrum walls are extremely thin and interior centrum composition is highly pneumaticized. Cervical pleurocoels are not well developed and centra are relatively elongated, or generally similar to the condition on M. hochuanensis. Posterior cervical and anterior dorsal neural spines are extremely weakly bifid. Dorsals all have typically well develop pleurocoels.
Sacral centra are fused but not conspicuously ventrally constricted and only the first sacral centrum has extremely weak pleurocoels. Anterior caudals are procoelous, neural spines are simple in morphology, and diapophyses are not excessively developed. Medial caudals have bifurcated haemal arches and on the most posterior caudals prezygapophyses and neural spines remain present. The anteroproximal margin of the scapula is appropriately dorsally oblique, there is a conspicuous process on the posterior margin dorsal to the glenoid fossa, the coracoid is semi-elliptical and is in contact with the scapula with a relatively straight suture line.
The clavicle is arched with one end narrow and bifurcated and the other end broad and flat. The humerus is approximately three-quarters the length of the femur and the ulna is two-thirds the length of the humerus. The ilium resembles the basic morphology of Omeisaurus and Mamenchisaurus, the pubic peduncle is robust and situated at the midpoint of the ilium, an ischiac peduncle is indistinct, proximal ischium is distinctly broadened, the shaft is elongated, and the distal end is thin.
Source: Polyglot Paleontologist
He, Yang, Cai, Li and Liu Z., 1996
Time
Jurassic Late
Classification
Saurischia Sauropodomorpha Sauropoda Euhelopodidae
Diet
Herbivore
Fossilsite
Penglaizhen Formation, Suining Formation, Sichuan Basin, Sichuan, China
Fall Under
Mamenchisaurus
Length
21 meter [or more]
Info
Mamenchisaurus (Young, 1954) > Mamenchisaurus constructus (Young, 1954) > Mamenchisaurus hochuanensis (Young& Chao, 1972) > Mamenchisaurus sinocanadorum (Russell & Zheng, 1994) > Mamenchisaurus youngi (Pi, Ouyang & Ye, 1996) > Mamenchisaurus anyuensis (He, Yang, Cai, Li and Liu Z., 1996) > Mamenchisaurus jingyanensis (Zhang, Li. & Zeng, 1998)
Mamenchisaurus anyuensis sp. nov., was discovered in 1987 in the vicinity of town of Longchiaoxiang, Anyue Co., in the center of the Sichuan Basin. This locality is approximately 180 km southeast of the city of Chengdu and 70 km east northeast of the fossil locality of Dashanpu, Zigong Co. Specimens were excavated from two localities representing stratigraphic horizons in close proximity: the locality of Matisi is 2 km southeast of the administrative office of Longchiaoxiang where the lithology consists of a massive sandstone in the lower section of the Upper Jurassic Penglaizhen Formation.
The second locality, Longjiawa, is approximately 1.7 km east of the administrative office of Longchiaoxiang and east northeast of Matisi where the specimens were collected from a sandstone lens in a predominantly purple-red mudstone unit at the top of the Suining Formation. extremely close to the contact with the overlying Penglaizhen Formation.
Collections from both Longjiawa and Matisi near the town of Longchiaoxiang, Anyue Co., are estimated to include at least ten individuals. With the exception of cranial material, the rest of the skeleton is nearly completely represented. The specimens are considered conspecific due to their distinct consistency in size and morphology.
Type: Specimen AL001 from Matisi is a relatively complete skeleton. With the exception of a small amount of postcranial elements being displaced, the remaining represents the majority of an articulated skeleton with an estimated 8 medial to posterior cervical vertebrae, a complete column of dorsal vertebrae, 5 sacrals, 8 anterior caudals, 15 articulated distal caudals, pectoral and pelvic girdles, nearly complete forelimb, hind limb with damaged tibia and fibula, and lacking a portion of the pes, which is due to taphonomic conditions. Hypodigm: Specimens AL002, AL003, and AL101-106.
M. anyuensis is a large sauropod with a body length of approximately 21 m or more, with typically spoon-shaped, relatively small, teeth. Cervicals exceed 17 in count, there are 12 dorsals, 5 sacrals, and an estimated 50 caudals. Presacral centra are opisthocoelous, centrum walls are extremely thin and interior centrum composition is highly pneumaticized. Cervical pleurocoels are not well developed and centra are relatively elongated, or generally similar to the condition on M. hochuanensis. Posterior cervical and anterior dorsal neural spines are extremely weakly bifid. Dorsals all have typically well develop pleurocoels.
Sacral centra are fused but not conspicuously ventrally constricted and only the first sacral centrum has extremely weak pleurocoels. Anterior caudals are procoelous, neural spines are simple in morphology, and diapophyses are not excessively developed. Medial caudals have bifurcated haemal arches and on the most posterior caudals prezygapophyses and neural spines remain present. The anteroproximal margin of the scapula is appropriately dorsally oblique, there is a conspicuous process on the posterior margin dorsal to the glenoid fossa, the coracoid is semi-elliptical and is in contact with the scapula with a relatively straight suture line.
The clavicle is arched with one end narrow and bifurcated and the other end broad and flat. The humerus is approximately three-quarters the length of the femur and the ulna is two-thirds the length of the humerus. The ilium resembles the basic morphology of Omeisaurus and Mamenchisaurus, the pubic peduncle is robust and situated at the midpoint of the ilium, an ischiac peduncle is indistinct, proximal ischium is distinctly broadened, the shaft is elongated, and the distal end is thin.
Source: Polyglot Paleontologist