An incomplete skeleton of Pliosauroidea from the Middle Jurassic of Zigong, Sichuan, is described in this paper. The main features of the new specimen (ZDM 0185) can be summarized as follows: Individual is medium size...An incomplete skeleton of Pliosauroidea from the Middle Jurassic of Zigong, Sichuan, is described in this paper. The main features of the new specimen (ZDM 0185) can be summarized as follows: Individual is medium size. Dorsal vertebrae are amphicoelous, without ventral ridge. Dorsal neural spines are plate like. Sacral ribs are small, with thin and plate like distal end. Ilium is small, with thin sacral end and thick acetabulum end. The puboischiatic fenestra is oval in outline. Tibia is about 2/5 as long as the length of femur. Fibula is shorter than tibia. Pes has five metatarsals, in which metatarsal I, V are relatively thin and metatarsal II, III, IV are thick. There are 8 phalanges in digit 5. In view of above features, the new specimen should be included in Bishanopliosaurus . Comparison of ZDM 0185 with Bishanopliosaurus youngi , some differences are present: The sacral end of ilium is small, its width is 58%～62% of the acetabulum end. Tibia is about 2/5 as long as the length of femur. The front border of acetabulum end of pubis with a concavity. Sacral ribs are small, with thin and plate like distal end in ZDM 0185. The width of the sacral end is 86% of the acetabulum end. Tibia is about 1/3 as long as the length of femur. The front border of acetabulum end of the pubis without a concavity. The sacral ribs are bifurcated in Bishanopliosaurus youngi . Therefore, we suggest that ZDM 0185 is named a new species of Bishanopliosaurus—B. zigongensis sp. nov.展开更多
文摘An incomplete skeleton of Pliosauroidea from the Middle Jurassic of Zigong, Sichuan, is described in this paper. The main features of the new specimen (ZDM 0185) can be summarized as follows: Individual is medium size. Dorsal vertebrae are amphicoelous, without ventral ridge. Dorsal neural spines are plate like. Sacral ribs are small, with thin and plate like distal end. Ilium is small, with thin sacral end and thick acetabulum end. The puboischiatic fenestra is oval in outline. Tibia is about 2/5 as long as the length of femur. Fibula is shorter than tibia. Pes has five metatarsals, in which metatarsal I, V are relatively thin and metatarsal II, III, IV are thick. There are 8 phalanges in digit 5. In view of above features, the new specimen should be included in Bishanopliosaurus . Comparison of ZDM 0185 with Bishanopliosaurus youngi , some differences are present: The sacral end of ilium is small, its width is 58%～62% of the acetabulum end. Tibia is about 2/5 as long as the length of femur. The front border of acetabulum end of pubis with a concavity. Sacral ribs are small, with thin and plate like distal end in ZDM 0185. The width of the sacral end is 86% of the acetabulum end. Tibia is about 1/3 as long as the length of femur. The front border of acetabulum end of the pubis without a concavity. The sacral ribs are bifurcated in Bishanopliosaurus youngi . Therefore, we suggest that ZDM 0185 is named a new species of Bishanopliosaurus—B. zigongensis sp. nov.
