Gasosaurus

Type Species: Gasosaurus constructus

Classification: Dinosauria – Saurischia – Theropoda – Tetanurae

Time Period: Middle Jurassic

Location: China

Diet: Carnivore

Gasosaurus’ name literally means ‘gas lizard.’ This isn’t because it had swollen bowels and was necessarily gassy, though that would be fascinating if it were true. In reality, it’s named after the gasoline company that found it while doing construction in Sichuan Province, China. The discovery of this carnivorous theropod clued scientists in to a new bone-bed dating to the Middle and early Late Jurassic. During the Jurassic Period, the area had been a forested lakeside environment, and further digs after Gasosaurus’ unearthing have revealed all sorts of sauropods, theropods, and stegosaurs. The bone-bed is known as the Shaximiao Formation, and it’s divided into an Upper and Lower portions. The ‘Upper’ bone-bed correlates with the Oxfordian stage of the Late Jurassic while the ‘Lower’ bone-bed correlates with the Bathonian and Callovian stages of the Middle Jurassic. Gasosaurus emerged at the beginning of the Middle Jurassic and remained a staple of the Asian ecosystem into the beginning of the Early Jurassic; its ten-million-year ‘reign’ lasted from about 170-160 million years (a pretty good run for a single species!). 

Gasosaurus was a ‘stiff-tailed’ tetanuran theropod that measured eleven to thirteen feet and likely weighed around 330 to 880 pounds. It had strong legs but short arms, and it shares characteristics with both more developed tetanuran theropods and earlier non-tetanurans, suggesting that Gasosaurus was near the ‘base’ of the emerging tetanurans. It coexisted with other mid-range theropods such as Chuandongocoelurus and Kaijiangosaurus, both theropods found in the Lower Shaximiao Formation. Though it probably subsisted mostly on small- to medium-sized prey, it could have theoretically taken down the more primitive sauropods in its environment, especially if it utilized pack-hunting. In the artistic depiction below, two Gasosaurus are running in the midst of a Shunosaurus herd. Though Gasosaurus and Shunosaurus co-existed, they did so for only the briefest moment at the twilight of Gasosaurus’ prehistoric career.