Sinosauropteryx - Palaeoecology

Palaeoecology

Sinosauropteryx, as a Yixian Formation dinosaur, is a member of the Jehol Biota, the assemblage of organisms found in the Yixian Formation and overlying Jiufotang Formation. The Yixian Formation is composed largely of volcanic rocks such as andesite and basalt. Between the volcanic layers are several beds of sedimentary rocks representing deposition in a lake. The freshwater lake strata of the Yixian Formation have preserved a wide variety of plants, invertebrates, and vertebrates. Gymnosperm forests were extensive, with a few early flowering plants as well. Ostracods and insects were diverse, and bivalves and gastropods were abundant. Mammals and birds are also well-known from the formation. The setting was subject to periodic mortality events including volcanic eruptions, wildfires, and noxious gases erupting from the lakes. The climate has been interpreted as temperate, with distinct wet and dry seasons. The yearly temperature during this time period averaged about 10 degrees celsius (50 degrees Fahrenheit), indicating a temperate climate with unusually cold winters for the generally warm Mesozoic era, possibly due to northern China's high latitude during this time.