because they were ground-dwelling animals not able to fly. In the case of the primitive birds Confuciusornis, they could not fly at all for long periods. In modern birds these structures, with the addition of fats, help to regulate body temperature during active flight. In addition, the identified corneocytes structures seem to indicate that non-avian dinosaurs had a similar way of shedding skin to extant birds and mammals. Unlike many reptiles alive today (lizards or snakes) which shed their skin as a single piece or as several large pieces, Beipiaosaurus and other non-avian dinosaurs shed their skin as dandruff, like Confuciusornis, modern birds or mammals. Paleoecology Studies suggest that the paleoenvironment of the Yixian Formation involved seasonal climate fluctuations, and was warm and humid, punctuated by dry seasons, in which the environment became more arid. The average yearly temperature during the time of Beipiaosaurus was , with relatively cold winters for the generally warm Mesozoic era. A study by Wu et al. 2013 concluded that orbital forcing, which is the effect on climate caused by shifts in the tilt of the Earth's axis and by the shape of the Earth's orbit, contributed to the climate fluctuations of this formation. The Yixian Formation is well known for its great diversity of well-preserved specimens and its dinosaurs, such as the tyrannosauroids Dilong and Yutyrannus, the dromaeosaurids Sinornithosaurus, oviraptorosaurs including Caudipteryx, compsognathids including Sinocalliopteryx, avialans including Confuciusornis and some non-theropod dinosaurs, such as Psittacosaurus and Dongbeititan. Other contemporaries of Beipiaosaurus included ancient shrimp, snails and slugs, as well as a diverse group of insects, and fish such as Lycoptera. Most vertebrates in this formation showed a tendency to become arboreal, including many tree-dwelling birds, and climbing mammals and lizards. The flora was dominated by conifers related to modern species that are found mainly in subtropical and temperate upland forests, with the presence of ferns, cycads, and horsetails. See also Timeline of therizinosaur research Falcarius References External links Dinosauria - News of the first Beipiaosaurus discovery. Skeletal restoration Therizinosauroidea - UCMP, Berkeley Detailed skull of STM 31-1 at Sketchfab Early Cretaceous dinosaurs of Asia Yixian fauna Feathered dinosaurs Fossil taxa described in 1999 Therizinosaurs Taxa named by Xu Xing