Lower Cretaceous Dinosaur Trackways Exposed by Water Erosion in Sichuan Province, China

A newly discovered saurischian dominated tracksite in the Lower Cretaceous Jiaguan Formation in southeastern Sichuan province reveals 13 sauropod trackway segments representing ichnogenus Brontopodus and three theropod trackways. This is a typical Type 1 Jiaguan Formation deposit dominated by tetrapod tracks with no significant tetrapod body fossils. The tracks occur in a river channel exposure of feldspathic quartz sandstone about 20–25 m wide and ~ 60 m long. The trackways are exposed on both banks but eroded away in the central channel area. The sauropod tracks represent relatively small animals with pes print lengths ranging from 24.5 cm to 33.9 cm. The theropod trackways include a large example (footprint length 46.5 cm with metatarsal traces) and two smaller parallel trackways with footprint lengths less than 20 cm. The author also discussed the erosion of tracks and trackways by water erosion, especially their morphological changes.