The Middle–Upper Jurassic dinosaur-pterosaur fauna in Shandong Province, China: Evidence from ichnology

Tracks previously examined between 2002 and 2015 from an incompletely-studied, and now partially lost tracksite site in the Santai Formation of Shandong Province were restudied based on new excavations of additional surfaces. In contrast to the previous reports of tridactyl tracks, including Grallator, the present study discovered an additional assemblage of unequivocal pterosaur tracks (Pteraichnus) and a possible didactyl deinonychosaurian track. The age of the Santai Formation is controversial but it is probably Late Jurassic, which corresponds to the epoch when pterosaur tracks appear worldwide. Age interpretations, based on palynology and isotopic data, tentatively suggests an earlier Middle-Late Jurassic age and might suggest that the pterosaurian tracks are as old or somewhat older than any previously reported.