A new avian ichnotaxon from the Cretaceous of Nei Mongol, China

The new bird track Tatarornipes chabuensis ichnogen et. ichnosp nov. is described from the Lower Cretaceous Jingchuan Formation of Inner Mongolia. This ichnospecies is abundant in the well-studied Chabu area of central Inner Mongolia (Nei Mongol). In addition to the type locality (Chabu site 4), large samples are known from Chabu sites 1, 5 and 15, and the ichnogenus also occurs in the Cretaceous of Shandong Province. More than 50 well-preserved, measured tracks and representative trackways from five samples are illustrated to show diagnostic features and modifications attributable to preservation. The ichnospecies, which is characterized by robust digits that are unusually wide proximally, is easily distinguished from smaller Cretaceous avian ichnotaxa such as Koreanaornis and Aquatilavipes, which are smaller and more gracile in appearance. Tatarornipes also reveals a distinctive trackway pattern often characterized by long steps and minimal pes rotation. This ichnogenus is typically found in fluvio-lacustrine settings in association with saurischian (theropod and sauropod) dominated footprint assemblages.