Original Paper


, Volume 94, Issue 8, pp 657-665

First online:

Earliest zygodactyl bird feet: evidence from Early Cretaceous roadrunner-like tracks

  • Martin G. LockleyAffiliated withDinosaur Tracks Museum, University of Colorado at Denver Email author 
  • , Rihui LiAffiliated withQingdao Institute of Marine Geology, China Geological Survey
  • , Jerald D. HarrisAffiliated withScience Department, Dixie State College
  • , Masaki MatsukawaAffiliated withDepartment of Environmental Sciences, Tokyo Gakugei University
  • , Mingwei LiuAffiliated withFourth Geological and Mineral Resources Survey of Shandong

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Fossil footprints are important in understanding Cretaceous avian diversity because they constitute evidence of paleodiversity and paleoecology that is not always apparent from skeletal remains. Early Cretaceous bird tracks have demonstrated the existence of wading birds in East Asia, but some pedal morphotypes, such as zygodactyly, common in modern and earlier Cenozoic birds (Neornithes) were unknown in the Cretaceous. We, herein, discuss the implications of a recently reported, Early Cretaceous (120–110 million years old) trackway of a large, zygodactyl bird from China that predates skeletal evidence of this foot morphology by at least 50 million years and includes the only known fossil zygodactyl footprints. The tracks demonstrate the existence of a Cretaceous bird not currently represented in the body fossil record that occupied a roadrunner (Geococcyx)-like niche, indicating a previously unknown degree of Cretaceous avian morphological and behavioral diversity that presaged later Cenozoic patterns.


Zygodactyl Cretaceous Roadrunner China Evolution Diversity