A New Semi-Palmate Bird Track, Gyeongsangornipes lockleyi ichnogen. et ichnosp. nov., and Koreanaornis from the Early Cretaceous Jindong Formation of Goseong County, Southern Coast of Korea

Abstract

Well-preserved semi-palmate bird tracks and small wading bird tracks from the Early Cretaceous Jindong Formation of Deokmyeongri, Hai-myeon, and Naesanri, Donghae-myeon, Goseong County, South Gyeongsang Province, southern coast of Korea, are herein described as Gyeongsangornipes lockleyi ichnogen. et ichnosp. nov. and Koreanaornis hamanensis, respectively. Gyeongsangornipes lockleyi is a small asymmetrical, strong mesaxonic bird track, about 31–32 mm long and 40–41 mm wide, without a clear hallux impression. Divarication between digits II and III is much larger than that between digits III and IV. Webbing is clearly preserved, and the web between digits II and III is smaller than that between digits III and IV, which shows strong asymmetry of web development. Two different-sized Gyeongsangornipes lockleyi appear to suggest two different-size classes of web-footed birds. Koreanaornis hamanensis is a small sub-symmetrical wading bird track, about 26–28 mm long and 29–39 mm wide, without clear hallux impressions. The divarication between digits II and III (59°–66°)°) is larger than that between digits III and IV (44°– 58°). Divarication between digits II and IV is 103°–123°. Length of digit III (26–28 mm) is longer than those of digits II and III (about 18 mm). These new records shed light on patterns of bird track diversity and abundance in the Cretaceous of Korea and document a diverse avian fauna that flourished during the Cretaceous.