New didactyl dinosaur footprints (Dromaeosauripus hamanensis ichnogen. et ichnosp. nov.) from the Early Cretaceous Haman Formation, south coast of Korea

Didactyl dinosaur footprints in fine-grained sandstone of the Early Cretaceous Haman Formation, Namhae area, Korea are herein described. The tracks are ~ 15 cm long and ~ 9.0 cm wide and consist only of impressions of digits III and IV, which show well-developed pad impressions. Digit impressions are narrow (about 2.0 cm), and terminate in sharp claw traces. Trackway width is very narrow, about 10.0 cm. Step length is about 92 cm and stride is about 185 cm. Pace angulation is about 180°, i.e., consecutive tracks are nearly in a straight line. The tracks are thought to have been made by a dromaeosaurid characterized by a strongly recurved, pes digit II that did not register on the substrate. dactyl trackway is attributed to a small dromaeosaurid (Deinonychosauria) running bipedally with a speed of 17.5 km/h on a lake margin. The didactyl tracks, described herein as Dromaeosauripus hamanensis ichnogen. et ichnosp. nov. represent only the fourth convincing record of didactyl tracks attributable to a member of the Deinonychosauria in the world, and the first in Korea. The report also provides significant information about the hip height, body size, foot morphology, walking or running speed, paleoecology, and paleogeography of dromaeosaurids that flourished during the Early Cretaceous in northeast Asia.