First record of a complete giant theropod egg clutch from Upper Cretaceous deposits, South Korea

Abstract

Here, we report the first occurrence of a complete Macroelongatoolithus clutch from outside of China. Excavated from Upper Cretaceous strata of Aphae-do in Shinan-gun, Jeollanam-do Province, South Korea, the clutch of 19 eggs is characterised by large, elongate, symmetrical eggs arranged in a single-layered ring-shaped clutch. Eggs are inclined towards the centre of the 2.3-m diameter clutch, and average 41.17 cm long and 15.58 cm wide. Of the 19 eggs, 8 clearly retain a paired configuration. This specimen represents only the second report of large theropod eggs from South Korea and is the most complete Macroelongatoolithus clutch known from the region to date. Eggshell microstructural features are consistent with Macroelongatoolithus xixiaensis (oofamily Elongatoolithidae), previously known only from Cenomanian strata of southeastern China. This first record of a giant theropod egg clutch, here assigned to M. xixiaensis, extends the stratigraphic and paleogeographic range of Macroelongatoolithus eggs and parent animals to include the Campanian of South Korea.