Caudipteryx

Caudipteryx is a landmark Early Cretaceous theropod unearthed from the lake deposits of the Yixian Formation in Liaoning, China. About the size of a turkey, it provided some of the earliest conclusive proof that non-flying dinosaurs sported true modern-style vaned feathers. Its forelimbs bore symmetrical plumes and its abbreviate tail terminated in an elegant feather fan, yet its short arms and body proportions show that it was entirely flightless. Instead, these feathers likely functioned in display, egg brooding, or turning stability while sprinting. Preserved specimens regularly contain clusters of gastroliths in their abdominal regions, showing that Caudipteryx used swallowed stones to grind tough vegetation or seeds, though it probably opportunistically consumed small invertebrates as well. Its discovery in the late 1990s fundamentally reshaped scientific consensus regarding the evolutionary link between dinosaurs and modern birds.

It possessed a fan of vaned feathers on a short tail and preserved stomach stones used to grind plants.

Where and when

Caudipteryx lived in the Early Cretaceous, from 125.8 to 122.5 million years ago (Barremian-Aptian age). Its remains come from China, in the Yixian Formation.

The numbers

Length 0.9 m (estimates run from 0.7 to 1 m). Mass about 3.2 kg. Hip height about 0.4 m. That is 0.5 human-lengths, or 0.08 of a double-decker bus. These are estimates from near-complete skeleton; fields marked estimated by the site are length, mass, hip height.

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