Ornimegalonyx (also known as the Cuban Giant Owl or Cuban Cursorial Owl) is a genus of giant owl from Pleistocene Cuba. It is the largest owl to have ever existed.
The height of Ornimegalonyx is estimated to have been about 1.1 meters, and its weight over 9 kilograms. Its legs and feet were very large and well-built, and likely adapted for running.
Ornimegalonyx was originally described in 1954 by Oscar Arredondo, who identified it as a type of terror bird due to its size. In 1961, Pierce Brodkorb found the fossils to be those of a giant owl. Remains of Ornimegalonyx are common in Cuba, and four species in total have been described.
- Arredondo, Oscar (1976) translated Olson, Storrs L. "The Great Predatory Birds of the Pleistocene of Cuba" pp. 169-187 in "Smithsonian Contributions to Paleobiology number 27; Collected Papers in Avian Paleontology Honoring the 90th Birthday of Alexander Wetmore"
- Arredondo, Oscar (1982). Los Strigiformes fósiles del pleistoceno cubano. Boletín de la Sociedad Venezolana de Ciencias Naturales 140, 33-55.
- Andrews, Peter (1990) "Owls, Caves, and Fossils: Predation, Preservation, and Accumulation of Small Mammal Bones in Caves, with an Analysis of the Pleistocene Cave Faunas from Westbury-sub-Mendip, Somerset, UK" University of Chicago Press. 231pages. ISBN 0-226-02037-1, ISBN 978-0-226-02037-2