Hypnogyra

Hypnogyra is a genus of extinct scleractinian corals belonging to the family Agariciidae. Fossils of Hypnogyra species have been found in various locations, including Europe and the Caribbean, and date back to the Paleocene and Eocene epochs (approximately 66 to 34 million years ago).

Characteristics of Hypnogyra corals generally include laminar or encrusting growth forms. The corallites, which are the skeletal cups that house the coral polyps, are typically small and shallow. The surface of the coral often exhibits a distinctive wavy or undulating pattern. The septa, the vertical plates inside the corallites, are generally thin and closely spaced.

The extinction of Hypnogyra is likely linked to global environmental changes that occurred during the Eocene-Oligocene transition, a period characterized by significant cooling and changes in ocean chemistry.

The study of Hypnogyra is important for understanding the evolution and paleoecology of coral reefs and the impact of past climate change on marine ecosystems. Paleontologists use fossil Hypnogyra specimens to reconstruct ancient reef environments and to trace the evolutionary relationships between different coral groups.