enaliornithines
Enaliornithines are an extinct group of seabirds that lived during the Eocene epoch. Their fossil remains are primarily found in the London Clay Formation of England. These birds are notable for their adaptations to a marine lifestyle, suggesting they were proficient swimmers and divers. While their exact evolutionary relationships are debated, they are generally considered to be part of the order Pelecaniformes, which includes modern pelicans and their allies. The name "enaliornithines" derives from Greek words meaning "sea birds," reflecting their inferred habitat. Fossil evidence indicates they possessed long, pointed beaks, likely used for catching fish and other small marine prey. The size of enaliornithines varied, with some species estimated to be comparable in size to modern gulls or larger seabirds. Their presence in the Eocene London Clay suggests a thriving coastal ecosystem during that period. The precise reasons for their extinction remain unclear, but likely involved environmental changes or competition with other marine birds that evolved later.