Fregatidae

Frigatebirds are a family of seabirds called Fregatidae which are found across all tropical and subtropical oceans. The five extant species are classified in a single genus, Fregata. All have predominantly black plumage, long, deeply forked tails and long hooked bills. Females have white underbellies and males have a distinctive red gular pouch which they inflate during the breeding season to attract females. Their wings are long and pointed and can span up to , the largest wing area to body mass ratio of any bird.

Limnofregata ("Freshwater frigatebird") is an extinct genus of primitive frigatebird. The two known species were described after fossils from the Early Eocene Green River Formation (c. 49 million years ago) of Wyoming. A number of good complete and partial skeletons, some with feather impressions, are known of the type species, Limnofregata azygosternon, and L. hasegawai is known from two skulls and most of one torso.