''Lavocatavis'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of phorusrhacoid or "terror bird" from the

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

Algeria ) , image_map = Algeria (centered orthographic projection).svg , map_caption = , image_map2 = , capital = Algiers , coordinates = , largest_city = capital , relig ...

. A fossilized

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with ...

was described from the

Glib Zegdou Formation GLib is a bundle of three (formerly five) low-level system libraries written in C and developed mainly by GNOME. GLib's code was separated from GTK, so it can be used by software other than GNOME and has been developed in parallel ever sin ...

2011 File:2011 Events Collage.png, From top left, clockwise: a protester partaking in Occupy Wall Street heralds the beginning of the Occupy movement; protests against Libyan dictator Muammar Gaddafi, who was killed that October; a young man celebrate ...

and is the only known specimen of ''Lavocatavis''. The species was designated ''L. africana''.

Discovery and naming

The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

of ''Lavocatavis'', UM HGL 51-55, consists of an almost complete right femur. It is reasonably well preserved in the middle, but fragmentary at both ends. It originates from layer HGL 51 of the Glib Zegdou Formation of Algeria. The generic epithet (meaning "Lavocat's bird") was named in honor of René Lavocat, the person who first reported the earth layer of the holotype.

Paleobiogeography

The oldest phorusrhacoids are from South America and Antarctica, suggesting that the ancestors of ''Lavocatavis'' migrated into Africa from the west. During the Eocene, the Atlantic Ocean separated South America from Africa by at least , ruling out a land migration. For a flightless terrestrial bird like ''Lavocatavis'', the only means of entering Africa would have been through rafting on

floating island A floating island is a mass of floating aquatic plants, mud, and peat ranging in thickness from several centimeters to a few meters. Floating islands are a common natural phenomenon that are found in many parts of the world. They exist less co ...

s or

island hopping Leapfrogging, also known as island hopping, was a military strategy employed by the Allies in the Pacific War against the Empire of Japan during World War II. The key idea is to bypass heavily fortified enemy islands instead of trying to captu ...

. Currents traveled westward in the South Atlantic during the early Paleocene, making it unlikely that phorusrhacoids traveled on floating islands. The ancestors of ''Lavocatavis'' most likely traveled between very large islands that existed on what are now the submerged

Rio Grande Rise The Rio Grande Rise, also called the Rio Grande Elevation or Bromley Plateau, is an aseismic ocean ridge in the southern Atlantic Ocean off the coast of Brazil. Together with the Walvis Ridge off Africa, the Rio Grande Rise forms a V-shaped str ...

and

Walvis Ridge The Walvis Ridge (''walvis'' means whale in Dutch and Afrikaans) is an aseismic ocean ridge in the southern Atlantic Ocean. More than in length, it extends from the Mid-Atlantic Ridge, near Tristan da Cunha and the Gough Islands, to the Africa ...

. However, it is also possible that the ancestors of ''Lavocatavis'' retained some of their flight ability and were able to travel between islands with more ease than flightless birds. If this was the case, ''Lavocatavis'' became flightless independently of other flightless phorusrhacoids, in a case of

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

References

Extinct flightless birds Eocene birds Fossil taxa described in 2011 Phorusrhacidae Cenozoic birds of Africa {{paleo-bird-stub