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''Teratornis'' (Greek: "wonder" (teratos), "bird" (ornis)) is an extinct
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of huge
North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
n
birds of prey Birds of prey or predatory birds, also known as (although not the same as) raptors, are hypercarnivorous bird species that actively predation, hunt and feed on other vertebrates (mainly mammals, reptiles and smaller birds). In addition to speed ...
—the best-known of the
teratorns Teratornithidae is an extinct family (biology), family of very large Bird of prey, birds of prey that lived in North and South America from the Oligocene, Late Oligocene to Pleistocene, Late Pleistocene. They include some of the largest known fly ...
—of which, two species are known to have existed: ''Teratornis merriami'' and ''Teratornis woodburnensis''. A large number of
fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...
and
subfossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
bones, representing more than 100 individuals, have been found in locations in
California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
,
Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...
, southern
Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...
,
Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...
, and
Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...
, though most are from the Californian
La Brea Tar Pits La Brea Tar Pits comprise an active Paleontological site, paleontological research site in urban Los Angeles. Hancock Park was formed around a group of tar pits where natural Bitumen, asphalt (also called asphaltum, bitumen, or pitch; ''brea'' ...
. All remains except one
Early Pleistocene The Early Pleistocene is an unofficial epoch (geology), sub-epoch in the international geologic timescale in chronostratigraphy, representing the earliest division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently esti ...
partial skeleton from the Leisey Shell Pit near
Charlotte Harbor, Florida Charlotte Harbor is a census-designated place (CDP) in Charlotte County, Florida, United States. The name Charlotte Harbor also refers to Charlotte Harbor (estuary) and Charlotte Harbor Preserve State Park, a preserve with of shoreline alon ...
(which may represent a different species or a subspecies) date from the
Late Pleistocene The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as the Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division ...
, with the youngest remains dating from the
Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...
Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...
boundary.


Taxonomy

* ''Teratornis merriami''. This is by far the best-known and most commonly found species. Up to a hundred specimens have been found, mostly from the
La Brea Tar Pits La Brea Tar Pits comprise an active Paleontological site, paleontological research site in urban Los Angeles. Hancock Park was formed around a group of tar pits where natural Bitumen, asphalt (also called asphaltum, bitumen, or pitch; ''brea'' ...
. It stood about 75 cm (29.5 in) tall with estimated wingspan of perhaps 3.5 to 3.8 metres (11.5 to 12.5 ft), and its weight has been estimated within the range of with 95% confidence; making it about a third bigger than extant condors. It became extinct at the very end of the Pleistocene, some 10,000 years ago. Before the formation of the Teratornithidae family, The ''T. merriami''s hooked beak and skull morphology led to its initial placement in the family Vulturidae alongside New World Vultures. Further analysis has suggested a potentially equal relation to storks in the Ciconiidae family. Despite similarities, these three families can be differentiated by their differing skulls in response to significantly different feeding methods. * ''Teratornis woodburnensis''.Campbell, Kenneth E. Jr. & Stenger, Allison T. (2002)
A New Teratorn (Aves: Teratornithidae) from the Upper Pleistocene of Oregon, USA
. pp. 1–11. in Zhou, Z. and F. Zhang. ''Proceedings of the 5th Symposium of the Society of Avian Paleontology and Evolution Beijing'', 1–4 June 2000. China Science Press, Beijing.
The first species to be found north of the La Brea Tar Pits, this partial specimen was discovered at Legion Park, Woodburn, Oregon in 1999. It is known from a humerus, parts of the cranium, beak, sternum, and vertebrae which indicate an estimated wingspan of over 4 meters (14 ft). The find dates to the late Pleistocene, about 12,000 years ago, in a stratum containing the remains of
megafauna In zoology, megafauna (from Ancient Greek, Greek μέγας ''megas'' "large" and Neo-Latin ''fauna'' "animal life") are large animals. The precise definition of the term varies widely, though a common threshold is approximately , this lower en ...
such as mammoth, mastodon, and ground sloths, as well as evidence of early human occupancy at the site. Another form, '' "Teratornis" olsoni'', was described from the Pleistocene of
Cuba Cuba, officially the Republic of Cuba, is an island country, comprising the island of Cuba (largest island), Isla de la Juventud, and List of islands of Cuba, 4,195 islands, islets and cays surrounding the main island. It is located where the ...
, but its affinities are not completely resolved; it might not be a teratorn, but has also been placed in its own genus, ''Oscaravis''. There are also undescribed fossils from southwestern
Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...
, but apart from these forms, teratorns were restricted to North America. A closely related genus, ''
Aiolornis ''Aiolornis incredibilis'' is an extinct species of teratorn bird from the western United States. Only fragmentary remains have been found, which are dated between the Early Pliocene (Zanclean) and Late Pleistocene. First described as ''Teratorni ...
'', was about 40% larger and lived at an earlier time; it was formerly known as ''Teratornis incredibilis'', but is distinct enough to be placed in its own genus.


Description

According to description of 1945, ''Teratornis merriami'' had a wingspan of around and a wing area of 17.5 square meters, standing an estimated tall. It was somewhat larger than the extant
Andean condor The Andean condor (''Vultur gryphus'') is a South American New World vulture and is the only member of the genus ''Vultur''. It is found in the Andes mountains and adjacent Pacific coasts of western South America. With a maximum wingspan of and ...
, and by calculating the area of the organism's sternum and synsacrum, ''Teratornis'' was estimated to weigh about , which was nearly double the weight of an average Californian condor. A 1983 study gives a range of wingspan of and a weight of . The finger bones of the Teratornis were fused as in all modern birds; however, part of the index finger forms a shelf which aided in bearing the load of long and stout
primaries Primary elections or primaries are elections held to determine which candidates will run in an upcoming general election. In a partisan primary, a political party selects a candidate. Depending on the state and/or party, there may be an "open pri ...
, enabling the bird to utilize strong upcurrents in flight. Their legs were similar to an Andean condor's, but stouter, and the feet could hold prey for tearing off pieces, but could not exert a very forceful grip like birds of prey. Its
wing loading In aerodynamics, wing loading is the total weight of an aircraft or flying animal divided by the area of its wing. The stalling speed, takeoff speed and landing speed of an aircraft are partly determined by its wing loading. The faster an airc ...
was not much larger than a Californian condor's, and Merriam's teratorn should have been able to take off by simply jumping and beating its wings under most circumstances. Indeed, it seems to have been better adapted for utilizing a short run into the wind from an elevated location as condors do, as its legs are proportionally smaller and its stride less than in condors. Thus, ''Teratornis'' may have primarily inhabited cliff terrain, where it could take off and soar through the air easily.


Paleobiology


Diet and feeding habits

The ''T. merriami'' was similar to
condor Condor is the common name for two species of New World vultures, each in a monotypic genus. The name derives from the Quechua language, Quechua ''kuntur''. They are the largest flying land birds in the Western Hemisphere. One species, the And ...
s, although an analysis of the functional
morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...
of its skull, namely its larger bill and ability to spread its mandibles and swallow its prey whole, suggests that it was an active and carnivorous predator rather than a scavenger. In fact, some studies of skull morphology indicated that the ''T.merriami'' were incapable of tearing pieces of flesh off of carcasses in the manner of condors. Alternative viewpoints note that many
old world vultures Old World vultures are vultures that are found in the Old World, i.e. the continents of Europe, Asia and Africa, and which belong to the family Accipitridae, which also includes eagles, buzzards, kites, and hawks. Old World vultures are not clo ...
possess large bills, and a longer bill is a common feature among scavenging raptors, as this allows them to probe deeper into large carcasses - larger than those fed upon by active-hunting raptors. Other anatomical features, such as the relatively small and sideward facing orbits and the low skull, are also consistent with a scavenging lifestyle. For the ''T.merriami'', small prey such as frogs, lizards, young birds, and small mammals were swallowed whole, while
carrion Carrion (), also known as a carcass, is the decaying flesh of dead animals. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
would have been fed on in a manner similar to that of condors or
vultures A vulture is a bird of prey that scavenges on carrion. There are 23 extant species of vulture (including condors). Old World vultures include 16 living species native to Europe, Africa, and Asia; New World vultures are restricted to North and ...
.


Locomotion

An analysis of the Teratorn pelvic girdle and stout, columnar hind leg bones suggests that its legs had greater anteroposterior ability than those of condors, and that the birds were agile and well-suited for walking and stalking prey on the ground similarly to storks and turkeys. On the other hand, their flight was similar to that of condors. Condors fly by means of soaring on rising up-currents, generally weak currents that are subject to sudden changes in direction or strength. Their ability to react to these changes and maintain flight has to do with their emarginated
primary feathers Flight feathers (''Pennae volatus'') are the long, stiff, asymmetrically shaped, but symmetrically paired pennaceous feathers on the wings or tail of a bird; those on the wings are called remiges (), singular remex (), while those on the tai ...
which separate and move independently during flight, contrary to the unemarginated primary feathers of birds who dynamically soar on more reliable air currents.


Habitat

''Teratornis'' had legs that were too short for it to take flight by running on flat ground. It is theorized that the Teratornis primarily inhabited cliff terrain, where it could take off and soar through the air easily. Many Teratorn bone samples contributing to modern research have been found at the
La Brea Tar Pits La Brea Tar Pits comprise an active Paleontological site, paleontological research site in urban Los Angeles. Hancock Park was formed around a group of tar pits where natural Bitumen, asphalt (also called asphaltum, bitumen, or pitch; ''brea'' ...
in Los Angeles, California. Teratorns are thought to have been attracted by
Pleistocene megafauna The Late Pleistocene to the beginning of the Holocene saw the extinction of the majority of the world's megafauna, typically defined as animal species having body masses over , which resulted in a collapse in faunal density and diversity acro ...
that became stuck and died in the viscous
asphalt Asphalt most often refers to: * Bitumen, also known as "liquid asphalt cement" or simply "asphalt", a viscous form of petroleum mainly used as a binder in asphalt concrete * Asphalt concrete, a mixture of bitumen with coarse and fine aggregates, u ...
while trying to drink from pools of water that gathered on the surface, with the teratorns subsequently falling victim to the sticky deposits. Merriam's Teratorn probably played an important role in opening up the body cavities of carcasses for smaller birds like
eagle Eagle is the common name for the golden eagle, bald eagle, and other birds of prey in the family of the Accipitridae. Eagles belong to several groups of Genus, genera, some of which are closely related. True eagles comprise the genus ''Aquila ( ...
s and
raven A raven is any of several large-bodied passerine bird species in the genus '' Corvus''. These species do not form a single taxonomic group within the genus. There is no consistent distinction between crows and ravens; the two names are assigne ...
s which are also known to have frequented the locality, as
mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...
ian predators-- being unable to fly-- could hardly reach most carcasses without getting mired in the asphalt themselves. However, there were also true
vultures A vulture is a bird of prey that scavenges on carrion. There are 23 extant species of vulture (including condors). Old World vultures include 16 living species native to Europe, Africa, and Asia; New World vultures are restricted to North and ...
present in the area at that time, and unlike those, ''T. merriami'' was also well adapted to hunt for smaller animals which are also known to have utilized the pools. Analysis of the skull and bill shapes suggests that fish may have constituted a major part of its diet. Taking into account the strong legs, stout claws, and a gripping power not quite as developed as in eagles, it is rather likely that Merriam's Teratorn would have hunted for aquatic prey in the manner of an
osprey The osprey (; ''Pandion haliaetus''), historically known as sea hawk, river hawk, and fish hawk, is a diurnal, fish-eating bird of prey with a cosmopolitan range. It is a large raptor, reaching more than in length and a wingspan of . It ...
, which also provides a reasonable explanation of how such large numbers of powerful, well-flying birds could have become stuck in the asphalt.


References

{{Taxonbar, from=Q137294 Bird genera Extinct animals of the United States Fossil taxa described in 1909 Late Quaternary prehistoric birds Pleistocene birds of North America Pleistocene birds Pleistocene genus extinctions Taxa named by Loye H. Miller Teratornithidae