''Titanis'' was an extinct

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 giant

flightless Flightless birds are birds that through evolution lost the ability to fly. There are over 60 extant species, including the well known ratites (ostriches, emu, cassowaries, rheas, and kiwi) and penguins. The smallest flightless bird is the ...

terror birds Phorusrhacids, colloquially known as terror birds, are an extinct clade of large carnivorous flightless birds that were one of the largest species of apex predators in South America during the Cenozoic era; their conventionally accepted temporal ...

that inhabited

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

during the early

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

epochs. The

generic Generic or generics may refer to: In business * Generic term, a common name used for a range or class of similar things not protected by trademark * Generic brand, a brand for a product that does not have an associated brand or trademark, other ...

name, ''Titanis'', refers to the titans, Ancient Greek gods that preceded the

Twelve Olympians upright=1.8, Fragment of a relief (1st century BC1st century AD) depicting the twelve Olympians carrying their attributes in procession; from left to right: Hestia (scepter), Hermes (winged cap and staff), Aphrodite (veiled), Ares (helmet and s ...

, in allusion to the bird's size. The

specific Specific may refer to: * Specificity (disambiguation) * Specific, a cure or therapy for a specific illness Law * Specific deterrence, focussed on an individual * Specific finding, intermediate verdict used by a jury in determining the fina ...

name, ''T. walleri'', honors 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 ...

's collector, Benjamin I. Waller, an avocational underwater archaeologist. ''Titanis'' was thought to be carnivorous and most likely preyed on the many small

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

s of the time period. This giant flightless bird was one of the most efficient predators of its time in North America.

Description

''Titanis'' was approximately tall and around in weight. When compared with other

phorusrhacid Phorusrhacids, colloquially known as terror birds, are an extinct clade of large carnivorous flightless birds that were one of the largest species of apex predators in South America during the Cenozoic era; their conventionally accepted temporal ...

s, the examined material indicates a large variation in the size of ''Titanis'', perhaps indicating strong

sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

. It had long, agile legs, and three-toed feet with long

talon Talon or talons may refer to: Science and technology * Talon (anatomy), the claw of a bird of prey * Brodifacoum, a rodenticide, also known as the brand Talon * TALON (database), a database maintained by the US Air Force * Talon, an anti-vehicle- ...

s. It could undoubtedly run at high speeds when hunting. Though its skull has not been found, it most probably would have been large, with a huge, axe-like beak, like its relatives. Overall, ''Titanis'' was very similar to the South American ''

Phorusrhacos ''Phorusrhacos'' ( ) is an extinct genus of giant flightless terror birds that inhabited Argentina during the Miocene epoch. ''Phorusrhacos'' was one of the dominant land predators in South America at the time it existed. It is thought to have ...

'' and ''

Devincenzia ''Devincenzia'' is an extinct genus of giant flightless predatory birds in the family Phorusrhacidae or "terror birds" that lived during the Early Miocene (Deseadan) Fray Bentos Formation of Uruguay and Late Miocene (Huayquerian) Ituzaingó Form ...

'', its closest relatives. However, it differs from these in having a shorter, thicker neck, and an overall more heavily built bodily structure. Little is known of its body structure, but it seems to have been less wide-footed than ''Devincenzia'', with a proportionally much stronger middle toe.

Wings

The wings were small and could not have been used for flight. The wing bones articulated in an unusual joint-like structure, suggesting the digits could flex to some degree. It also had a relatively rigid wrist, which would not have allowed the hand to fold back against the arm to the same degree as other birds. This led R. M. Chandler to suggest that the wings may have supported some type of clawed, mobile hand similar to the hands of non-avian

theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...

dinosaurs, such as the

dromaeosaurs Dromaeosauridae () is a family of feathered theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek ('), meaning ...

(also popularly known as "raptors"). However, it was later pointed out that this wing joint is not in fact unique, and is present in

seriema The seriemas are the sole living members of the small bird family Cariamidae, which is also the only surviving lineage of the order Cariamiformes. Once believed to be related to cranes, they have been placed near the falcons, parrots and passerin ...

s (extant members of the same order,

Cariamae Cariamiformes (or Cariamae) is an order of primarily flightless birds that has existed for over 60 million years. The group includes the family Cariamidae (seriemas) and the extinct families Phorusrhacidae, Bathornithidae, Idiornithidae and A ...

, to which ''Titanis'' and other phorusrhacids belonged), which do not have any specialized grasping hands.

Discovery

The first described fossils of ''Titanis'' were collected in 1961 by Benjamin Waller in a site dating to the

Blancan The Blancan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 4,750,000 to 1,806,000 years Before Present, BP, a period of .

in the Santa Fe River on the county borderland between Gilchrist and Columbia Counties in Florida, the first Phorusrhacid fossils found in North America. The fossils were fragmentary and from several different individuals, including the distal end of a tarsometatarus (UF-4108) that was associated with a phalanx 1 of digit 3 from the foot. The It lived approximately 5 to 2 million years ago (early Pliocene to early Pleistocene) in North America. Fossil evidence has been found in three locations in Florida and one in Texas. The

Gilchrist County, Florida Gilchrist County is a county located in the north central part of the U.S. state of Florida. Organized in 1925 from the western part of Alachua, it is the last county to be formed in the state. As of the 2020 census, the population was 17,86 ...

site dates from 3.0 to 2.9 million years ago. The Santa Fe River, where 27 of the 41 ''Titanis'' fossil specimen have been found, is located in Gilchrist County. The other locations that ''Titanis'' has been found include Port Charlotte and Inglis, Florida. Only one specimen has been found outside of Florida, and that was in the

Nueces River The Nueces River is a river in the U.S. state of Texas, about long. It drains a region in central and southern Texas southeastward into the Gulf of Mexico. It is the southernmost major river in Texas northeast of the Rio Grande. ''Nueces'' ...

in Texas.

Classification

''Titanis'' was part of the group of giant flightless birds called the

Phorusrhacidae Phorusrhacids, colloquially known as terror birds, are an extinct clade of large carnivorous flightless birds that were one of the largest species of apex predators in South America during the Cenozoic era; their conventionally accepted temporal ...

, which are nicknamed "terror birds". It was thought to represent the youngest species of the lineage but recently, a significantly younger South American example has been reported. The Phorusrhacidae originated in South America; ''Titanis'' is the only known member of the branch of the group that migrated out of that continent during the

Great American Interchange The Great American Biotic Interchange (commonly abbreviated as GABI), also known as the Great American Interchange and the Great American Faunal Interchange, was an important late Cenozoic paleozoogeographic biotic interchange event in which lan ...

. A lineage of related predatory birds, the

bathornithids Bathornithidae is an extinct family of birds from the Eocene to Miocene of North America. Part of Cariamiformes, they are related to the still extant seriemas and the also extinct Phorusrhacidae. They were likely similar in habits, being terrestr ...

, occurred in North America from the

Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), E ...

to the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

. They were not ancestral to ''Titanis'' or any other phorusrhacid, but they occupied similar ecological niches and some like ''

Paracrax ''Paracrax'' ("near curassow") is a genus of extinct North American flightless birds, possibly related to modern seriemas and the extinct terror birds. Part of Bathornithidae (though some analysis recover it as closer to the living seriemas inst ...

'' even attained similar sizes, reaching above 2 meters in height. They became extinct more or less 15 million years before ''Titanis'' reached North America. The only living relatives of ''Titanis'' are the

Paleobiology

Studies of the closely related '' Andalgalornis steulleti,'' which is also in the family

reveals new information about the head and neck movement of ''T. walleri'' and all "terror birds" of this family. In a series of tests on the skull of ''Andalgalornis'', it was found that these birds would have had a hard time moving their heads laterally. However, the back and forth movement of the skull was tremendous, and it is thought that ''Titanis'' most likely used its massive skull to pummel prey to death.

Extinction

The extinction of ''T. walleri'' and other

s throughout the

Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with th ...

may have resulted from competition with large

placental Placental mammals (infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupial Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsup ...

(

canid Canidae (; from Latin, ''canis'', "dog") is a biological family of dog-like carnivorans, colloquially referred to as dogs, and constitutes a clade. A member of this family is also called a canid (). There are three subfamilies found within the ...

felid Felidae () is the family of mammals in the order Carnivora colloquially referred to as cats, and constitutes a clade. A member of this family is also called a felid (). The term "cat" refers both to felids in general and specifically to the dom ...

, and possibly ursid)

carnivores A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...

that radiated in the same ancient terrestrial ecosystems during the

. However, this has been contested as ''Titanis walleri'' had competed successfully against both groups for several million years upon entering North America. From circumstantial evidence (i.e., bone fractures), it has been suggested that the species did not become extinct until 15,000 years ago, but more precise dating by McFadden and colleagues refutes such a late date; all known ''Titanis'' fossils appear to be at least 2 million years old.

References

External links

* dinosoria.com
''Titanis walleri'' reconstructions
Retrieved 2007-FEB-09. * * Discover Magazine, June 1997
Terror Take Two
{{Taxonbar, from=Q427685 Extinct flightless birds Bird genera Phorusrhacinae Pleistocene genus extinctions Pliocene birds of North America Pleistocene birds of North America Fossil taxa described in 1963 Taxa named by Pierce Brodkorb