Andalgalornis | |
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CT scan of the skull of P 14357, holotype of A. ferox in the collections of the Field Museum of Natural History | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Cariamiformes |
Family: | † Phorusrhacidae |
Subfamily: | † Patagornithinae |
Genus: | † Andalgalornis Patterson & Kraglievich, 1960 |
Species: | †A. steulleti |
Binomial name | |
†Andalgalornis steulleti (Kraglievich, 1931) | |
Synonyms | |
List
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Andalgalornis is a genus of flightless predatory birds of the extinct family Phorusrhacidae (often called "terror birds") that lived in Argentina. The type and only species is A. steulleti.
Andalgalornis is known from an incomplete skeleton and some single bones found from sites in the Entre Ríos and Catamarca Provinces of northeast and northwest Argentina. The fossils were uncovered from the Late Miocene (Huayquerian in the SALMA classification) Ituzaingó Formation of the Paraná Basin. [1]
The following cladogram shows the position of Andalgalornis following a 2015 analysis: [2]
Phorusrhacidae |
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Around 1.4 metres (4.6 ft) tall in height, Andalgalornis is estimated to have weighed around 40 kilograms (88 lb), [3] on the basis of the methodology proposed by Campbell and Marcus (1992). [4] The subfamily to which the genus belonged, the Patagornithinae, contained species that were of quite slender build; it looked much like the larger phorusrhacid Phorusrhacos , but it was more elegant and smaller and had a proportionally higher beak, the most massive in proportion to body size of all phorusrhacids.
Phorusrhacids are though to have been ground predators or scavengers, and have often been considered apex predators that dominated Cenozoic South America in the absence of mammalian predators, though they did co-exist with some large, carnivorous borhyaenid mammals. Earlier hypotheses of phorusrhacid feeding ecology were mainly based on them possessing large skulls with hooked beaks rather than through detailed hypotheses and biomechanical studies, and such studies of their running and predatory adaptations were only tested from the beginning of the 21st century. [3] [5]
Alvarenga and Elizabeth Höfling made some general remarks about phorusrhacid habits in a 2003 article. They were flightless, as evidenced by the proportional size of their wings and body mass, and wing size was more reduced in larger members of the group. They pointed out that the narrowing of the pelvis, upper maxilla, and thorax may have been adaptations for hunting in regions with high vegetation, which would permit greater agility when moving between vertical obstacles. The narrow upper maxilla would also help catching small animals hidden among tree trunks or stones. The large expansions above the eyes formed by the lacrimal bones (similar to what is seen in modern hawks) would have protected the eyes against the sun, and enabled keen eyesight, which indicates they hunted by sight in open, sunlit areas, and not shaded forests. [6]
A 2010 study by Degrange and colleagues of Andalgalornis, based on Finite Element Analysis using CT scans, estimated its bite force and stress distribution in its 37-centimetre-long (15 in) skull, and showed that it had lost a large degree of intracranial immobility (mobility of skull bones in relation to each other), as was also the case for other large phorusrhacids. These researchers interpreted this loss as an adaptation for enhanced rigidity of the skull, and compared to the modern red-legged seriema and white-tailed eagle, the skull of the phorusrhacid showed relatively high stress under sideways loadings, but low stress where force was applied up and down, and in simulations of "pullback". Due to the relative weakness of the skull at the sides and middle, these researchers considered it unlikely that Andalgalornis engaged in potentially risky behavior that involved using its beak to subdue large, struggling prey. Instead, they suggested that it either fed on smaller prey that could be killed and consumed more safely, by, for example, swallowing it whole, or that when targeting large prey, it used a series of well-targeted repetitive strikes with the beak, in an "attack-and-retreat" strategy. Struggling prey could also be retained with the feet, despite the lack of sharp talons. [3]
A 2012 follow-up study by Tambussi and colleagues analyzed the flexion abilities of the neck of Andalgalornis, based on the morphology of its neck vertebrae, finding the neck to be divided into three sections. They concluded that the neck musculature and skeleton of Andalgalornis was adapted to carrying a large head, and for helping it rise after a maximum downwards strike, and the researchers assumed the same would be true for other large, big-headed phorusrhacids. [7] A 2020 study of phorusrhacid skull morphology by Degrange found that there were two main morphotypes within the group, derived from a seriema-like ancestor; the "Psilopterine Skull Type", which was plesiomorphic (more similar to the ancestral type), and the "Terror Bird Skull Type", which included Andalgalornis and other large members, that was more specialized, with more rigid and stiff skulls. Despite the differences, studies have shown the two types handled prey similarly, while the more rigid skulls and resulting larger bite force of the "Terror Bird" type would have been an adaptation to handling larger prey. [5]
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 passerines, as well as the extinct Phorusrhacidae. The seriemas are large, long-legged territorial birds that range from 70–90 cm (28–35 in) in length. They live in grasslands, savanna, dry woodland and open forests of Brazil, Bolivia, Argentina, Paraguay and Uruguay. There are two species of seriemas, the red-legged seriema and the black-legged seriema. Names for these birds in the Tupian languages are variously spelled as siriema, sariama, and çariama, and mean "crested".
Phorusrhacids, colloquially known as terror birds, are an extinct family of large carnivorous flightless birds that were among the largest apex predators in South America during the Cenozoic era; their conventionally accepted temporal range covers from 53 to 0.1 million years (Ma) ago.
Phorusrhacos is an extinct genus of giant flightless terror birds that inhabited South America 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 lived in woodlands and grasslands.
Titanis is a genus of phorusrhacid, an extinct family of large, predatory birds, in the order Cariamiformes that inhabited the United States during the Pliocene and earliest Pleistocene. The first fossils were unearthed by amateur archaeologists Benjamin Waller and Robert Allen from the Santa Fe River in Florida and were named Titanis walleri by ornithologist Pierce Brodkorb in 1963, the species name honoring Waller. The holotype material is fragmentary, consisting of only an incomplete right tarsometatarsus and phalanx, but comes from one of the largest phorusrhacid individuals known. In the years following the description, many more isolated elements have been unearthed from sites from other areas of Florida, Texas, and California. It was classified in the subfamily Phorusrhacinae, which includes some of the last and largest phorusrhacids like Devincenzia and Kelenken.
Brontornis is an extinct genus of giant bird that inhabited Argentina during the Early to Middle Miocene. Its taxonomic position is highly controversial, with authors alternatively considering it to be a cariamiform, typically a phorusrhacid or an anserimorph.
The Sophiornithidae are an extinct family of chicken-sized predatory birds that lived from the Paleocene to the Eocene periods of the Cenozoic, and were found primarily in Europe, and are thought to be primitive owls.
Mesembriornis is a genus of intermediate-sized phorusrhacids that grew up to 1.5 metres (4.9 ft) in height. They represent a well-distinct lineage of terror birds, differing from the massive large groups and the smaller Psilopterinae. In general proportions, they most resembled the Patagornithinae which flourished somewhat earlier, mainly to the south of the range of Mesembriornis. Fossils of the terror bird have been found in Montehermosan deposits of the Monte Hermoso Formation, as well as the Andalgala Formation and Chapadmalal Formation in Argentina.
Scalabrinitherium is an extinct genus of mammals of the family Macraucheniidae. Fossils of this animal were found among the fossils of prehistoric xenarthrans in the Ituzaingó Formation of Argentina.
Paraphysornis is an extinct genus of giant flightless terror birds that inhabited Brazil during Late Oligocene or Early Miocene epochs. Although not the tallest phorusrhacid, Paraphysornis was a notably robust bird, having short and robust tarsal bones not suited for pursuit hunting.
Kelenken is a genus of phorusrhacid, an extinct group of large, predatory birds, which lived in what is now Argentina in the middle Miocene about 15 million years ago. The only known specimen was discovered by high school student Guillermo Aguirre-Zabala in Comallo, in the region of Patagonia, and was made the holotype of the new genus and species Kelenken guillermoi in 2007. The genus name references a spirit in Tehuelche mythology, and the specific name honors the discoverer. The holotype consists of one of the most complete skulls known of a large phorusrhacid, as well as a tarsometatarsus lower leg bone and a phalanx toe bone. The discovery of Kelenken clarified the anatomy of large phorusrhacids, as these were previously much less well known. The closest living relatives of the phorusrhacids are the seriemas. Kelenken was found to belong in the subfamily Phorusrhacinae, along with for example Devincenzia.
Physornis is an extinct genus of giant flightless predatory birds of the family Phorusrhacidae or "terror birds", most closely related to Paraphysornis, that lived in Argentina. The type species is P. fortis. It lived during the Middle to Late Oligocene (Deseadan). Few fossils are known, but the available material suggests that Physornis was one of the largest phorusrhacids.
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 Formation to Early Pliocene (Montehermosan) of Argentina. The type species D. pozzi was formerly known as Onactornis pozzi. It stood about 2.5 metres (8.2 ft) tall, making it one of the largest Phorusrhacids and carnivorous birds known.
Patagornis is a genus of extinct flightless predatory birds of the family Phorusrhacidae. Known as "terror birds", these lived in what is now Argentina during the Early and Middle Miocene; the Santa Cruz Formation in Patagonia contains numerous specimens. Patagornis was an agile, medium sized Patagornithine and was likely a pursuit predator.
Andrewsornis is an extinct genus of giant flightless predatory birds of the family Phorusrhacidae or "terror birds" that lived in Oligocene Argentina. Fossils have been found in the Sarmiento Formation, and possibly the Agua de la Piedra Formation.
Procariama is an extinct monotypic genus of phorusrhacid, which lived from the Late Miocene to the Late Pliocene of Argentina. Fossils of the animal have been found in six places, in the Cerro Azul and Andalhuala Formations. More specifically in the Andagalá department and in the north of the Belén department of the Catamarca province, with a single location in the La Pampa province. The type and only species, Procariama simplex, is the largest member of the subfamily Psilopterinae.
Psilopterus is an extinct genus of phorusrhacid from the Middle Oligocene to possibly the Late Pleistocene of Argentina and Uruguay. Compared to other phorusrhacids, members of the genus are both relatively gracile and diminutive, and include the smallest known species of terror bird: with the head raised P. bachmanni was 70–80 centimeters (2.3–2.6 ft) in height and weighed about 5 kilograms (11 lb), while the largest members of the genus were only about 8 kilograms (18 lb). The birds resemble the modern cariama, except with a heavier build and considerably smaller wings. The strong morphological similarity between the claws of the predatory cariama and Psilopterus, both of which are sharp, curved, and laterally compressed, may indicate they were used to strike prey. Tonni and Tambussi also suggested that, in contrast to the other, larger terror birds, Psilopterus could use their claws to climb trees, and could even fly, but this has been rejected in more recent literature. Fossil finds in Uruguay indicate the genus may have survived until 96,040 ± 6,300 years ago, millions of years after the larger phorusrhacids became extinct.
Cariamiformes 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 Ameghinornithidae. Though traditionally considered a suborder within Gruiformes, both morphological and genetic studies show that it belongs to a separate group of birds, Australaves, whose other living members are Falconidae, Psittaciformes and Passeriformes.
Llallawavis scagliai is a large, extinct predatory bird from Pliocene Argentina. Its fossil is the most complete fossil of a phorusrhacid yet found.
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 terrestrial, long-legged predators, some of which attained massive sizes.
Dryornis, also called the Argentinian vulture, is an extinct genus of cathartid, known from Argentina. The genus contains two species, D. pampeanus and D. hatcheri.