''Patagornis'' is a

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 ...

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 ...

flightless

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

s of the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

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 ...

. Known as "terror birds", these lived in what is now

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

during the Early and Middle Miocene; the

Santa Cruz Formation The Santa Cruz Formation is a geological formation in the Magallanes/Austral Basin in southern Patagonia in Argentina and in adjacent areas of Chile. It dates to the late Early Miocene epoch, and is contemporaneous with eponymous Santacrucian ...

Patagonia Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and gl ...

contains numerous specimens.''Patagornis''
at

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ...

.org ''Patagornis'' was an agile, medium sized Patagornithine and was likely a pursuit predator.

Etymology

The genus name means "bird from Patagonia" after the location the fossils were found in and the species name after prominent American paleontologist

Othniel Charles Marsh Othniel Charles Marsh (October 29, 1831 – March 18, 1899) was an American professor of Paleontology in Yale College and President of the National Academy of Sciences. He was one of the preeminent scientists in the field of paleontology. Among h ...

, who had also named notable fossil birds but from the American West like ''

Hesperornis ''Hesperornis'' (meaning "western bird") is a genus of cormorant-like bird that spanned the first half of the Campanian age of the Late Cretaceous period (83.5–78 mya). One of the lesser-known discoveries of the paleontologist O. C. Marsh i ...

'' and ''Ichthyornis''.Moreno, F. P., & Mercerat, A. (1891). ''Catálogo de los pájaros fósiles de la República Argentina conservados en el Museo de La Plata''. Taller de Publicaciones del Museo. Recently, Federico Agnolin has promoted reusing

Florentino Ameghino Florentino Ameghino (born Giovanni Battista Fiorino Giuseppe Ameghino September 19, 1853 – August 6, 1911) was an Argentine naturalist, paleontologist, anthropologist and zoologist, whose fossil discoveries on the Argentine Pampas, especially ...

’s 1891 name ''Tolmodus inflatus'' because the name ''Patagornis marshi'' wasn’t used for over 100 years until a paper by Alvarenga & Höfling in 2003.Agnolin, F. (2013). La posición sistemática de Hermosiornis (Aves, Phororhacoidea) y sus implicancias filogenéticas. ''Revista del Museo Argentino de Ciencias Naturales nueva serie'', ''15''(1), 39-60. This would make the name ''Patagornis marshi'' a ''

nomen nudum In taxonomy, a ''nomen nudum'' ('naked name'; plural ''nomina nuda'') is a designation which looks exactly like a scientific name of an organism, and may have originally been intended to be one, but it has not been published with an adequate descr ...

'' and ''Tolmodus inflatus'' the valid name due to its frequent use. Despite this, the use of the ''Patagornis marshi'' has had a great resurgence in use in recent years and the proper nomenclature hasn't been established by the

ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the I ...

. The generic name ''Tolmodus'' means "bold tooth" due to the misinterpretation of the holotype premaxilla as the tooth of a mammal, while the species name means "inflated" due to its large size.

History and taxonomy

In 1891 during the "Argentine Bone Wars", a competition between Argentine paleontologists

Francisco Moreno Francisco Pascasio Moreno (May 31, 1852 – November 22, 1919) was a prominent explorer and academic in Argentina, where he is usually referred to as ''Perito'' Moreno (''perito'' means "specialist, expert"). Perito Moreno has been credited as on ...

and

, the former and his colleague Alcides Mercerart described a new genus and species of phorusrhacid, ''Patagornis marshi'', based on a

mandibular symphysis In human anatomy, the facial skeleton of the skull the external surface of the mandible is marked in the median line by a faint ridge, indicating the mandibular symphysis (Latin: ''symphysis menti'') or line of junction where the two lateral halves ...

that was missing the tip, though it was then thought to be a piece of the

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has b ...

. The fossil ( MLP-143) was found alongside many other parts of a skeleton, likely from the same individual as the symphysis, including: 3 vertebrae and fragments of many others, parts of the hindlimbs, and ungues.Brodkorb, P. (1967). ''Catalogue of fossil birds: part 3 (Ralliformes, Ichthyornithiformes, Charadriiformes)''. University of Florida. The specific locality where these fossils were found isn't known in detail, besides that they came from the upper

middle Miocene The Middle Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene. The sub-epoch lasted from 15.97 ± 0.05 Ma to 11.608 ± 0.005 Ma (million y ...

strata of the Santa Cruz Formation of Santa Cruz, Argentina. In the same paper, Moreno and Mercerat named 2 more species of ''Patagornis, Patagornis lemoinei'' and ''Patagornis bachmanni,'' based on fossils found in the

Monte León Formation Monte may refer to: Places Argentina * Argentine Monte, an ecoregion * Monte Desert * Monte Partido, a ''partido'' in Buenos Aires Province Italy * Monte Bregagno * Monte Cassino * Montecorvino (disambiguation) * Montefalcione Portugal * Monte ...

, Argentina in

lower Miocene The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene Epoch made up of two stages: the Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 Ma to 15.97 ± 0.05 Ma (million years ago). It was prec ...

strata. They also named ''Palaeociconia cristata'' based on 2 vertebrae and 2 ungues from Santa Cruz, believing that they were from a fossil stork related to '' Ciconia.'' In 1933, biologist Karl Lambert placed ''P. cristata'' in its own genus, ''Morenomerceraria,'' but the genus name has since no use since. ''Palaeociconia cristata'' has since been synonymized with ''Patagornis marshi''. ''P. lemoinei'' and ''P. bachmanni'' are now species of ''Psilopterus.'' Moreno's rival, Ameghino, also unknowingly found or described many fossils of ''Patagornis marshi'' from the Miocene deposits in Santa Cruz, many of the fossils being collected by Ameghino's brother

Carlos Ameghino Carlos Ciriaco Ameghino (16 June 1865 – 12 April 1936) was an Argentine paleontologist and explorer who accompanied his brother Florentino Ameghino throughout Argentina searching for fossils. Scientific career Carlos Ameghino was educated ...

. In August of 1891, Ameghino named ''Tolmodus inflatus'' based on a fragment of the right premaxilla that had been collected by Carlos in the same middle Miocene deposits in Santa Cruz.Ameghino, F. (1891). "Mamíferos y aves fósiles argentinas. Especies nuevas, adiciones y correcciones". ''Revista Argentina de Historia Natural''. 1: 240–259. Ameghino originally considered the taxon an

edentate Xenarthra (; from Ancient Greek ξένος, xénos, "foreign, alien" + ἄρθρον, árthron, "joint") is a major clade of placental mammals native to the Americas. There are 31 living species: the anteaters, tree sloths, and armadillos. Ex ...

mammal related to ''

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 ...

'', but 2 months later in June he synonymized the two and realized that they were actually flightless carnivorous birds, a conclusion made earlier by Moreno. Ameghino over several years amassed many ''Patagornis'' fossils, many of which were described in his 1895 monograph on Patagonian fossil birds.Ameghino, F. (1895). Sur les oiseaux fossils de patagonie et le faune mammalogique des couches á Pyrotherium. Premiére contribution á la connissance de la faune mammalogique des couches á Pyrotherium. ''Boletín del Instituto Geografico Argentino'', ''15'', 603-660. The most complete skeleton ( BMNH-A516) includes a complete skull and mandible, one of the first complete Phorusrhacid skulls known, and many limb elements as well as a complete pelvis. Another synonym of ''Patagornis marshi'' was named by Ameghino in 1895, ''Phororhacos modicus,'' based on a humerus and tarsometatarsus from Santa Cruz and another mistakenly assigned fossil was a premaxilla wrongfully assigned by Ameghino to the rhea ''

Opisthodactylus ''Opisthodactylus'' is an extinct genus of rhea from the Early to Middle Miocene Santa Cruz and Chichinales Formations and the Late Miocene ( Montehermosan) Andalhuala Formation of Argentina. Three species are described: the type species, ''O ...

''. Ameghino also believed that the fossils came from the Cretaceous and Eocene "''

Pyrotherium ''Pyrotherium'' ('fire beast') is an extinct genus of South American ungulate, of the order Pyrotheria, that lived in what is now Argentina and Bolivia, during the Late Oligocene. By the end of the "Argentine Bone Wars", many ''Patagornis'' fossils had been collected and majority reside in the

Museo de la Plata The La Plata Museum ( es, Museo de la Plata) is a natural history museum in La Plata, Argentina. It is part of the (Natural Sciences School) of the UNLP (National University of La Plata). The building, long, today houses 3 million fossils an ...

or the

Natural History Museum, London The Natural History Museum in London is a museum that exhibits a vast range of specimens from various segments of natural history. It is one of three major museums on Exhibition Road in South Kensington, the others being the Science Museum an ...

. Several fragmentary ''Patagornis'' specimens were also collected by American crews from

Princeton University Princeton University is a private university, private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial Colleges, fourth-oldest ins ...

and the

Field Museum of Natural History The Field Museum of Natural History (FMNH), also known as The Field Museum, is a natural history museum in Chicago, Illinois, and is one of the largest such museums in the world. The museum is popular for the size and quality of its educational ...

Princeton Princeton University is a private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the ni ...

New Jersey New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware ...

and

Chicago (''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name ...

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolita ...

respectively, although the fossils found by the former now reside at the

American Museum of Natural History The American Museum of Natural History (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 inter ...

New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...

. The Museo de la Plata also collected a nearly complete ''Patagornis'' skeleton, including a skull, though it is poorly preserved.

Description and paleobiology

''Patagornis'' was very similar to ''Andalgalornis'', another member of the subfamily Patagornithinae, in size and weight, however '' Andalgalornis'' was slightly larger. The diameter of the leg bones was about 15% larger than in the living rhea. However, the back height was about the same at 90–100 cm. Estimates of the weight vary: 45 to 50 kgBlanco, R. Ernesto; Washington W. Jones
Terror birds on the run: a mechanical model to estimate its maximum running speed.
''Proceedings of the Royal Society'' 272 (no. 1574): 1769-1773 (september 2005). Geraadpleegd op 18 augustus 2012. or only 23 kg. The walking speed of birds is determined by the ratio of the two leg bones tibiotarsus and tarsometatarsus and by their strength. At ''Patagornis'' this ratio is almost 70%, meaning that the taxon was very agile, a trait common among the smaller Patagornithines. Research from 2005 therefore showed that the animal had a maximum speed of 50 km/h, about the same speed as the living rhea. The anterior margin of the fenestra antorbitalis of ''Patagornis'' is moderately sloped, while at ''

Andrewsornis ''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 ...

'' it is strongly sloping and at ''Andalgalornis'' only slightly sloping. Alvarenga & Hofling describe the dorsal portion of the nostrils as "very conspicuous". The symphysis mandibulae is slightly curved, with the apex of the beak end uncurved. On the best preserved ''Patagornis'' skeleton, BMNH-A516, the ulna preserved large quill knobs on the posterior end that suggest large wing feathers. These feathers were theorized to have been used for assistance in running, as implied by its ecology and limb anatomy, or as a shield like on the extant Secretary bird. The former theory is much more likely based on the anatomy of the quill knobs themselves and their presence in the related '' Llallawavis'' which has a similar agile anatomy. The ungual phalanges preserved in ''Patagornis'' and its distant relative ''Mesembriornis'' are large, curved, and thin laterally, likely being used to stab prey based on those of modern predatory birds.

Ear anatomy

In 2015 during their study on the ear anatomy of phorusrhacids, Degrange ''et al'' also studied the internal ear anatomy preserved in '' Llallawavis, Patagornis,'' & several modern birds. They discovered that the hearing of ''Patagornis'' was very poor & had the smallest hearing range in the

Cariamiformes 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 Ame ...

studied. The semicircular canals of ''Llallawavis'' were much more elongated compared to the short canals of ''Patagornis,'' and with the greater body mass, it was inferred that there were more sluggish head movements in this taxon, with enhanced sensitivity to low-amplitude motions.

Classification

Due to the great preservation of ''Patagornis'' and its relatives, comparisons with other taxa and detailed classification are much easier compared to other phorusrhacids. In 2003 during their redescription of phorusrhacidae, Herculano Alvarenga and Elizabeth Hofling created a new subfamily, Patagornithinae, with ''Patagornis'' as the type genus. ''Patagornis'' is similar to its relatives ''

'' and '' Andalgalornis'' in that they all are medium-sized phorusrhacids with slender, lightly built bodies, long and narrow mandibular symphyses, and long and slender tibiotarsi and tarsometatarsi. However, a phylogenetic analysis in 2015 by Degrange ''et al'' found ''Patagornis'' in a merged Phorusrhacinae and in polytomy with ''

Physornis ''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 Mi ...

'' and ''

'' as well. The following phylogenetic tree shows the internal relationships of Phorusrhacidae under the exclusion of ''Brontornis'' as published by Degrange and colleagues in 2015, which recovers ''Patagornis'' as a member of a large clade that includes ''Physornis'', ''Phorusrhacos'' and ''Andalgalornis'', among others.

Paleoenvironment

''Patagornis'' lived during the

in the Santa Cruz Formation, which preserves mostly a coastal environment, but also forested and grassland regions.Croft, D. A. (2016). ''Horned armadillos and rafting monkeys: the fascinating fossil mammals of South America''. Indiana University Press. The area had little rainfall, so forests developed around lakes and rivers, giving Santa Cruz a diverse environment. During the Miocene, the climate was similar to those of the coasts of

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

with semi-

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...

forests and oceanic winds. Grasslands began spreading into Argentina during the Miocene, though much of inner

was still arid with small rainforests in between.Townsend, K. B., & Croft, D. A. (2008). Diets of notoungulates from the Santa Cruz Formation, Argentina: new evidence from enamel microwear. ''Journal of Vertebrate Paleontology'', ''28''(1), 217-230. Large, herbivorous, South American

notoungulate Notoungulata is an extinct order of mammalian ungulates that inhabited South America from the early Paleocene to the Holocene, living from approximately 61 million to 11,000 years ago. Notoungulates were morphologically diverse, with forms resemb ...

mammals like the

Toxodonts Toxodontia. Retrieved April 2013. is a suborder of the meridiungulate order Notoungulata. Most of the members of the five included families, including the largest notoungulates, share several dental, auditory and tarsal specializations. The g ...

Nesodon ''Nesodon'' ("island tooth")Palmer (1904) p. 457. is a genus of Miocene mammal belonging to the extinct order Notoungulata which inhabited southern South America during the Late Oligocene to Miocene living from 29.0 to 16.3 Ma and existed fo ...

'' and '' Adinotherium'' were the large low browsers, with rabbit-like Interathere ''

Protypotherium ''Protypotherium'' is an extinct genus of notoungulate mammals native to South America during the Oligocene and Miocene epochs. A number of closely related animals date back further, to the Eocene. Fossils of ''Protypotherium'' have been found ...

'' being

frugivorous A frugivore is an animal that thrives mostly on raw fruits or succulent fruit-like produce of plants such as roots, shoots, nuts and seeds. Approximately 20% of mammalian herbivores eat fruit. Frugivores are highly dependent on the abundance and ...

. Both mammalian and avian carnivores inhabited the area, the largest being the Phorusrhacid ''

.''

Marsupials Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in a po ...

also lived in the region, including the large carnivorous

Sparassodont Sparassodonta (from Greek to tear, rend; and , gen. , ' tooth) is an extinct order of carnivorous metatherian mammals native to South America, related to modern marsupials. They were once considered to be true marsupials, but are now though ...

Borhyaena ''Borhyaena'' is an extinct genus of South American metatherian, living between 17.5 and 15.5 million years ago in Patagonia, Argentina ( Santa Cruz and Sarmiento Formations) and Chile ( Río Frias Formation). ''Patagornis'' is also known from the coastal Monte Leon Formation that was in the same region in Santa Cruz, but part of the older

age.Cuitiño, J. I., Fernicola, J. C., Raigemborn, M. S., & Krapovickas, V. (2019)
Stratigraphy and depositional environments of the Santa Cruz Formation (early–middle Miocene) along the Río Santa Cruz, southern Patagonia, Argentina.
''Publicación Electrónica de la Asociación Paleontológica Argentina'', ''19''(2). Monte Leon preserved more

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...

and

estuarine An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...

sediments, but with a very similar fauna to the Santa Cruz Formation as the two formations had a direct transition.

References

External links

Genus Taxonomy
{{Taxonbar, from=Q1866161 Phorusrhacidae Extinct flightless birds Miocene birds of South America Laventan Colloncuran Friasian Santacrucian Neogene Argentina Fossils of Argentina Fossil taxa described in 1891