The darters, anhingas, or snakebirds are mainly tropical waterbirds in the family Anhingidae, which contains a single genus, Anhinga. There are four living species, three of which are very common and widespread while the fourth is rarer and classified as near-threatened by the IUCN. The term snakebird is usually used without any additions to signify whichever of the completely allopatric species occurs in any one region. It refers to their long thin neck, which has a snake-like appearance when they swim with their bodies submerged, or when mated pairs twist it during their bonding displays. "Darter" is used with a geographical term when referring to particular species. It alludes to their manner of procuring food, as they impale fishes with their thin, pointed beak. The American darter is more commonly known as the anhinga. It is sometimes called "water turkey" in the southern United States; though the anhinga is quite unrelated to the wild turkey, they are both large, blackish birds with long tails that are sometimes hunted for food.
The Gruiformes are an order containing a considerable number of living and extinct bird families, with a widespread geographical diversity. Gruiform means "crane-like".
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".
The mousebirds are birds in the order Coliiformes. They are the sister group to the clade Cavitaves, which includes the Leptosomiformes, Trogoniformes (trogons), Bucerotiformes, Piciformes and Coraciformes. This group is now confined to sub-Saharan Africa, and it is the only bird order confined entirely to that continent, with the possible exception of turacos which are considered by some as the distinct order Musophagiformes, and the cuckoo roller, which is the only member of the order Leptosomiformes, and which is found in Madagascar but not mainland Africa. Mousebirds had a wider range in the Paleogene, with a widespread distribution in Europe and North America during the Paleocene.
Phorusrhacids, colloquially known as terror birds, are an extinct family of large carnivorous, mostly flightless birds that were among the largest apex predators in South America during the Cenozoic era. Their definitive fossil records range from the Middle Eocene to the Late Pleistocene around 43 to 0.1 million years ago, though some specimens suggest that they were present since the Early Eocene.
Megapaloelodus is an extinct genus of stem flamingo of the family Palaelodidae. Megapaloelodus is primarily known from Miocene America, from South Dakota and Oregon in the north to Argentina in the south, but the species Megapaloelodus goliath was found in Europe. Additionally, one unnamed species was discovered in Miocene sediments from Namibia. Due to a lack of skull material, little can be said about the ecology of Megapaloelodus. Species of this genus are typically larger than those of Palaelodus and appear to have inhabited similar brackish lake environments. Additionally, they may have been capable of "locking" their legs in a standing position.
The red-legged seriema, also known as the crested cariama and crested seriema, is a mostly predatory terrestrial bird in the seriema family (Cariamidae), included in the Gruiformes in the old polyphyletic circumscription but recently placed in a distinct order: Cariamiformes.
The black-legged seriema is one of two living species of seriemas in the family Cariamidae. It is found from southeastern Bolivia and northern Paraguay south into north-central Argentina. It is a large, mostly grey bird with a long neck, a long tail, and long, slender black legs. Its belly, vent and thighs are yellowish-white. The sexes look similar, as do immature birds, though the latter are more patterned on head, neck and back. First described for science by Gustav Hartlaub in 1860, it is monotypic, with no subspecies. Like its red-legged cousin, it is an omnivore. It seldom flies, instead pursuing prey and eluding danger on foot. Its loud calls, said to sound like kookaburras, turkeys or yelping dogs, are often given in duet. Little is known about its breeding ecology. It is known to breed in November and December, building a platform nest of sticks and laying two white eggs, which are sometimes marked with a few brownish or purple spots. The International Union for Conservation of Nature rates the species as one of least concern, due to its large range and apparently stable numbers.
The Santacrucian age is a period of geologic time within the Early Miocene epoch of the Neogene, used more specifically with SALMA classification in South America. It follows the Colhuehuapian and precedes the Friasian age.
The order Falconiformes is represented by the extant family Falconidae and a handful of enigmatic Paleogene species. Traditionally, the other bird of prey families Cathartidae, Sagittariidae (secretarybird), Pandionidae (ospreys), Accipitridae (hawks) were classified in Falconiformes. A variety of comparative genome analyses published since 2008, however, found that falcons are part of a clade of birds called Australaves, which also includes seriemas, parrots and passerines. Within Australaves falcons are more closely related to the parrot-passerine clade than they are to the seriemas. The hawks, vultures and owls are placed in the clade Afroaves.
Cariamiformes is an order of primarily flightless birds that has existed for over 50 million years. The group includes the family Cariamidae (seriemas) and the extinct families such as Phorusrhacidae, Bathornithidae, Idiornithidae and Ameghinornithidae. Extant members (seriemas) are only known from South America, but fossils of many extinct taxa are also found in other continents including Europe and North America. 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.
Chunga is one of two known genera of seriemas in the family Cariamidae. It is found in Argentina, Bolivia, and Paraguay. It contains one living species, the black-legged seriema. A prehistoric species, Chunga incerta, has been described from the Miocene and Pliocene Monte Hermoso Formation of Argentina.
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 extinct Phorusrhacidae. They were likely similar in habits, being terrestrial, long-legged predators, some of which attained massive sizes.
Paracrax is a genus of extinct North American flightless birds, possibly related to modern seriemas and the extinct terror birds. Part of Bathornithidae, it is a specialised member of this group, being cursorial carnivores much like their South American cousins, some species attaining massive sizes.
Bathornis is an extinct lineage of birds related to modern day seriemas, that lived in North America about 37–20 million years ago. Like the closely related and also extinct phorusrhacids, it was a flightless predator, occupying predatory niches in environments classically considered to be dominated by mammals. It was a highly diverse and successful genus, spanning a large number of species that occurred from the Priabonian Eocene to the Burdigalian Miocene epochs.
Elaphrocnemus is a genus of extinct bird from the Eocene and Oligocene periods of Europe. Part of Cariamiformes, its closest living relatives are seriemas, though it differs significantly from them, being a better flyer.
Thegornis is an extinct genus of herpetotherine falconid that lived during the Miocene of South America. The genus was erected by Florentino Ameghino in 1895 based on two species, T. musculosus and T. debilis. However, T. debilis was later suggested to be an invalid species, with the differences between it and T. musculosus being due to sexual dimorphism. Two additional species, T. spivacowi and T. sosae, were subsequently named in later years by Federico Agnolín. Its skull and postcranial morphology are similar to the laughing falcon and forest falcon, which together form the clade Herpetotherinae. The seriema Noriegavis's holotype was transferred to this genus and the well-preserved specimen described in 2015 attributed to Noriegavis has been classified into Miocariama.
The Santa Cruz Formation is a geological formation in the Magallanes/Austral Basin in southern Patagonia in Argentina and adjacent areas of Chile. It dates to the late Early Miocene epoch, and is contemporaneous with the eponymous Santacrucian age of the SALMA timescale. The Santa Cruz Formation is known for its abundance of vertebrate fossils, including South American native ungulates, as well as rodents, xenarthrans, and metatherians.
Cariama santacrucensis is an extinct species of seriema, which lived during the Early Miocene. The holotype specimen is MPM-PV 3511; the fossil is an incomplete skull from the Puesto Estancia La Costa fossil formation in Southern Santa Cruz Province, Argentina.
