Paracrax | |
---|---|
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Cariamiformes (?) |
Family: | Bathornithidae (?) |
Genus: | † Paracrax Pierce Brodkorb 1964 |
Type species | |
†Paracrax antiqua Brodkorb 1964 | |
Species | |
| |
Synonyms | |
|
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 instead, [1] or possibly entirely out of Cariamiformes [2] ), it is a specialised member of this group, being cursorial carnivores much like their South American cousins, some species attaining massive sizes.
Paracrax antiqua is the genus type species. [3] The type specimen, YPM 537, was collected in Weld County, Colorado, in 1871 by Othniel Charles Marsh, which identified it as a sort of turkey. [4] It was posteriorly referred to Cracidae by Pierce Brodkorb, [5] before its identity as a bathornithid came to light. [6] Material previously identified as a cormorant, "Phalacrocorax/Oligocrocorax" mediterraneus, was posteriorly identified as P. antiqua remains. [6]
Since then, two more species have been identified: P. wetmorei and P. gigantea. These were more closely related to each other than to P. antiqua. [6]
Most specimens have been found on the Brule Formation of North Dakota. Dating to the Rupelian stage of the Oligocene, it is composed of river deposits that showcase the remains of a rich savanna-like environment. Several large sized mammal groups are known from this region, such as rhinoceri, oreodonts and hyaenodonts, all co-existing with several flightless bathornithids. Bathornis , a possible close relative of Paracrax, appears to have favoured wetter ecosystems, while Paracrax occurs in drier environments. [3]
Paracrax is known from a variety of materials, such as pelvises, keels, forelimb elements and coracoids. The humerus material is distinct from the closely related Bathornis by an internal condyle that is less distinctively raised in relation to the external condyle. Overall, it can be assumed that it had similar proportions to phorusrhacids, with proportionally short wings and a large, deep bill. [6]
The keel is rather proportionally shallow, like a ratite's. It has unique characteristics quite unlike the sternum of any other bird (though vaguely convergent to that of the modern hoatzin), making it easily identifiable. [6] Both P. antiqua and P. gigantea were clearly flightless, being large birds with far too short forelimbs and keels, the former in particular having highly reduced metacarpals, though P. wetmorei might have still been capable of limited flight. [7]
Paracrax gigantea in particular is a very large bird, reaching estimated heights of over 2 m (6 ft 7 in), making it among the largest of bathornithids and among the tallest animals in its environment. [3] [6]
Like most Cariamiformes, including other bathornithids, Paracrax was likely a terrestrial carnivore. In terms of ecology, it would probably have been similar to its more famous relatives, the phorusrhacid terror birds, being a large, flightless killer and using its large axe-like beak to subdue and kill its prey. It is a prime example of a large flightless predator co-existing with large predatory mammals, such as the conspecific Hyaenodon , Dinictis , and Archaeotherium with which it probably shared an apex-predator role in its environment. [3] [6]
Grebes are aquatic diving birds in the order Podicipediformes. Grebes are widely distributed birds of freshwater, with some species also occurring in marine habitats during migration and winter. The order contains a single family, the Podicipedidae, which includes 22 species in six extant genera.
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".
Gastornis is an extinct genus of large flightless birds that lived during the late Paleocene and Eocene epochs of the Cenozoic era. The genus is currently thought to contain three or four distinct species, known from incomplete fossil remains, found in western-central Europe. More complete specimens are known from a fourth, North American species, which had previously been classified in the distinct genus Diatryma. Many scientists now consider Diatryma to be so similar to the other species of Gastornis that it should also be included in that genus. A fifth species, also previously classified in its own genus, is known from China.
Phorusrhacids, colloquially known as terror birds, are an extinct clade of large carnivorous flightless birds that were the largest species of apex predators in South America during the Cenozoic era; their conventionally accepted temporal range covers from 62 to 1.8 million years (Ma) ago.
The adzebills, genus Aptornis, were two closely related bird species, the North Island adzebill, Aptornis otidiformis, and the South Island adzebill, Aptornis defossor, of the extinct family Aptornithidae. The family was endemic to New Zealand. A fossil species, Aptornis proasciarostratus, is known from the Miocene Saint Bathans fauna.
Titanis is an extinct genus of giant flightless terror birds that inhabited North America during the early Pliocene to early Pleistocene epochs. The generic name, Titanis, refers to the titans, Ancient Greek gods that preceded the Twelve Olympians, in allusion to the bird's size. The specific name, T. walleri, honors the holotype's collector, Benjamin I. Waller, an avocational underwater archaeologist. Titanis was thought to be carnivorous and most likely preyed on the many small mammals of the time period. This giant flightless bird was one of the most efficient predators of its time in North America.
Strigogyps is an extinct genus of prehistoric bird from the Middle Eocene to Early Oligocene of France and Germany. It was probably around the size of a large chicken or a guan, weighing not quite 1 kilogram (2.2 lb). Apparently, as indicated by the ratio of lengths of wing to leg bones, S. sapea was flightless. Its legs were not adapted to running, so it seems to have had a walking lifestyle similar to trumpeters. Unlike other Cariamiformes, which appear to have been mostly carnivorous, Strigogyps specimens suggest a herbivorous diet.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1971.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1969.
Cunampaia is a dubious genus of extinct mesoeucrocodylian. Fossils have been found from the Divisadero Largo Formation of Mendoza Province, Argentina, and date back to the Divisaderan to Tinguirirican regional South American Land Mammal Age of the Late Eocene epoch.
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.
Australaves is a recently defined clade of birds, consisting of the Eufalconimorphae as well as the Cariamiformes. They appear to be the sister group of Afroaves. As in the case of Afroaves, the most basal clades have predatory extant members, suggesting this was the ancestral lifestyle; however, some researchers like Darren Naish are skeptical of this assessment, since some extinct representatives such as the herbivorous Strigogyps led other lifestyles. Basal parrots and falcons are at any rate vaguely crow-like and probably omnivorous.
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.
Eutreptornis is a genus of extinct possible cariamiforme bird from the Late Eocene of Utah. It is traditionally considered to be a bathornithid, though a combination of the relative incompleteness of the material alongside some differences from other bathornithids have raised some suspicions about this affiliation.
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.
Geranoididae is a clade of extinct gruiform birds from the early to late Eocene and possibly early Oligocene of North America and Europe. These were mid-sized, long-legged flightless birds, superficially similar but unrelated to modern ratites. However, a recent study shows that these birds may actually be palaeognaths related to ostriches.
Palaeophasianus is an extinct genus of flightless Geranoididae birds that lived in North America during the Eocene period. Robert Wilson Shufeldt classified Palaeophasianus as a galliform when he described it in 1913. However it was transferred to Cracidae in 1964 by Pierce Brodkorb, while Joel Cracraft in 1968 placed it in Gruiformes.