| Geranoididae Temporal range: Eocene | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Infraclass: | Palaeognathae |
| Family: | † Geranoididae Wetmore, 1933 |
| Genera | |
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Geranoididae is a clade of extinct birds from the early to late Eocene and possibly early Oligocene of North America and Europe. These were mid-sized, long-legged flightless birds. [1] [2] [3] [4] [5] Recent research shows that these birds may actually be palaeognaths related to ostriches. [6]
It is rather unambiguous that geranoidids are either part of or stem representatives of Gruoidea, the clade that includes modern cranes, limpkins and trumpeters, though their precise relationship varies among studies, some recovering them as sister taxa to another clade of flightless ratite-like birds, the eogruiids. The most recent consensus appears to be that geranoidids are outside of Gruoidea, with eogruiids being more closely related to modern cranes. [4] However, Mayr (2019) argued that close affinities between Geranoididae and the palaeognathous family Palaeotididae are at least as well supported as the classification of geranoidids into the Gruiformes. [6]
The exact number of genera and species are also somewhat controversial. For instance, a recent study recovers Geranoides as possibly synonymous with Palaeophasianus and Eogeranoides as possibly synonymous with Paragrus . [4]
Most geranoidids appear to have been flightless, with long legs and short wings, and presumably with herbivorous habits, giving them a profile and lifestyle similar to that of modern ratites. Most if not all of them were forest dwellers, a lifestyle also present in contemporaneous ratites such as Palaeotis and Remiornis . [7] While competition and lack thereof between ratites and eogruiids has been examined extensively, [8] [9] [10] niche partitioning between geranoidids and ratites has currently not, in spite of factors like geranoidids being most common in North America, where there are no ratites, or the fact that some European ratites were carnivorous. [5] [11]
Geranoidids are most common in Eocene fossil sites in North America, particularly in the Willwood Formation were up to six species are known. Galligeranoides occurs in the Eocene of France in association with another flightless bird, Gastornis , potentially indicating that geranoidids took advantage of land bridges to arrive to Europe. [3] However, Mayr (2019) considered Galligeranoides to be a member of Palaeognathae closely related to Palaeotis , and formally transferred Galligeranoides from the family Geranoididae to the family Palaeotididae. This transfer restricts the fossil record of the family Geranoididae to North America. [6]
Struthioniformes is an order of birds with only a single extant family, Struthionidae, containing the ostriches. Several other extinct families are known, spanning across the Northern Hemisphere, from the Early Eocene to the early Pliocene, including a variety of flightless forms like the Paleotididae, Geranoididae, Eogruidae and Ergilornithidae, the latter two thought to be closely related to Struthionidae.
A ratite is any of a diverse group of flightless, large, long-necked, and long-legged birds of the infraclass Palaeognathae. Kiwi, the exception, are much smaller and shorter-legged and are the only nocturnal extant ratites.
The Gruiformes are an order containing a considerable number of living and extinct bird families, with a widespread geographical diversity. Gruiform means "crane-like".
Struthionidae is a family of flightless birds, containing the extant ostriches and their extinct relatives. The two extant species of ostrich are the common ostrich and Somali ostrich, both in the genus Struthio, which also contains several species known from Holocene fossils such as the Asian ostrich. The common ostrich is the more widespread of the two living species, and is the largest living bird species. The extinct genus Pachystruthio from the Late Pliocene-Early Pleistocene of Eurasia is one of the largest birds ever.
The adzebills, genus Aptornis, were two closely related bird species, the North Island adzebill,, and the South Island adzebill,, of the extinct family Aptornithidae. The family was endemic to New Zealand. A fossil species,, is known from the Miocene Saint Bathans fauna.
Palaeognathae is a infraclass of birds, called paleognaths, within the class Aves of the clade Archosauria. It is one of the two extant infraclasses of birds, the other being Neognathae, both of which form Neornithes. Palaeognathae contains five extant branches of flightless lineages, termed ratites, and one flying lineage, the Neotropic tinamous. There are 47 species of tinamous, five of kiwis (Apteryx), three of cassowaries (Casuarius), one of emus (Dromaius), two of rheas (Rhea) and two of ostrich (Struthio). Recent research has indicated that paleognaths are monophyletic but the traditional taxonomic split between flightless and flighted forms is incorrect; tinamous are within the ratite radiation, meaning flightlessness arose independently multiple times via parallel evolution.
Palaeotis is a genus of paleognath birds from the middle Eocene epoch of central Europe. One species is known, Palaeotis weigelti. The holotype specimen is a fossil tarsometatarsus and phalanx. Lambrect (1928) described it as an extinct bustard, and gave it its consequent name. After a suggestion by Storrs L. Olson, a review of the type specimen and the referral of several other fossils by Houde and Haubold (1987) concluded that Palaeotis is a palaeognath and assigned it to the same order as ostriches; the Struthioniformes. In 2021, it was considered a member of the family Paleotididae alongside Galligeranoides from the Early Eocene of France, which were found to be basal members of the Struthioniformes.
Macrodontopteryx is a genus of the prehistoric pseudotooth birds of somewhat doubtful validity. These animals were probably rather close relatives of either pelicans and storks, or of waterfowl, and are here placed in the order Odontopterygiformes to account for this uncertainty.
Lithornis is a genus of extinct paleognathous birds. Although Lithornis was able to fly well, their closest relatives are the extant tinamous and ratites.
Lithornithidae is an extinct, possibly paraphyletic group of early paleognath birds. They are known from fossils dating to the Upper Paleocene through the Middle Eocene of North America and Europe, with possible Late Cretaceous representatives. All are extinct today; the youngest specimen is the currently unnamed SGPIMH MEV1 specimen from the mid-Eocene Messel Pit site.
Remiornis heberti is an extinct species of paleognath bird from the Paleocene of France. It is a species comparable in size to modern rheas, and possibly related to another European Paleogene ratite, Palaeotis. In spite of being one of the oldest ratites in the world, it is often ignored for Gondwana vicariance narratives.
Gruimorphae is a clade of birds that contains the orders Charadriiformes and Gruiformes identified by molecular analysis. This grouping has had historical support, as various charadriiform families such as the families Pedionomidae and Turnicidae were classified as gruiforms. It may also have support from the fossil record since the discovery of Nahmavis from the Early Eocene of North America.
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.
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.
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.
Eogruidae is a family of large, flightless birds that inhabited Asia from the Eocene to Pliocene epochs. Related to modern ostriches, it was formerly thought to be related to cranes, limpkins and trumpeters and that the similarities with ostriches were due to similar speciations to cursoriality, with both groups showing reduced numbers of toes to two in some taxa. It has been suggested that competition from true ostriches has caused the extinction of these birds, though this has never been formally tested and several ostrich taxa do occur in the late Cenozoic of Asia and some species do occur in areas where ostrich fossils have also been found. It has been suggested that the family is paraphyetic, with Ergilornithidae more closely related to modern ostriches than to Eogrus or Sonogrus.
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.
Messelornithidae is an extinct clade of gruiform birds, closely related to modern rails. The fossil record are from the Paleocene to the early Oligocene of Europe and North America.
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