Presbyornithids
Fossil range: Late Cretaceous - Oligocene | | | Conservation status | | | | Scientific classification | | | | Genera | | see text Geography of the US in the late Cretaceous Late Cretaceous (also called the Upper Cretaceous) refers to the second half of the Cretaceous period, named after the famous white chalk cliffs of southern England, which date from this time. ...
The Oligocene epoch is a geologic period of time that extends from about 34 million to 23 million years before the present. ...
The conservation status of a species is an indicator of the likelihood of that species continuing to survive either in the present day or the future. ...
Three small ammonite fossils, each approximately 1. ...
Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. ...
Digimon, the only known animals. ...
Typical Classes See below Chordates (phylum Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates. ...
“Aves†redirects here. ...
Families Anhimidae Anseranatidae Anatidae †Dromornithidae †Presbyornithidae The order Anseriformes contains about 150 species of birds in three families: the Anhimidae (the screamers), Anseranatidae (the Magpie-goose), and the Anatidae, which includes over 140 species of waterfowl, among them the ducks, geese, and swans. ...
Frank Alexander Wetmore (June 18, 1886 _ December 7, 1978) was an American ornithologist and avian paleontologist. ...
Year 1926 (MCMXXVI) was a common year starting on Friday (link will display the full calendar). ...
For other uses of the word, please see Genus (disambiguation). ...
| Presbyornithidae were a family of waterbirds with an apparently global distribution that lived until the Earliest Oligocene, but are now extinct. Initially, they were believed to present a mix of characters shown by waterbirds, shorebirds and flamingos and were used to argue for an evolutionary relationship between these groups (Feduccia 1976), but they are now generally accepted to be "wading ducks", the sister taxon of the Anatidae, and thus essentially modern waterbirds. They were generally long-legged, long-necked birds, standing around 1 meter high, with the body of a duck, feet similar to a wader but webbed, and a flat ducklike bill adapted for filter feeding. Apparently, at least some species were very social birds that lived in large flocks and nested in colonies. In biological classification, family (Latin: familia, plural familiae) is 1) a rank or 2) a taxon in that rank. ...
Falcated Duck at Slimbridge Wildfowl and Wetlands centre, Gloucestershire, England Wildfowl or waterfowl, also waterbirds, is the collective term for the approximately 147 species of swans, geese and ducks, classified in the order Anseriformes, family Anatidae. ...
The Oligocene epoch is a geologic period of time that extends from about 34 million to 23 million years before the present. ...
In biology and ecology, extinction is the ceasing of existence of a species or group of species. ...
Families Charadridae Jacanidae Rostratulidae Ibidorhynchidae Recurvirostridae Haematopodidae Scolopacidae Dromadidae Burhinidae Glareolidae Thinocoridae Waders, called Shorebirds in North America (where wader is used to refer to long-legged wading birds such as storks and herons), are members of the order Charadriiformes, excluding the more marine web-footed seabird groups. ...
Flamingos are gregarious wading birds in the genus Phoenicopterus and family Phoenicopteridae. ...
This cladogram shows the relationship among various insect groups. ...
Subfamilies Dendrocygninae Thalassorninae Anserinae Stictonettinae Plectropterinae Tadorninae Anatinae Aythyinae Merginae Oxyurinae and see text Anatidae is the biological family that includes the ducks and most duck-like waterfowl, such as geese and swan. ...
Families Scolopacidae Rostratulidae Jacanidae Thinocoridae Pedionomidae Burhinidae Chionididae Pluvianellidae Ibidorhynchidae Recurvirostridae Haematopodidae Charadriidae Dunlin (Calidris alpina). ...
Filter feeders (also known as suspension feeders) are animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized structure, such as the baleen of baleen whales. ...
As the "wading duck" moniker implies, they were waterfowl whose elongated legs enabled them to live a lifestyle similar to the "proto-flamingos" (e.g. Palaelodus) - which were not really ancestors of the modern flamingos, but a group that evolved in parallel with them and in fact seems to have taken over part of the presbyornithid's ecological niche after the latter became extinct. Thus, while probably somewhat capable of swimming, they would have preferred to strain the shallow waters of their habitat for food and were also able to snatch up insects and small crustaceans on dry land, just like some species of modern ducks, e.g. the Laysan Duck, hunt for brine flies. Species (type) (disputed) (disputed) (disputed) (disputed) Synonyms Probalearica Lambrecht, 1933 Paloelodus (lapsus) Palaeolodus (lapsus) Palaelodus is an extinct genus of birds distantly related to flamingos. ...
Two lichenes species on a rock, in two different ecological niches In ecology, a niche is a term describing the relational position of a species or population in an ecosystem. ...
Orders See taxonomy Insects (Class Insecta) are a major group of arthropods and the most diverse group of animals on the Earth, with over a million described species—more than all other animal groups combined. ...
Classes & Subclasses Branchiopoda Phyllopoda Sarsostraca Remipedia Cephalocarida Maxillopoda Thecostraca Tantulocarida Branchiura Pentastomida Mystacocarida Copepoda Ostracoda Myodocopa Podocopa Malacostraca Phyllocarida Hoplocarida Eumalacostraca The crustaceans (Crustacea) are a large group of arthropods, comprising approximately 52,000 described species [1], and are usually treated as a subphylum [2].They include various familiar animals...
Binomial name Anas laysanensis Rothschild, 1892 The Laysan Duck, Anas laysanensis, is a dabbling duck which is endemic to Laysan Island, Hawaii. ...
Significance in avian evolution The implication of the plethora of this and other, ecologically similar Neornithes (e.g. the wastebasket taxon "Graculavidae") from the Late Cretaceous and early Palaeogene is that shore habitats offered most resources for ancestors of modern birds. The reasons seem to have been that arboreal niches were where the main radiation of the Enantiornithes had taken place some time earlier, and later on because the C-T mass extinction affected both aquatic and terrestrial habitats extensively, leading to the almost total collapse of their trophic webs. In marine habitats, the climatic changes associated with the mass extinction's cause(s) caused a wholesale die-off of oceanic phytoplankton and thus their food webs were destroyed from the bottom up. In terrestrial habitats on the other hand, apart from the loss of the primary production capacity, the keystone species, which were in almost all cases dinosaurs, disappeared, leading the trophic webs on dry land to collapse also from the inside out. Wastebin taxon (also called a wastebasket, or dustbin taxon) is a term used in taxonomic circles that refers to a taxon that has the sole purpose of classifying organisms that dont fit anywhere else. ...
Geography of the US in the late Cretaceous Late Cretaceous (also called the Upper Cretaceous) refers to the second half of the Cretaceous period, named after the famous white chalk cliffs of southern England, which date from this time. ...
Palaeogene (alternatively Paleogene) period is a unit of geologic time that began 65 and ended 23 million years ago. ...
This article is about the biological organisms known as trees. ...
The Enantiornithes, or opposite birds (because their foot bones are fused differently than in modern birds), are an extinct group of flying birds. ...
Badlands near Drumheller, Alberta where erosion has exposed the KT boundary. ...
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Diagrams of some typical phytoplankton Phytoplankton are the autotrophic component of the plankton that drift in the water column. ...
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Orders & Suborders Saurischia Sauropodomorpha Theropoda Ornithischia Thyreophora Ornithopoda Marginocephalia Dinosaurs were vertebrate animals that dominated the terrestrial ecosystem for over 160 million years, first appearing approximately 230 million years ago. ...
Specialized taxa of the older bird radiations that were very well adapted to their particular ecological niche and dependent on the intactness of the trophic webs had generally no chance to survive such mass extinctions. It is now apparent that at least the main evolutionary lineages of modern bird families already existed at the end of the Cretaceous, albeit they were somewhat marginal compared to the dominant, earlier groups of birds such as Enantiornithes and Confuciornithidae. This serves to show that in evolution the possession of derived or "modern" characters can actually be a disadvantage when a species needs to compete against well-established but more "primitive" lineages, especially as it must be understood that "primitive" refers only to descendence from a lineage that had been established a longer time ago, not that these species were any more generalist or less well-adapted than "modern" forms. In fact, that there were "no" (probably rather: very few) arboreal Neornithes by the end of the Cretaceous is today believed to be because the "primitive" Enantiornithes had had more time to develop adaptations to an arboreal lifestyle and were actually able to outcompete the "modern" arboreal forms, leaving vacant only a few possibilities for early Neornithes to evolve an arboreal lifestyle. The Cretaceous Period is one of the major divisions of the geologic timescale, reaching from the end of the Jurassic Period (i. ...
The Enantiornithes, or opposite birds (because their foot bones are fused differently than in modern birds), are an extinct group of flying birds. ...
This article is about evolution in biology. ...
This cladogram shows the relationship among various insect groups. ...
A generalist species is able to thrive in a wide variety of environmental conditions, and if a heterotroph, has a varied diet. ...
Orders Many - see section below. ...
At any rate and their evolutionary relationships nonwithstanding, most bird taxa that survived the mass extinction seem to have been living in environments where they could utilize both terrestrial as well as marine or limnic food resources (the ancestors of the Galliformes probably being the one noteworthy exception). Until the trophic webs had diversified and become complex enough again, such generalist forms were at a competitive advantage. When specialization became a feasible evolutionary strategy again, however, they were outcompeted by more advanced taxa. Note that here, too, "generalist" does not imply that these birds were competitively inferior in their entire ecological niche, only that whenever some form evolves specialization for living in part of this niche, the generalis is at a competitive disadvantage in that particular part of its niche. As time progresses and consequently opportunities for specialization accumulate, it may happen that the generalis forms are either forced to specialize themselves to maintain a competitive edge, or disappear, their niche being in effect divided up by specialist forms. Families Megapodidae Numididae Odontophoridae Phasianidae Meleagrididae Tetraonidae Cracidae Mesitornithidae The Galliformes is an order of birds containing the turkeys, grouse, quails and pheasants. ...
Principles in evolution as demonstrated by the Presbyornithidae
- Generalist forms which have more "fall-back" potential if part of an ecological niche gets destroyed are better adapted to survive mass extinctions than specialized forms which occupy a narrow ecological niche.
- Primitiveness in descent does not translate into "primitiveness" in morphology or adaptation. The former is an absolute value defined by when the lineage in question separated from relatives which later underwent additional radiation. The latter is dependent on when the last mass extinction created opportunities for the survivors to embark on a new adaptive journey.
- After a lineage has been able to evolve uninterrupted for a considerable amount of time, there is a trend for generalists to be competitively excluded from more and more of their niche(s) by specialist forms, both related and unrelated, that by and by adapt to particular parts of the generalist's niche.
- With continuing uninterrupted evolution of a lineage, remaining plesiomorphies are usually non-adaptive: Presbyornis was a bird which, although primitive by descent and generalist by ecology, was uniquely and highly adapted to its particular mode of life, in a way that is not found anymore in modern waterfowl, because the ecological niche to which it was most well adapted was later partitioned away for the most part, with other opportunities for generalist forms arising in the process.
This cladogram shows the relationship among various insect groups. ...
Systematics Four genera are unequivocally accepted to belong to the Presbyornithidae: For other uses of the word, please see Genus (disambiguation). ...
There is one species generally accepted in Headonornis, Vegavis and Telmabates each. Presbyornis contains 2 or 3 described species. Vegavis is known from the Late Cretaceous of Antarctica, whereas Telmabates lived in today's Patagonia during the Eocene. The genus Nautilornis is today considered a synonym of Presbyornis, which is found in a wide range of Late Paleocene to Early Oligocene deposits in North America and Europe. Additionally, most of the bones referred to Headonornis have been found to belong to Presbyornis, and the remaining coracoid may do so too (Dyke, 2001). In zoological nomenclature, a type is a specimen or a taxon. ...
Vegavis is a recently discovered genus of extinct birds that lived during the Cretaceous period. ...
Geography of the US in the late Cretaceous Late Cretaceous (also called the Upper Cretaceous) refers to the second half of the Cretaceous period, named after the famous white chalk cliffs of southern England, which date from this time. ...
In orange the area most commonly defined as Patagonia. ...
The Eocene epoch (55. ...
In zoological nomenclature, synonyms are different scientific names that pertain to the same taxon, for example two names for the same species. ...
The Paleocene, early dawn of the recent, is a geologic epoch that lasted from 65. ...
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In human beings, the coracoid process is a small hook-like structure that comes off the scapula to point forward. ...
Apart from these unequivocal presbyornithids, there are some genera which are tentatively assigned to this family pending the discovery of more complete material. As many fossils from the Early Palaeogene show somewhat ambiguous characters, it is not easy to place these early modern birds unequivocally into one lineage or another. That they were ecologically generalized and are usually known from very few fossil remains only serves to worsen this situation. Three small ammonite fossils, each approximately 1. ...
Possible genera of presbyornithids include:
- Teviornis
- Proherodius
- Zhylgaia
of which the first is known from Late Cretaceous deposits in Mongolia, the second latter from the Early Eocene of England, and the third is an enigmatic Late Cretaceous or Paleogene form from Central Asia. There are some other, undescribed, presbyornithid or possible presbyornithid remains, such as the partial right scapula BMNH PAL 4989, which was considered part of Headonornis hantoniensis, but cannot be positively refererred to a known taxon, or the Early Cretaceous remains from the Mongolian Barun Goyot Formation at Uday Sayr and the Nemegt Formation of Tsagaan Kushu. Motto: (French for God and my right) Anthem: God Save the King/Queen Capital London (de facto) Largest city London Official language(s) English (de facto) Unification - by Athelstan AD 927 Area - Total 130,395 km² (1st in UK) 50,346 sq mi Population - 2006 est. ...
Paleogene (alternatively Palaeogene) period is a unit of geologic time that began 65 and ended 23 million years ago. ...
Map of Central Asia showing three sets of possible boundaries for the region Central Asia located as a region of the world Central Asia is a vast landlocked region of Asia. ...
Left scapula - front view () Left scapula - rear view () In anatomy, the scapula, or shoulder blade, is the bone that connects the humerus (arm bone) with the clavicle (collar bone). ...
For other similarly-named museums see Museum of Natural History. ...
The Barun Goyot Formation is located within and is widely represented in the Gobi Desert basin of Mongolia. ...
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See also - Galloanserae
- Hesperornithes for a basal ("ancient") lineage of early modern birds that contained what were probably the most derived ("advanced") birds ever to live.
Orders Galliformes Anseriformes Fowl is a term for certain birds often used as food by humans. ...
Families Enaliornithidae Baptornithidae Hesperornithidae Synonyms Odontornithes Marsh, 1873 (partim) Odontolcae Marsh, 1875 Gaviomorphae Cracraft, 1982 (partim) Hesperornithes are an extinct and highly specialized subclass of Cretaceous toothed birds. ...
In phylogenetics, basal members of a group are subgroups that diverged very early from the others. ...
References - Dyke, Gareth J. (2001): The Fossil Waterfowl (Aves: Anseriformes) from the Eocene of England. American Museum Novitates 3354: 1-15. PDF fulltext
- Feduccia, Alan (1976): Osteological evidence for shorebird affinities of the flamingos. Auk 93(3): 587-601. PDF fulltext
- Wetmore, Alexander (1926): Fossil birds from the Green River Deposits of Easter Utah. Annals of the Carnegie Museum 16: 391-402.
The Auk is a quarterly journal and the official publication of the American Ornithologists Union, having been continuously published by that body since 1884. ...
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