The herons are long-legged freshwater and coastal birds in the family Ardeidae, with 64 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genera Botaurus and Ixobrychus are referred to as bitterns, together with the zigzag heron, or zigzag bittern, in the monotypic genus Zebrilus, form a monophyletic group within the Ardeidae. Egrets are not a biologically distinct group from the herons, tend to be named differently because they are white or have decorative plumes in breeding plumage. Herons, by evolutionary adaptation, have long beaks; the classification of the individual heron/egret species is fraught with difficulty, no clear consensus exists about the correct placement of many species into either of the two major genera and Egretta. The relationships of the genera in the family are not resolved. However, one species considered to constitute a separate monotypic family, the Cochlearidae or the boat-billed heron, is now regarded as a member of the Ardeidae.
Although herons resemble birds in some other families, such as the storks, ibises and cranes, they differ from these in flying with their necks retracted, not outstretched. They are one of the bird groups that have powder down; some members of this group nest colonially in trees, while others, notably the bitterns, use reed beds. The herons are medium - to large-sized birds with long necks, they exhibit little sexual dimorphism in size. The smallest species is considered the little bittern, which can measure under 30 cm in length, although all the species in the genus Ixobrychus are small and many broadly overlap in size; the largest species of heron is the goliath heron. The necks are able to kink in an S-shape, due to the modified shape of the cervical vertebrae, of which they have 20–21; the neck is able to retract and extend, is retracted during flight, unlike most other long-necked birds. The neck is longer in the day herons than the night bitterns; the legs are long and strong and in every species are unfeathered from the lower part of the tibia.
In flight, the legs and feet are held backward. The feet of herons have thin toes, with three forward-pointing ones and one pointing backward; the bill is long and harpoon-like. It can vary from fine, as in the agami heron, to thick as in the grey heron; the most atypical bill is owned by the boat-billed heron, which has a thick bill. The bill, as well as other bare parts of the body, is yellow, black, or brown in colour, although this can vary during the breeding season; the wings are broad and long, exhibiting 10 or 11 primary feathers, 15–20 secondaries. and 12 rectrices. The feathers of the herons are soft and the plumage is blue, brown, grey, or white, can be strikingly complex. Amongst the day herons, little sexual dimorphism in plumage is seen. Many species have different colour morphs. In the Pacific reef heron, both dark and light colour morphs exist, the percentage of each morph varies geographically. White morphs only occur in areas with coral beaches; the herons are a widespread family with a cosmopolitan distribution.
They exist on all continents except Antarctica, are present in most habitats except the coldest extremes of the Arctic high mountains, the driest deserts. All species are associated with water, they are predominantly found in lowland areas, although some species live in alpine areas, the majority of species occurs in the tropics. The herons are a mobile family, with most species being at least migratory; some species are migratory, for example the grey heron, sedentary in Britain, but migratory in Scandinavia. Birds are inclined to disperse after breeding, but before the annual migration, where the species is colonial, searching out new feeding areas and reducing the pressures on feeding grounds near the colony; the migration occurs at night as individuals or in small groups. The herons and bitterns are carnivorous; the members of this family are associated with wetlands and water, feed on a variety of live aquatic prey. Their diet includes a wide variety of aquatic animals, including fish, amphibians, crustaceans and aquatic insects.
Individual species may be generalists or specialise in certain prey types, such as the yellow-crowned night heron, which specialises in crustaceans crabs. Many species opportunistically take larger prey, including birds and bird eggs and more carrion. More herons eating acorns and grains have been reported, but most vegetable matter consumed is accidental; the most common hunting technique is for the bird to sit motionless on the edge of or standing in shallow water and to wait until prey comes within range. Birds may either do this from an upright posture, giving them a wider field of view for seeing prey, or from a crouched position, more cryptic and means the bill is closer to the prey when it is located. Having seen prey, the head is moved from side to side, so that the heron can calculate the position of the prey in the water and compensate for refraction, the bill is used to spear the prey. In addition to sitting and waiting, herons may feed more actively, they may walk around or l
Binomial nomenclature called binominal nomenclature or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. Such a name is called a binomen, binominal name or a scientific name; the first part of the name – the generic name – identifies the genus to which the species belongs, while the second part – the specific name or specific epithet – identifies the species within the genus. For example, humans belong within this genus to the species Homo sapiens. Tyrannosaurus rex is the most known binomial; the formal introduction of this system of naming species is credited to Carl Linnaeus beginning with his work Species Plantarum in 1753. But Gaspard Bauhin, in as early as 1623, had introduced in his book Pinax theatri botanici many names of genera that were adopted by Linnaeus; the application of binomial nomenclature is now governed by various internationally agreed codes of rules, of which the two most important are the International Code of Zoological Nomenclature for animals and the International Code of Nomenclature for algae and plants.
Although the general principles underlying binomial nomenclature are common to these two codes, there are some differences, both in the terminology they use and in their precise rules. In modern usage, the first letter of the first part of the name, the genus, is always capitalized in writing, while that of the second part is not when derived from a proper noun such as the name of a person or place. Both parts are italicized when a binomial name occurs in normal text, thus the binomial name of the annual phlox is now written as Phlox drummondii. In scientific works, the authority for a binomial name is given, at least when it is first mentioned, the date of publication may be specified. In zoology "Patella vulgata Linnaeus, 1758"; the name "Linnaeus" tells the reader who it was that first published a description and name for this species of limpet. "Passer domesticus". The original name given by Linnaeus was Fringilla domestica; the ICZN does not require that the name of the person who changed the genus be given, nor the date on which the change was made, although nomenclatorial catalogs include such information.
In botany "Amaranthus retroflexus L." – "L." is the standard abbreviation used in botany for "Linnaeus". "Hyacinthoides italica Rothm. – Linnaeus first named this bluebell species Scilla italica. The name is composed of two word-forming elements: "bi", a Latin prefix for two, "-nomial", relating to a term or terms; the word "binomium" was used in Medieval Latin to mean a two-term expression in mathematics. Prior to the adoption of the modern binomial system of naming species, a scientific name consisted of a generic name combined with a specific name, from one to several words long. Together they formed a system of polynomial nomenclature; these names had two separate functions. First, to designate or label the species, second, to be a diagnosis or description. In a simple genus, containing only two species, it was easy to tell them apart with a one-word genus and a one-word specific name; such "polynomial names" may sometimes look like binomials, but are different. For example, Gerard's herbal describes various kinds of spiderwort: "The first is called Phalangium ramosum, Branched Spiderwort.
The other... is aptly termed Phalangium Ephemerum Virginianum, Soon-Fading Spiderwort of Virginia". The Latin phrases are short descriptions, rather than identifying labels; the Bauhins, in particular Caspar Bauhin, took some important steps towards the binomial system, by pruning the Latin descriptions, in many cases to two words. The adoption by biologists of a system of binomial nomenclature is due to Swedish botanist and physician Carl von Linné, more known by his Latinized name Carl Linnaeus, it was in his 1753 Species Plantarum that he first began using a one-word "trivial name" together with a generic name in a system of binomial nomenclature. This trivial name is what is now known as specific name; the Bauhins' genus names were retained in many of these, but the descriptive part was reduced to a single word. Linnaeus's trivial names introduced an important new idea, namely that the function of a name could be to give a species a unique label; this meant. Thus Gerard's Phalangium ephemerum virginianum became Tradescantia virgi
Australia the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania and numerous smaller islands. It is the world's sixth-largest country by total area; the neighbouring countries are Papua New Guinea and East Timor to the north. The population of 25 million is urbanised and concentrated on the eastern seaboard. Australia's capital is Canberra, its largest city is Sydney; the country's other major metropolitan areas are Melbourne, Brisbane and Adelaide. Australia was inhabited by indigenous Australians for about 60,000 years before the first British settlement in the late 18th century, it is documented. After the European exploration of the continent by Dutch explorers in 1606, who named it New Holland, Australia's eastern half was claimed by Great Britain in 1770 and settled through penal transportation to the colony of New South Wales from 26 January 1788, a date which became Australia's national day; the population grew in subsequent decades, by the 1850s most of the continent had been explored and an additional five self-governing crown colonies established.
On 1 January 1901, the six colonies federated. Australia has since maintained a stable liberal democratic political system that functions as a federal parliamentary constitutional monarchy, comprising six states and ten territories. Being the oldest and driest inhabited continent, with the least fertile soils, Australia has a landmass of 7,617,930 square kilometres. A megadiverse country, its size gives it a wide variety of landscapes, with deserts in the centre, tropical rainforests in the north-east and mountain ranges in the south-east. A gold rush began in Australia in the early 1850s, its population density, 2.8 inhabitants per square kilometre, remains among the lowest in the world. Australia generates its income from various sources including mining-related exports, telecommunications and manufacturing. Indigenous Australian rock art is the oldest and richest in the world, dating as far back as 60,000 years and spread across hundreds of thousands of sites. Australia is a developed country, with the world's 14th-largest economy.
It has a high-income economy, with the world's tenth-highest per capita income. It is a regional power, has the world's 13th-highest military expenditure. Australia has the world's ninth-largest immigrant population, with immigrants accounting for 26% of the population. Having the third-highest human development index and the eighth-highest ranked democracy globally, the country ranks in quality of life, education, economic freedom, civil liberties and political rights, with all its major cities faring well in global comparative livability surveys. Australia is a member of the United Nations, G20, Commonwealth of Nations, ANZUS, Organisation for Economic Co-operation and Development, World Trade Organization, Asia-Pacific Economic Cooperation, Pacific Islands Forum and the ASEAN Plus Six mechanism; the name Australia is derived from the Latin Terra Australis, a name used for a hypothetical continent in the Southern Hemisphere since ancient times. When Europeans first began visiting and mapping Australia in the 17th century, the name Terra Australis was applied to the new territories.
Until the early 19th century, Australia was best known as "New Holland", a name first applied by the Dutch explorer Abel Tasman in 1644 and subsequently anglicised. Terra Australis still saw occasional usage, such as in scientific texts; the name Australia was popularised by the explorer Matthew Flinders, who said it was "more agreeable to the ear, an assimilation to the names of the other great portions of the earth". The first time that Australia appears to have been used was in April 1817, when Governor Lachlan Macquarie acknowledged the receipt of Flinders' charts of Australia from Lord Bathurst. In December 1817, Macquarie recommended to the Colonial Office. In 1824, the Admiralty agreed that the continent should be known by that name; the first official published use of the new name came with the publication in 1830 of The Australia Directory by the Hydrographic Office. Colloquial names for Australia include "Oz" and "the Land Down Under". Other epithets include "the Great Southern Land", "the Lucky Country", "the Sunburnt Country", "the Wide Brown Land".
The latter two both derive from Dorothea Mackellar's 1908 poem "My Country". Human habitation of the Australian continent is estimated to have begun around 65,000 to 70,000 years ago, with the migration of people by land bridges and short sea-crossings from what is now Southeast Asia; these first inhabitants were the ancestors of modern Indigenous Australians. Aboriginal Australian culture is one of the oldest continual civilisations on earth. At the time of first European contact, most Indigenous Australians were hunter-gatherers with complex economies and societies. Recent archaeological finds suggest. Indigenous Australians have an oral culture with spiritual values based on reverence for the land and a belief in the Dreamtime; the Torres Strait Islanders, ethnically Melanesian, obtained their livelihood from seasonal horticulture and the resources of their reefs and seas. The northern coasts and waters of Australia were visited s
A chordate is an animal constituting the phylum Chordata. During some period of their life cycle, chordates possess a notochord, a dorsal nerve cord, pharyngeal slits, an endostyle, a post-anal tail: these five anatomical features define this phylum. Chordates are bilaterally symmetric; the Chordata and Ambulacraria together form the superphylum Deuterostomia. Chordates are divided into three subphyla: Vertebrata. There are extinct taxa such as the Vetulicolia. Hemichordata has been presented as a fourth chordate subphylum, but now is treated as a separate phylum: hemichordates and Echinodermata form the Ambulacraria, the sister phylum of the Chordates. Of the more than 65,000 living species of chordates, about half are bony fish that are members of the superclass Osteichthyes. Chordate fossils have been found from as early as the Cambrian explosion, 541 million years ago. Cladistically, vertebrates - chordates with the notochord replaced by a vertebral column during development - are considered to be a subgroup of the clade Craniata, which consists of chordates with a skull.
The Craniata and Tunicata compose the clade Olfactores. Chordates form a phylum of animals that are defined by having at some stage in their lives all of the following anatomical features: A notochord, a stiff rod of cartilage that extends along the inside of the body. Among the vertebrate sub-group of chordates the notochord develops into the spine, in wholly aquatic species this helps the animal to swim by flexing its tail. A dorsal neural tube. In fish and other vertebrates, this develops into the spinal cord, the main communications trunk of the nervous system. Pharyngeal slits; the pharynx is the part of the throat behind the mouth. In fish, the slits are modified to form gills, but in some other chordates they are part of a filter-feeding system that extracts particles of food from the water in which the animals live. Post-anal tail. A muscular tail that extends backwards behind the anus. An endostyle; this is a groove in the ventral wall of the pharynx. In filter-feeding species it produces mucus to gather food particles, which helps in transporting food to the esophagus.
It stores iodine, may be a precursor of the vertebrate thyroid gland. There are soft constraints that separate chordates from certain other biological lineages, but are not part of the formal definition: All chordates are deuterostomes; this means. All chordates are based on a bilateral body plan. All chordates are coelomates, have a fluid filled body cavity called a coelom with a complete lining called peritoneum derived from mesoderm; the following schema is from the third edition of Vertebrate Palaeontology. The invertebrate chordate classes are from Fishes of the World. While it is structured so as to reflect evolutionary relationships, it retains the traditional ranks used in Linnaean taxonomy. Phylum Chordata †Vetulicolia? Subphylum Cephalochordata – Class Leptocardii Clade Olfactores Subphylum Tunicata – Class Ascidiacea Class Thaliacea Class Appendicularia Class Sorberacea Subphylum Vertebrata Infraphylum incertae sedis Cyclostomata Superclass'Agnatha' paraphyletic Class Myxini Class Petromyzontida or Hyperoartia Class †Conodonta Class †Myllokunmingiida Class †Pteraspidomorphi Class †Thelodonti Class †Anaspida Class †Cephalaspidomorphi Infraphylum Gnathostomata Class †Placodermi Class Chondrichthyes Class †Acanthodii Superclass Osteichthyes Class Actinopterygii Class Sarcopterygii Superclass Tetrapoda Class Amphibia Class Sauropsida Class Synapsida Craniates, one of the three subdivisions of chordates, all have distinct skulls.
They include the hagfish. Michael J. Benton commented that "craniates are characterized by their heads, just as chordates, or all deuterostomes, are by their tails". Most craniates are vertebrates; these consist of a series of bony or cartilaginous cylindrical vertebrae with neural arches that protect the spinal cord, with projections that link the vertebrae. However hagfish have incomplete braincases and no vertebrae, are therefore not regarded as vertebrates, but as members of the craniates, the group from which vertebrates are thought to have evolved; however the cladistic exclusion of hagfish from the vertebrates is controversial, as they ma
Johann Friedrich Gmelin
Johann Friedrich Gmelin was a German naturalist, entomologist and malacologist. Johann Friedrich Gmelin was born as the eldest son of Philipp Friedrich Gmelin in 1748 in Tübingen, he studied medicine under his father at University of Tübingen and graduated with an MD in 1768, with a thesis entitled: Irritabilitatem vegetabilium, in singulis plantarum partibus exploratam ulterioribusque experimentis confirmatam. Defended under the presidency of Ferdinand Christoph Oetinger, whom he thanks with the words Patrono et praeceptore in aeternum pie devenerando, pro summis in medicina obtinendis honoribus. In 1769, Gmelin became an adjunct professor of medicine at University of Tübingen. In 1773, he became professor of philosophy and adjunct professor of medicine at University of Göttingen, he was promoted to full professor of medicine and professor of chemistry and mineralogy in 1778. He died in 1804 in Göttingen. Johann Friedrich Gmelin published several textbooks in the fields of chemistry, pharmaceutical science and botany.
He published the 13th edition of Systema Naturae by Carl Linnaeus in 1788 and 1789. This contained descriptions and scientific names of many new species, including birds that had earlier been catalogued without a scientific name by John Latham in his A General Synopsis of Birds. Gmelin's publication is cited as the authority for over 290 bird species and a number of butterfly species. Among his students were Georg Friedrich Hildebrandt, Carl Friedrich Kielmeyer, Friedrich Stromeyer, Wilhelm August Lampadius, he was the father of Leopold Gmelin. He described the redfin pickerel in 1789. In the scientific field of herpetology, he described many new species of reptiles. In the field of malacology, he named many species of gastropods; the abbreviation "Gmel." is found. Gmelin, Johann Friedrich. Irritabilitatem vegetabilium, in singulis plantarum partibus exploratam ulterioribusque experimentis confirmatam. Thesis Tübingen. OCLC 10717434. Allgemeine Geschichte der Gifte, 2 Vol. 1776/77 Digital edition of the University and State Library Düsseldorf.
Allgemeine Geschichte der Pflanzengifte, 1777 Allgemeine Geschichte der mineralischen Gifte. Nürnberg: Raspe, 1777. Digital edition of the University and State Library Düsseldorf. Johann Friedrich Gmelins... Einleitung in die Chemie zum Gebrauch auf Universitäten. Nürnberg: Raspe, 1780. Digital edition of the University and State Library Düsseldorf. Einleitung in die Pharmacie. Nürnberg: Raspe, 1781. Digital edition of the University and State Library Düsseldorf. Beyträge zur Geschichte des teutschen Bergbaus, 1783 Ueber die neuere Entdeckungen in der Lehre von der Luft, und deren Anwendung auf Arzneikunst, in Briefen an einen Arzt, von J. F. Gmelin. 1784 Grundsätze der technischen Chemie, 1786 Caroli a Linné, equitis aurati de stella polari, … Systema naturae per regna tria naturae, secundum classes, genera, cum characteribus, synonymis, locis. Editio decima tertia, reformata. Lipsiae, Georg Emanuel Beer, 1789-1790 Grundriß der Pharmazie, 1792 Apparatus Medicaminum tam simplicium quam praeparatorum et compositorum in Praxeos Adiumentum consideratus, Ps.
2, T. 1 - Ps. 2, T. 2. 1795–1796. Digital edition of the University and State Library Düsseldorf. Geschichte der Chemie, 1799 Allgemeine Geschichte der thierischen und mineralischen Gifte, 1806 Vane-Wright, R. I. 1975. The butterflies named by J. F. Gmelin. Bulletin of the British Museum,Entomology, 32: 17-64.pdf Gmelin's chemical genealogy Johann Friedrich Gmelin at the Mathematics Genealogy Project Johann Friedrich Gmelin in the German National Library catalogue "Author Details for Johann Friedrich Gmelin". International Plant Names Index. International Organization for Plant Information. Books by Johann Friedrich Gmelin at Internet Archive Zoologica Göttingen State and University Library
Tasmania is an island state of Australia. It is located 240 km to the south of the Australian mainland, separated by Bass Strait; the state encompasses the main island of Tasmania, the 26th-largest island in the world, the surrounding 334 islands. The state has a population of around 526,700 as of March 2018. Just over forty percent of the population resides in the Greater Hobart precinct, which forms the metropolitan area of the state capital and largest city, Hobart. Tasmania's area is 68,401 km2, of which the main island covers 64,519 km2, it is promoted as a natural state, protected areas of Tasmania cover about 42% of its land area, which includes national parks and World Heritage Sites. Tasmania was the founding place of the first environmental political party in the world; the island is believed to have been occupied by indigenous peoples for 30,000 years before British colonisation. It is thought Aboriginal Tasmanians were separated from the mainland Aboriginal groups about 10,000 years ago when the sea rose to form Bass Strait.
The Aboriginal population is estimated to have been between 3,000 and 7,000 at the time of colonisation, but was wiped out within 30 years by a combination of violent guerrilla conflict with settlers known as the "Black War", intertribal conflict, from the late 1820s, the spread of infectious diseases to which they had no immunity. The conflict, which peaked between 1825 and 1831, led to more than three years of martial law, cost the lives of 1,100 Aboriginals and settlers; the island was permanently settled by Europeans in 1803 as a penal settlement of the British Empire to prevent claims to the land by the First French Empire during the Napoleonic Wars. The island was part of the Colony of New South Wales but became a separate, self-governing colony under the name Van Diemen's Land in 1825. 75,000 convicts were sent to Van Diemen's Land before transportation ceased in 1853. In 1854 the present Constitution of Tasmania was passed, the following year the colony received permission to change its name to Tasmania.
In 1901 it became a state through the process of the Federation of Australia. The state is named after Dutch explorer Abel Tasman, who made the first reported European sighting of the island on 24 November 1642. Tasman named the island Anthony van Diemen's Land after his sponsor Anthony van Diemen, the Governor of the Dutch East Indies; the name was shortened to Van Diemen's Land by the British. It was renamed Tasmania in honour of its first European discoverer on 1 January 1856. Tasmania was sometimes referred to as "Dervon," as mentioned in the Jerilderie Letter written by the notorious Australian bushranger Ned Kelly in 1879; the colloquial expression for the state is "Tassie". Tasmania is colloquially shortened to "Tas," when used in business names and website addresses. TAS is the Australia Post abbreviation for the state; the reconstructed Palawa kani language name for Tasmania is Lutriwita. The island was adjoined to the mainland of Australia until the end of the last glacial period about 10,000 years ago.
Much of the island is composed of Jurassic dolerite intrusions through other rock types, sometimes forming large columnar joints. Tasmania has the world's largest areas of dolerite, with many distinctive mountains and cliffs formed from this rock type; the central plateau and the southeast portions of the island are dolerites. Mount Wellington above Hobart is a good example. In the southern midlands as far south as Hobart, the dolerite is underlaid by sandstone and similar sedimentary stones. In the southwest, Precambrian quartzites were formed from ancient sea sediments and form strikingly sharp ridges and ranges, such as Federation Peak or Frenchmans Cap. In the northeast and east, continental granites can be seen, such as at Freycinet, similar to coastal granites on mainland Australia. In the northwest and west, mineral-rich volcanic rock can be seen at Mount Read near Rosebery, or at Mount Lyell near Queenstown. Present in the south and northwest is limestone with caves; the quartzite and dolerite areas in the higher mountains show evidence of glaciation, much of Australia's glaciated landscape is found on the Central Plateau and the Southwest.
Cradle Mountain, another dolerite peak, for example, was a nunatak. The combination of these different rock types contributes to scenery, distinct from any other region of the world. In the far southwest corner of the state, the geology is wholly quartzite, which gives the mountains the false impression of having snow-capped peaks year round. Evidence indicates the presence of Aborigines in Tasmania about 42,000 years ago. Rising sea levels cut Tasmania off from mainland Australia about 10,000 years ago and by the time of European contact, the Aboriginal people in Tasmania had nine major nations or ethnic groups. At the time of the British occupation and colonisation in 1803, the indigenous population was estimated at between 3,000 and 10,000. Historian Lyndall Ryan's analysis of population studies led her to conclude that there were about 7,000 spread throughout the island's nine nations. J. B. Plomley and Rhys Jones, settled on a figure of 3,000 to 4,000, they engaged in fire-stick farming, hunted game including kangaroo and wallabies, caught seals, mutton-birds and fish and lived as nine separate "nations" on the island, which they knew as "Trouwunna".
The first reported sighting of Tasmania by a European was on 24 November 1642 by Dutch explorer Abel Tasman, who landed at today's Blackman Bay. More than a century in 1772, a French expedition le
The Pelecaniformes are an order of medium-sized and large waterbirds found worldwide. As traditionally—but erroneously—defined, they encompass all birds that have feet with all four toes webbed. Hence, they were also known by such names as totipalmates or steganopodes. Most have a bare throat patch, the nostrils have evolved into dysfunctional slits, forcing them to breathe through their mouths, they feed on squid, or similar marine life. Nesting is colonial; the young are altricial, hatching from the egg naked in most. They lack a brood patch; the Fregatidae, Phalacrocoracidae and Phaethontidae were traditionally placed in the Pelecaniformes, but molecular and morphological studies indicate they are not such close relatives. They have been placed in their own orders and Phaethontiformes, respectively. Classically, bird relationships were based on morphological characteristics; the Pelecaniformes were traditionally—but erroneously—defined as birds that have feet with all four toes webbed, as opposed to all other birds with webbed feet where only three of four were webbed.
Hence, they were also known by such names as totipalmates or steganopodes. The group included frigatebirds, cormorants and tropicbirds. Sibley and Ahlquist's landmark DNA-DNA hybridisation studies led to them placing the families traditionally contained within the Pelecaniformes together with the grebes, cormorants and spoonbills, New World vultures, penguins, albatrosses and loons together as a subgroup within a expanded order Ciconiiformes, a radical move which by now has been all but rejected: their "Ciconiiformes" assembled all early advanced land- and seabirds for which their research technique delivered insufficient phylogenetic resolution. Morphological study has suggested pelicans are sister to a gannet-cormorant clade, yet genetic analysis groups them with the hamerkop and shoebill, though the exact relationship between the three is unclear. Mounting evidence pointed to the shoebill as a close relative of pelicans; this included microscopic analysis of eggshell structure by Konstantin Mikhailov in 1995, who found that the shells of pelecaniform eggs were covered in a thick microglobular material.
Reviewing genetic evidence to date and colleagues surmised that pelicans were sister to the shoebill with the hamerkop as the next earlier offshoot. Ericson and colleagues sampled five nuclear genes in a 2006 study spanning the breadth of bird lineages, came up with pelicans and hamerkop in a clade. Hackett and colleagues sampled 32 kilobases of nuclear DNA and recovered shoebill and hamerkop as sister taxa, pelicans sister to them, herons and ibises as sister groups to each other with this heron and ibis group a sister to the pelican/shoebill/hamerkop clade; the current International Ornithological Committee classification has pelicans grouped with the shoebill, hamerkop and spoonbills, herons and bitterns. Recent research suggests that the similarities between the Pelecaniformes as traditionally defined are the result of convergent evolution rather than common descent, that the group is paraphyletic. All families in the traditional or revised Pelecaniformes except the Phalacrocoracidae have only a few handfuls of species at most, but many were more numerous in the Early Neogene.
Fossil genera and species are discussed in genus accounts. This is "Sula" ronzoni from Early Oligocene rocks at Ronzon, believed to be a sea-duck and is an ancestral Pelecaniform; the pelecaniform lineages appear to have originated around the end of the Cretaceous. Monophyletic or not, they appear to belong to a close-knit group of "higher waterbirds" which includes groups such as penguins and Procellariiformes. Quite a lot of fossil bones from around the Cretaceous–Paleogene boundary cannot be placed with any of these orders and rather combine traits of several of them; this is, of course, only to be expected, if the theory that most if not all of these "higher waterbird" lineages originated around that time is correct. Of those basal taxa, the following show some similarities to the traditional Pelecaniformes: Lonchodytes Torotix Tytthostonyx Cladornis "Liptornis"—a nomen dubiumThe proposed Elopterygidae—supposedly a family of Cretaceous Pelecaniformes—are neither monophyletic nor does Elopteryx appear to be a modern bird.
Pelecaniformes portal Bourdon, Estelle. J. Vertebr. Paleontol. 25: 157–170. DOI: 10.1671/0272-46340252.0. CO. Journal für Ornithologie 144: 157–175. HTML abstract Mortimer, Michael: The Theropod Database: Phylogeny of taxa. Retrieved 2013-MAR-02. Tree of Life: Pelecaniformes