Pelecaniformes

Life-forms

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Infraclassis: Archosauromorpha
Cladus: Crurotarsi
Divisio: Archosauria
Cladus: Avemetatarsalia
Cladus: Ornithodira
Subtaxon: Dinosauromorpha
Cladus: Dinosauriformes
Cladus: Dracohors
Cladus: Dinosauria
Ordo: Saurischia
Cladus: Eusaurischia
Subordo: Theropoda
Cladus: Neotheropoda
Cladus: Averostra
Cladus: Tetanurae
Cladus: Avetheropoda
Cladus: Coelurosauria
Cladus: Tyrannoraptora
Cladus: Maniraptoromorpha
Cladus: Maniraptoriformes
Cladus: Maniraptora
Cladus: Pennaraptora
Cladus: Paraves
Cladus: Eumaniraptora
Cladus: Avialae
Infraclassis: Aves
Cladus: Euavialae
Cladus: Avebrevicauda
Cladus: Pygostylia
Cladus: Ornithothoraces
Cladus: Ornithuromorpha
Cladus: Carinatae
Parvclassis: Neornithes
Cohors: Neognathae
Cladus: Neoaves
Cladus: Aequornithes
Ordo: Pelecaniformes

‎Infraclassis: Aves
Cohors: Neognathae
Cladus: Neoaves
Cladus: Aequornithes
Ordo: Pelecaniformes
Familiae: Ardeidae – Balaenicipitidae – Pelecanidae – Scopidae – Threskiornithidae – †Plotopteridae

Formerly included, now transferred to Suliformes: Anhingidae - Fregatidae - Phalacrocoracidae - Sulidae
Formerly included, now transferred to Phaethontiformes: Phaethontidae – †Prophaethontidae

Name

Pelecaniformes Sharpe, 1891: 76
References
Primary references

Sharpe, R.B. 1891. A review of recent attempts to classify birds; an address delivered before the Second International Ornithological Congress on the 18th of May, 1891. DOI: 10.5962/bhl.title.13335 BHL Reference page.

Additional references

Hackett, S.J. et al. 2008. A Phylogenomic Study of Birds Reveals Their Evolutionary History. Science 320: 1763–1768.
Jarvis, E.D. et al. 2014. Whole-genome analyses resolve early branches in the tree of life of modern birds. Science 346: 1320–1331.

Vernacular names
العربية: بجعيات
azərbaycanca: Qutankimilər
беларуская: Пеліканападобныя
català: Pelicaniforme
čeština: Veslonozí
dansk: Årefodede
Deutsch: Ruderfüßer
Esperanto: Pelikanoformaj
suomi: Pelikaanilinnut
Nordfriisk: Peelekaanfögler
galego: Pelicanos
עברית: שקנאים
hrvatski: Pelikanke
magyar: Gödényalakúak
íslenska: Pelíkanfuglar
日本語: ペリカン目
ქართული: ნიჩაბფეხიანები
한국어: 사다새목
lietuvių: Irklakojiniai paukščiai
latviešu: Pelikānveidīgie
македонски: Пеликановидни
Nederlands: Roeipotigen
norsk nynorsk: Pelikanfuglar
norsk: Pelikanfugler
polski: Pelikanowe
русский: Пеликанообразные
srpskohrvatski / српскохрватски: Pelikanke / Пеликанке
slovenčina: Pelikánotvaré
slovenščina: Veslonožci
српски / srpski: Весларице
svenska: Pelikanfåglar
ไทย: อันดับนกกระทุง
Türkçe: Pelikanlar
українська: Пеліканоподібні
Tiếng Việt: Bộ Bồ nông
Zeêuws: Pelekaonachtegen
中文: 鹈形目

The Pelecaniformes /pɛlɪˈkænɪfɔːrmiːz/ 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 formerly also known by such names as totipalmates or steganopodes. Most have a bare throat patch (gular patch), and the nostrils have evolved into dysfunctional slits, forcing them to breathe through their mouths. They also have a pectinate nail on their longest toe. This is shaped like a comb and is used to brush out and separate their feathers. They feed on fish, squid, or similar marine life. Nesting is colonial, but individual birds are monogamous. The young are altricial, hatching from the egg helpless and naked in most. They lack a brood patch.

The pelicans, shoebill and hamerkop form a clade within the order, with their next closest relatives being a clade containing the herons, ibises and spoonbills. The Fregatidae (frigatebirds), Sulidae (gannets and boobies), Phalacrocoracidae (cormorants and shags), Anhingidae (darters), and Phaethontidae (tropicbirds) 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, Suliformes and Phaethontiformes, respectively.[3]

Systematics and evolution

Classically, bird relationships were based solely on morphological characteristics. The Pelecaniformes were traditionally, but erroneously, defined as birds that have feet with all four toes webbed (totipalmate), as opposed to all other birds with webbed feet where only three of four were webbed. Hence, they were formerly also known by such names as totipalmates or steganopodes. The group included frigatebirds, gannets, cormorants, anhingas, and tropicbirds.[4]

Sibley and Ahlquist's landmark DNA-DNA hybridisation studies (see Sibley-Ahlquist taxonomy) led to them placing the families traditionally contained within the Pelecaniformes together with the grebes, cormorants, ibises and spoonbills, New World vultures, storks, penguins, albatrosses, petrels, and loons together as a subgroup within a greatly expanded order Ciconiiformes, a radical move which by now has been all but rejected: their "Ciconiiformes" merely 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.[5] Mounting evidence pointed to the shoebill as a close relative of pelicans.[4] This also included microscopic analysis of eggshell structure by Konstantin Mikhailov in 1995, who found that the shells of pelecaniform eggs (including those of the shoebill but not the tropicbirds) were covered in a thick microglobular material.[6] Reviewing genetic evidence to date, Cracraft and colleagues surmised that pelicans were sister to the shoebill with the hamerkop as the next earlier offshoot.[7] Ericson and colleagues sampled five nuclear genes in a 2006 study spanning the breadth of bird lineages, and came up with pelicans, shoebill and hamerkop in a clade.[8] Hackett and colleagues sampled 32 kilobases of nuclear DNA and recovered shoebill and hamerkop as sister taxa, pelicans sister to them, and herons and ibises as sister groups to each other with this heron and ibis group a sister to the pelican/shoebill/hamerkop clade.[9]

The current International Ornithological Committee classification has pelicans grouped with the shoebill (Balaenicipitidae), hamerkop (Scopidae), ibises and spoonbills (Threskiornithidae), and herons, egrets and bitterns (Ardeidae).[10]

Pelecaniformes

Threskiornithidae

Ardeidae

Scopidae

	Balaenicipitidae

	Pelecanidae

Recent research strongly suggests that the similarities between the Pelecaniformes as traditionally defined are the result of convergent evolution rather than common descent, and that the group is paraphyletic.[11] 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 the respective family or genus accounts; one little-known prehistoric Pelecaniforms, however, cannot be classified accurately enough to assign them to a family. This is "Sula" ronzoni from Early Oligocene rocks at Ronzon, France,which was initially believed to be a sea-duck and possibly 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 also includes groups such as penguins and Procellariiformes. Quite a lot of fossil bones from around the Cretaceous–Paleogene boundary cannot be firmly 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 apparently basal taxa, the following show some similarities to the traditional Pelecaniformes:

Lonchodytes (Lance Creek Late Cretaceous of Wyoming, US)
Torotix (Late Cretaceous)
Tytthostonyx (Late Cretaceous/Early Palaeocene)
Cladornis (Deseado Early Oligocene of Patagonia, Argentina)
"Liptornis"—a nomen dubium

The proposed Elopterygidae—supposedly a family of Cretaceous Pelecaniformes—are neither monophyletic nor does Elopteryx appear to be a modern bird.[12]
References

Mayr, G. et al. (2018) A fossil heron from the early Oligocene of Belgium - the earliest temporally well-constrained record of the Ardeidae. Ibis, 161(1) DOI:10.1111/ibi.12600
Kuhl., H.; Frankl-Vilches, C.; Bakker, A.; Mayr, G.; Nikolaus, G.; Boerno, S. T.; Klages, S.; Timmermann, B.; Gahr, M. (2020). "An unbiased molecular approach using 3'UTRs resolves the avian family-level tree of life". Molecular Biology and Evolution. 38: 108–127. doi:10.1093/molbev/msaa191. PMC 7783168. PMID 32781465.
Jarvis, E.D. et al. (2014) Whole-genome analyses resolve early branches in the tree of life of modern birds. Science, 346(6215):1320-1331. DOI: 10.1126/science.1253451
Hedges, S.Blair; Sibley, Charles G (1994). "Molecules vs. morphology in avian evolution: the case of the "pelecaniform" birds". PNAS. 91 (21): 9861–65. doi:10.1073/pnas.91.21.9861. PMC 44917. PMID 7937906.
Mayr, G. (2007). "Avian higher-level phylogeny: Well-supported clades and what we can learn from a phylogenetic analysis of 2954 morphological characters". Journal of Zoological Systematics and Evolutionary Research. 46: 63–72. doi:10.1111/j.1439-0469.2007.00433.x. S2CID 59486699.
Mikhailov, Konstantin E. (1995). "Eggshell structure in the shoebill and pelecaniform birds: comparison with hamerkop, herons, ibises and storks". Canadian Journal of Zoology. 73 (9): 1754–70. doi:10.1139/z95-207.
Cracraft, Joel; Barker, F. Keith; Braun, Michael J.; Harshman, John; Dyke, Gareth J.; Feinstein, Julie; Stanley, Scott; Cibois, Alice; Schikler, Peter; Beresford, Pamela; García-Moreno, Jaime; Sorenson, Michael D.; Yuri, Tamaki & Mindell, David P. (2004): Phylogenetic Relationships Among Modern Birds (Neornithes): Toward an Avian Tree of Life. In: Cracraft, J. & Donoghue, M.J. (eds.): Assembling the Tree of Life: 468-489. Oxford University Press, New York. ISBN 0-19-517234-5 PDF fulltext
Ericson, P. G. P.; Anderson, C. L.; Britton, T.; Elzanowski, A.; Johansson, U. S.; Källersjö, M.; Ohlson, J. I.; Parsons, T. J.; Zuccon, D.; Mayr, G. (2006). "Diversification of Neoaves: integration of molecular sequence data and fossils". Biology Letters. 2 (4): 543–547. doi:10.1098/rsbl.2006.0523. PMC 1834003. PMID 17148284.
Hackett, Shannon J.; Kimball, Rebecca T.; Reddy, Sushma; Bowie, Rauri C. K.; Braun, Edward L.; Braun, Michael J.; Chojnowski, Jena L.; Cox, W. Andrew; et al. (2008). "A Phylogenomic Study of Birds Reveals Their Evolutionary History". Science. 320 (5884): 1763–68. doi:10.1126/science.1157704. PMID 18583609. S2CID 6472805.
International Ornithological Committee (2 January 2012). "Ibises to Pelicans & Cormorants". IOC World Bird Names: Version 2.11. WorldBirdNames.org. Retrieved 30 April 2012.
Mayr (2003)

Mortimer (2004)