Editing Sunbittern (section)

==Taxonomy==

The sunbittern was traditionally placed in the [[Gruiformes]], but this was always considered preliminary. Altogether, the bird is most similar to another bird that was provisionally placed in the Gruiformes, the [[kagu]] (''Rhynochetos jubatus'').<ref>Houde ''et al.'' (1997) Phylogeny and evolution of 12S rDNA in Gruiformes (Aves). In: Mindell, D. P. (ed.), Avian Molecular Evolution and Systematics. Academic Press, San Diego. Pp. 121–158.</ref><ref>{{Cite journal|last1=Oliveira|first1=Edivaldo H. C. de|last2=Ferguson-Smith|first2=Malcolm A.|last3=O´Brien|first3=Patricia C. M.|last4=Tagliarini|first4=Marcella Mergulhão|last5=Santos|first5=Michelly da Silva dos|last6=Monte|first6=Amanda Almeida|last7=Furo|first7=Ivanete de Oliveira|date=2015-12-01|title=Cytotaxonomy of Eurypyga helias (Gruiformes, Eurypygidae): First Karyotypic Description and Phylogenetic Proximity with Rynochetidae|journal=PLOS ONE|language=en|volume=10|issue=12|pages=e0143982|doi=10.1371/journal.pone.0143982|issn=1932-6203|pmc=4666659|pmid=26624624|bibcode=2015PLoSO..1043982F|doi-access=free}}</ref> Molecular studies seem to confirm that the kagu and sunbittern are each other's closest living relatives and have a similar wing display.<ref>Fain & Houde (2004) [http://biology-web.nmsu.edu/houde/Parallel_radiations.pdf Parallel radiations in the primary clades of birds] {{Webarchive|url=https://web.archive.org/web/20130407204436/http://biology-web.nmsu.edu/houde/Parallel_radiations.pdf |date=7 April 2013 }}. ''[[Evolution (journal)|Evolution]]'' 58(11): 2558–2573.</ref><ref>Ericson ''et al.'' (2006) [http://www.senckenberg.de/files/content/forschung/abteilung/terrzool/ornithologie/neoaves.pdf Diversification of Neoaves: Integration of molecular sequence data and fossils]. Biology Letters 2 (4):  pp. 543–547</ref> They are probably not Gruiformes (though the proposed [[Metaves]] are just as weakly supported).<ref>Morgan-Richards ''et al.'' (2008) Bird evolution: testing the Metaves clade with six new mitochondrial genomes. BMC Evolutionary Biology 8 (20).</ref> Altogether, the two species seem to form a minor [[Gondwana]]n lineage which could also include the extinct [[adzebill]]s and/or the [[mesite]]s, and is of unclear relation to the Gruiformes proper. Notably, the kagu and mesites also have [[powder down]].

An indeterminate fossil eurypygid has been documented from the [[Green River Formation]] of [[Wyoming]], USA. This specimen, known from a full skeleton, is the oldest and only known fossil of the group, and suggests that eurypygids had a much more northernly range in the past. This specimen has been figured in several studies, and was given the unofficial name "''Eoeurypyga olsoni''" in a 2003 dissertation, but as-of-yet remains unnamed.<ref name=":04">{{Citation |last=Mayr |first=Gerald |title=Phaethontiformes and Aequornithes: The Aquatic and Semi-aquatic Neaovian Taxa |date=2022 |work=Paleogene Fossil Birds |series=Fascinating Life Sciences |pages=117–152 |editor-last=Mayr |editor-first=Gerald |url=https://link.springer.com/chapter/10.1007/978-3-030-87645-6_7 |access-date=2024-10-15 |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-030-87645-6_7 |isbn=978-3-030-87645-6|url-access=subscription }}</ref><ref>{{Cite thesis |last=Weidig |first=Ilka |title=Fossil birds from the lower eocene Green River formation (USA) |date=2003 |publisher=Universitätsbibliothek Johann Christian Senckenberg |url=https://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/year/2007/docId/1561}}</ref>

===Subspecies===
The sunbittern was formerly treated as two species (''E. helias'' and ''E. major''), but now they are treated as a single species with considerable variation between the [[subspecies]]. The three subspecies are recognised on the basis of plumage characters and size. The three subspecies are [[allopatric]].<ref name="HBW3"/>

* ''E. h. helias'' {{small|([[Peter Simon Pallas|Pallas]], 1781)}} – Amazonian sunbittern
* ''E. h. major'' {{small|[[Gustav Hartlaub|Hartlaub]], 1844}} – northern sunbittern
* ''E. h. meridionalis'' {{small|[[Hans von Berlepsch|Berlepsch]] & [[Jan Sztolcman|Stolzmann]], 1902}} – foothill sunbittern