page_title: Darter
section_title: Systematics and evolution
hierarchical_section_title: Darter / Systematics and evolution
caption_attribution_description: English: Australian Darter, Anhinga novaehollandiae; wild bird
context_page_description: The darters, anhingas, or snakebirds are mainly tropical waterbirds in the family Anhingidae, which contains a single genus, Anhinga. There are four living species, three of which are very common and widespread while the fourth is rarer and classified as near-threatened by the IUCN. The term snakebird is usually used without any additions to signify whichever of the completely allopatric species occurs in any one region. It refers to their long thin neck, which has a snake-like appearance when they swim with their bodies submerged, or when mated pairs twist it during their bonding displays. "Darter" is used with a geographical term when referring to particular species. It alludes to their manner of procuring food, as they impale fishes with their thin, pointed beak. The American darter is more commonly known as the anhinga. It is sometimes called "water turkey" in the southern United States; though the anhinga is quite unrelated to the wild turkey, they are both large, blackish birds with long tails that are sometimes hunted for food.
context_section_description: The genus Anhinga was introduced by the French zoologist Mathurin Jacques Brisson in 1760 with the anhinga or American darter (Anhinga anhinga) as the type species. Anhinga is derived from the Tupi ajíŋa (also transcribed áyinga or ayingá), which in local mythology refers to a malevolent demonic forest spirit; it is often translated as "devil bird". The name changed to anhingá or anhangá as it was transferred to the Tupi–Portuguese Língua Geral. However, in its first documented use as an English term in 1818, it referred to an Old World darter. Ever since, it has also been used for the modern genus Anhinga as a whole.
  This family is very closely related to the other families in the suborder Sulae, i.e. the Phalacrocoracidae (cormorants and shags) and the Sulidae (gannets and boobies). Cormorants and darters are extremely similar as regards their body and leg skeletons and may be sister taxa. In fact, several darter fossils were initially believed to be cormorants or shags (see below). Some earlier authors included the darters in the Phalacrocoracidae as subfamily Anhingina', but this is nowadays generally considered overlumping. However, as this agrees quite well with the fossil evidence some unite the Anhingidae and Phalacrocoracidae in a superfamily Phalacrocoracoidea.
  The Sulae are also united by their characteristic display behavior, which agrees with the phylogeny as laid out by anatomical and DNA sequence data. While the darters' lack of many display behaviors is shared with gannets (and that of a few with cormorants), these are all symplesiomorphies that are absent in frigatebirds, tropicbirds and pelicans also. Like cormorants but unlike other birds, darters use their hyoid bone to stretch the gular sac in display. Whether the pointing display of mates is another synapomorphy of darters and cormorants that was dropped again in some of the latter, or whether it evolved independently in darters and those cormorants that do it, is not clear. The male raised-wing display seems to be a synapomorphy of the Sulae; like almost all cormorants and shags but unlike almost all gannets and boobies, darters keep their wrists bent as they lift the wings in display, but their alternating wing-waving, which they also show before take-off, is unique. That they often balance with their outstretched wings during walking is probably an autapomorphy of darters, necessitated by their being plumper than the other Sulae.
  The Sulae were traditionally included in the Pelecaniformes, then a paraphyletic group of "higher waterbirds". The supposed traits uniting them, like all-webbed toes and a bare gular sac, are now known to be convergent, and pelicans are apparently closer relatives of storks than of the Sulae. Hence, the Sulae and the frigatebirds – and some prehistoric relatives – are increasingly separated as the Suliformes, which is sometimes dubbed "Phalacrocoraciformes".
caption: Male Australasian darter
  A. novaehollandiae
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