Osteoglossiformes

Osteoglossiformes Template:IPAc-en, meaning "bony tongues" in Ancient Greek, is a relatively primitive order of ray-finned fish that contains two sub-orders, the Osteoglossoidei and the Notopteroidei. All of at least 245 living species inhabit freshwater. They are found in South America, Africa, Australia and southern Asia, having first evolved in Gondwana before that continent broke up.<ref name=EoF/> In 2008, several new species of marine osteoglossiforms were described from the Danish Eocene Fur Formation, dramatically increasing the diversity of this group. This implies that the Osteoglossomorpha is not a primary freshwater fish group with the osteoglossiforms having a typical Gondwana distribution.<ref>Bonde, N., 2008: Osteoglossomorphs of the marine Lower Eocene of Denmark – with remarks on other Eocene taxa and their importance for palaeobiogeography. Geological Society, London, Special Publications; 2008; v. 295; p. 253-310</ref>

The Gymnarchidae (the only species being Gymnarchus niloticus, the African knifefish<ref name=fishbase>{{#invoke:Cite taxon|main|fishbase|genus=Gymnarchus|species=niloticus|subspecies=}}</ref>) and the Mormyridae<ref name=EoFmormyridae>Template:Cite book</ref> are weakly electric fish able to sense their prey using electric fields.

The mooneyes (Hiodontidae) are often classified here, but may also be placed in a separate order, Hiodontiformes.

Members of the order are notable for having toothed or bony tongues, and for having the forward part of the gastrointestinal tract pass to the left of the oesophagus and stomach (for all other fish it passes to the right). In other respects, osteoglossiform fishes vary considerably in size and form; the smallest is Pollimyrus castelnaui, at just Template:Convert long, while the largest, the arapaima (Arapaima gigas), reaches as much as Template:Convert.<ref name=EoF>Template:Cite book</ref>

Phylogeny

Phylogeny based on the following works:<ref name="Deepfin">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>Lavoué, S., Sullivan J. P., & Hopkins C. D. (2003): Phylogenetic utility of the first two introns of the S7 ribosomal protein gene in African electric fishes (Mormyroidea: Teleostei) and congruence with other molecular markers. Biological Journal of the Linnean Society. 78, 273-292. PDF Template:Webarchive</ref><ref>Sullivan, J. P., Lavoué S., & Hopkins C. D. (2000): Molecular systematics of the African electric fishes (Mormyroidea: Teleostei) and a model for the evolution of their electric organs. Journal of Experimental Biology. 203, 665-683. PDF Template:Webarchive</ref>

Families

Eschmeyer's Catalog of Fishes does not recognise suborders within the order Osetglossiformes and recognises the following families:<ref name = ECoF>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

• Family Pantodontidae Peters, 1876 (freshwater butterfly fishes)
• Family Osteoglossidae Bonaparte, 1845 (bonytongues)
• Family Arapaimidae Bonaparte, 1846 (arapaimas)
• Family Notopteridae Bleeker, 1851 (featherfin knifefishes or featherbacks)
  • Subfamily Notopterinae Bleeker, 1851 (Asiatic featherbacks)
  • Subfamily Xenomystinae Greenwood, 1963 (African knifefishes)
• Family Mormyridae Bonaparte, 1831 (elephantfishes)
• Family Gymnarchidae Bleeker, 1859 (abas)

External links

• Osteoglossiforms for aquaria
• Li, Guo-Qing and Wilson, Mark V. H. 1998. Osteoglossomorpha. Bonytongues. Version 6 October 1998. [1] in The Tree of Life Web Project
• Template:Cite journal