The alternate spelling "Gonorhynchiformes", with an "h", is frequently seen but not official.
Gonorynchiformes have small mouths and no teeth. They are the sole group in the clade Anotophysi, a subgroup of the superorder Ostariophysi. They are characterized by a primitive Weberian apparatus formed by the first three vertebrae and one or more cephalic ribs within the head. This apparatus is believed to be a hearing organ, and is found in a more advanced and complex form in the related cypriniform fish, such as carp.[1] Also like the cypriniforms, the gonorynchiforms produce a substance from their skin when injured that dissolves into the water and acts an alarm signal to other fish.[2]
Taxonomy
Although many of the families are rather small, there are several fossil genera. This listing of the groups of Gonorynchiformes includes fossil fish with a short description.[1] They are listed in approximate order of how primitive their characteristics are.
^ abNelson, Joseph, S. (2006). Fishes of the World. John Wiley & Sons, Inc. ISBN0-471-25031-7.{{cite book}}: CS1 maint: multiple names: authors list (link)
^Banister, Keith F. (1998). Paxton, J.R.; Eschmeyer, W.N. (eds.). Encyclopedia of Fishes. San Diego: Academic Press. pp. 96–97. ISBN0-12-547665-5.
^Thomas J. Near, Alex Dornburga, Matt Friedman (2014): Phylogenetic relationships and timing of diversification in gonorynchiform fishes inferred using nuclear gene DNA sequences (Teleostei: Ostariophysi). Molecular Phylogenetics and Evolution, DOI:10.1016/j.ympev.2014.07.013
