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Hiodontiformes
Article by: Boschung, Herbert Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama. Publication year: 2014 DOI: http://dx.doi.org/10.1036/1097-8542.803340 (http://dx.doi.org/10.1036/1097-8542.803340)
Content
• Bibliography • Additional Readings
An order formerly in Osteoglossiformes but now independent, with the two orders comprising the extant Osteoglossomorpha, a primitive group of teleost fishes. The order Hiodontiformes consists of one family, one genus, and two extant species, Hiodon alosoides (goldeye) and H. tergisus (mooneye). Hiodontids superficially resemble clupeids and for many years were classified as clupeiforms. The body is deep and laterally compressed and has a ventral keel, but the keel is not serrated as in most clupeids; the eyes are far forward and large, with the diameter greater than the length of the snout; the scales are large and cycloid and either bright silvery or golden; the anal fin base is much longer than the dorsal fin base; and the caudal fin is forked (see illustration). The goldeye differs from the mooneye in having 9 or 10 principal dorsal fin rays versus 11 or 12, and a ventral keel extending anteriorly past the pelvic fins versus not extending anteriorly past the pelvic fins. See also: Clupeiformes (/content/clupeiformes/142500); Osteichthyes (/content/osteichthyes/478500); Osteoglossiformes (/content/osteoglossiformes/478600)
Example of a hiodontid. (From J. S. Nelson, Fishes of the World, 4th ed., Wiley, New York, 2006)
Both species are limited to the freshwaters of North America between the Continental Divide and the Appalachians. Hiodon alosoides has the greatest north-south distribution of North American freshwater fishes, ranging from 69° to 31°N latitude and including the MacKenzie River delta and Great Plains of northwestern Canada, isolated populations in the Hudson River drainage in eastern Canada, and populations southward in large rivers of the Mississippi Basin to Louisiana and Alabama. The species is
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absent from the Great Lakes basin. Hiodon tergisus ranges between latitudes 60° and 30°N, including the Mississippi River basin east of the Great Plains and west of the Appalachians to the Gulf Coast, parts of the Great Lakes, the St. Lawrence River, and tributaries to Hudson Bay northward.
Both species are opportunistic feeders, foraging in late evening and at night, at the surface, primarily on aquatic insects, crustaceans, mollusks, small fishes, and frogs. Hiodon alosoides attains a total length of 52 cm (20.5 in.), and H. tergisus attains a total length of 47 cm (18.5 in.).
Herbert Boschung
Bibliography
E. J. Hilton, Comparative osteology and phylogenetic systematics of fossil and living bony tongue fishes (Actinopterygii, Teleostei, Osteoglossomorpha), Zool. J. Linn. Soc., 137:1–100, 2003; DOI: 10.1046/j.1096 3642.2003.00032.x (http://dx.doi.org/10.1046/j.1096-3642.2003.00032.x)
G.-Q. Li and M. V. H. Wilson, Phylogeny of Osteoglossomorpha, pp. 163–174, in M. L. J. Stiassny, L. R. Parenti, and G. D. Johnson (eds.), Interrelationships of Fishes, Academic Press, San Diego, 1996
J. S. Nelson, Fishes of the World, 4th ed., Wiley, New York, 2006
Additional Readings
G. S. Helfman et al., The Diversity of Fishes: Biology, Evolution, and Ecology, 2d ed., Wiley-Blackwell, Chichester, West Sussex, UK, 2009
Tree of Life Web Project: Hiodontiformes (http://tolweb.org/Hiodontiformes)
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