Endangered
Hybognathus amarus
Rio Grande Silvery Minnow
Taxonomic Hierarchy
Actinopterygii (Ray-finned Fishes)
Cypriniformes (Carps and Minnows)
Cyprinidae (Carps and Minnows)
Hybognathus
Hybognathus amarus (Rio Grande Silvery Minnow)
Description
Type Locality
See Girard (1856).
Etymology
No information at this time.
Synonymy
No information at this time.
Characters
89 mm (3.50 in) TL
Dorsal region brown to olive with a broad and dark mid-dorsal stripe; lateral region silvery with dark pigmentation forming a diffuse mid-lateral stripe; ventral region white.
Pharyngeal teeth in main row typically 4-4; scales with 8 radii; 11-15 scale rows across belly (counted just in advance of pelvic insertion, excluding the lateral line scales); fewer than 45 lateral line scales; fewer than 10 soft rays on dorsal fin (Hubbs et al. 2008).
Head width about equal to distance from tip of snout to back of eye; eye contained in snout about 1.5 times; eye shorter than snout; distance from anal fin origin to end of caudal peduncle goes 2.5 or fewer times in distance from tip of snout to anal fin origin (Hubbs et al. 2008).
Predorsal scale rows not crowded except for fish with 9 or more anal fin rays; first obvious dorsal fin ray a thin splint, closely attached to the following well developed but unbranched ray, especially at tip; lower lip thin, without a fleshy lobe; lateral line usually not decurved, either straight or with a broad arch; premaxillaries protractile; upper lip separated from skin of snout by a deep groove continuous across the midline; cartilaginous ridge of lower jaw hardly evident and not separated by a definite groove from the lower lip (Hubbs et al. 2008). Intestine long and coiled, more than twice standard length (Hubbs et al. 2008).
Distribution
Once abundant throughout the Rio Grande and Pecos basins; it now exists only in scattered Rio Grande locations in New Mexico (Hubbs et al. 2008).
Apparently extirpated in Texas (Rio Grande and Pecos basins; Hubbs et al. 2008).
Abundance/Conservation Status
State Endangered (Texas); Federally Endangered (Hubbs et al. 2000); presumably extirpated in Texas. Listed as Endangered by the American Fisheries Society; status has declined since 1989; categories of threats: present or threatened destruction, modification, or reduction of habitat or range; disease or parasitism; other natural or anthropogenic factors that affect the existence of this species, including impacts of nonidigenous organisms, hybridization, competition, and/or predation (Jelks et al. 2008).
Habitat Associations
No information at this time.
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Biology
No information at this time.
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Phylogeny and Morphologically Similar Fishes
No information at this time.
Host Records
No information at this time.
Commercial or Environmental Importance
No information at this time.
References
Bestgen, K. R., D. L. Propst. 1996. Redescription, geographic variation, and taxonomic status of the Rio Grande silvery minnow, Hybognathus amarus (Girard 1856). Copeia 1996(1):41-55.
Girard, C.F. 1856. Researches upon the Cyprinoid fishes inhabiting the fresh waters of the United States of America, west of the Mississippi Valley, from specimens in the Museum of the Smithsonian Institution. Proceedings of the Academy of Natural Sciences of Philadelphia (1856) 8(5):165-213.
Hubbs, C., R.J. Edwards, and G.P. Garrett. 2008. An annotated checklist of the freshwater fishes of Texas, with keys to identification of species. Texas Journal of Science, Supplement, 2nd edition 43(4):1-87.
Jelks, H.L., S.J. Walsh, N.M. Burkhead, S. Contreras-Balderas, E. Diaz-PArdo, D.A. Hendrickson, J. Lyons, N.E. Mandrak, F. McCormick, J.S. Nelson, S.P. Platania, B.A. Porter, C.B. Renaud, J.J. Schmitter-Soto, E.B. Taylor, and M.L. Warren, Jr. 2008. Conservation status of imperiled North American freshwater and Diadromous Fishes. Fisheries 33(8):372-407.
Comments On Hybognathus amarus