Picture by Chad Thomas, Texas State University-San Marcos

Machrybopsis australis

prairie chub

Type Locality

Red River, 6 to 9 miles southwest of Hollis, Harmon County, Oklahoma (Hubbs and Ortenburger 1929).

Etymology/Derivation of Scientific Name

Macr – Greek, meaning “long”, referring to elongated forms of Hybopsis (Scharpf 2005); australis – Latin, meaning “southern”, probably referring to the more southerly range of this species to its putative sister species, Macrhybopsis tetranema, the peppered chub; the common name, prairie chub, refers to the prairies drained by streams in the range of M. australis (Eisenhour 2004).

Synonymy

Eisenhour (1999) recognized Macrhybopsis australis as distinct species within the M. aestivalis complex. See Eisenhour (1997) for complete synonymy.

Extrarius australis Hubbs and Ortenburger 1929:26-28.

Hybopsis aestivalis australis Davis and Miller (1967); Miller and Robison 1973:63-64; Douglas 1974:100.

Macrhybopsis australis Eisenhour (1999); Underwood et al. (2003); Eisenhour (2004); Hubbs et al. 2008:21.

Characters

Maximum size: 70 mm (2.76 in) TL (Eisenhour 2004).

Coloration: Pallid and translucent, in life, pale yellow or gray dorsally, silvery white ventrally, with broad silver mid-lateral stripe; small melanophores scattered over dorsolateral surface of body, not concentrated on margin or submargin of scales; poorly defined mid-lateral stripe present to nearly absent, composed of small, often X-shaped melanophores, centered one scale row above lateral line; dorsal fin with fairly dark pigment on basal third of first 3-5 rays; pigment on distal portion of rays lacking or reduced. Pectoral, pelvic, and anal fins generally lacking pigment; rarely some pigment on pectoral rays (Eisenhour 2004).

Counts: Pharyngeal teeth 0,4-4,0; 19 (16-20) principal caudal fin soft rays; 7 (6-8) anal fin soft rays; 7-8 (6-9) pelvic fin soft rays; 13-15 (12-17) pectoral fin soft rays; 36-42 (34-44) lateral-line scales; 2-16 (0-19) predorsal scales; 5-6 (4-7) scales above lateral line; 4-5 (4-6) scales below lateral line; 12-16 (12-17) caudal peduncle scales; 12-16 (10-16) infraorbital pores; 10-12 (9-14) preoperculomandibular pores; 35-36 (34-36) total vertebrae; 16-18 (16-19 precaudal vertebrae; 17-19 caudal vertebrae (Eisenhour 2004).

Mouth position: Inferior and horizontal; width equal to head width when viewed ventrally; lips very fleshy and thickened posteriorly (Eisenhour 2004).

Body shape: Fusiform with moderately slender caudal peduncle; head conical and flattened ventrally with long and relatively pointed snout (Eisenhour 2004).

Morphology: Nape fully scaled or with scattered embedded scales, rarely naked; belly posterior to pelvic fin bases naked to fully scaled; belly just anterior to pelvic fin bases naked or with few scales not forming a bridge across belly. Anal and dorsal fins slightly falcate; pelvic fins pointed; pectoral fins long and falcate, reaching past bases of pelvic fins in adult males and just reaching bases of pelvic fins in adult females; eyes tiny and round (or nearly so); 2 prominent pairs of maxillary barbels present, the more posterior pair > than orbit length and the anterior pair > 50% of orbit length; cutaneous taste buds expanded into large papillae on gular area; in both sexes, genital papillae poorly developed as small conical or cylindrical extensions; gill rakers on first arch absent or present as 1-3 dorsal rudiments (Eisenhour 2004). In large nuptial males, pectoral rays 2-10 are greatly thickened with rows of small, conical, antrorse, recurved biserial tubercles; basal part of rays and primary branches each with 1-2 rows of tubercles; 2 tubercles per fin ray segment on posterior primary branch, 1-2 tubercles per segment on the anterior primary branch; tubercles arranged uniserially on secondary branches (Eisenhour 2004).

Distribution (Native and Introduced)

U.S. distribution: Endemic to the upper Red River basin (Eisenhour 2004; Hubbs et al. 2008).

Texas distribution: Upper Red River basin (Eisenhour 2004; Hubbs et al. 2008).

Abundance/Conservation status (Federal, State, Non-governmental organizations)

Special Concern status in Texas (Hubbs et al. 2008).

Habitat Associations

Macrohabitat: Medium to large streams (Eisenhour 2004).

Mesohabitat: Found in flowing water over coarse sand and fine gravel substrates in streams; occupies intermittent streams that may dry to isolated, salt-encrusted pools (Winston et al. 1991; Eisenhour 2004). Distribution is correlated with high levels of dissolved salts (Taylor et al. 1993; Eisenhour 2004; Higgins and Wilde 2005); reported from waters with salinities up to 19.6‰ (Echelle et al. 1972; Eisenhour 2004).

Biology

Spawning season: No information at this time.

Spawning habitat: No information at this time.

Spawning Behavior: No information at this time.

Fecundity: No information at this time.

Age at maturation: No information at this time.

Migration: No information at this time.

Growth and Population structure:  No information at this time.

Longevity: No information at this time.

Food habits: Primarily taste-feeders – “mouth tasters” (Davis and Miller 1967); observed (in captivity) swimming over the bottom with pectoral fins spread widely and barbels in contact with the sand substrate until cutaneous taste buds on the barbels, fins and body apparently detected the food items.

Phylogeny and morphologically similar fishes

Macrhybopsis australis distinguished from the shoal chub (M. hyostoma), by the combination of two pairs of well-developed barbels, the posterior pair > orbit length and the anterior pair> 50% of orbit length, and modally 7 anal soft fin  rays (Eisenhour 2004). M. australis and the peppered chub (M. tetranema), a species endemic to the upper Arkansas River basin, are sister species (Underwood et al. 2003; Eisenhour 2004).

Host Records

 No information at this time.

Commercial or Environmental Importance

No information at this time.

References

Davis, B.J., and R.J. Miller. 1967. Brain patterns in minnows of the genus Hybopsis in relation to feeding habits. Copeia 1967(1):1-39.

Douglas, N.H. 1974. Freshwater Fishes of Louisiana. Claitor’s Publishing Division, Baton Rouge, Louisiana. 443.

Echelle, A.A., A.F. Echelle, and C.G. Hill. 1972. Interspecific interactions and limiting factors of abundance and distribution in the Red River pupfish, Cyprinodon rubrofluviatilis. American Midland Naturalist 88:109-130.

Eisenhour, D.J. 1997. Systematics, variation and speciation of the Macrhybopsis aestivalis complex (Cypriniformes: Cyprinidae) west of the Mississippi River. Unpubl. PhD Dissertation. Southern Illinois Univ., Carbondale. 260 pp.

Eisenhour, D. 1999. Systematics of Macrhypbopsis tetranema (Cypriniformes: Cyprinidae). Copeia 1999: 969-980.

Eisenhour, D. J. 2004. Systematics, variation, and speciation of the Macrhybopsis aestivalis complex west of the Mississippi River. Bulletin Alabama Museum of Natural History 23:9-48.

Higgins, C.L., and G.R. Wilde. 2005. The role of salinity in structuring fish assemblages in a prairie stream system. Hydrobiologia 549:197-203.

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, 2^nd edition 43(4):1-87.

Hubbs, C.L., and A.I. Ortenburger. 1929. Further notes on the fishes of Oklahoma, with descriptions of new species of Cyprinidae. Publ. Univ. Okla. Biol. Surv. 1(2):17-43.

Miller, R.J., and H.W. Robison. 1973. The Fishes of Oklahoma. Oklahoma State University Press, Stillwater, Oklahoma. 246 pp.

Scharpf, C. 2005. Annotated checklist of North American freshwater fishes, including subspecies and undescribed forms, Part 1: Petromyzontidae through Cyprinidae. American Currents, Special Publication 31(4):1-44.

Taylor, C.M., M.R. Winston, and W.J. Matthews. 1993. Fish species-environment and abundance relationships in a Great Plains river system. Ecography 16(1):16-23.

Underwood, D.M., A.A. Echelle, D.J. Eisenhour, M.D. Jones, A.F. Echelle, and W.L. Fisher. 2003. Genetic variation in western members of the Macrhybopsis aestivalis complex (Teleostei: Cyprinidae), with emphasis on those of the Red and Arkansas River basins. Copeia 2003(3):493-501.

Winston, M.R., C.M. Taylor, and J. Pigg. 1991. Upstream extirpation of four minnow species due to damming of a prairie stream. Transactions of the American Fisheries Society 120:98-105.