Part 3

Specimen No. 4253 is mostly pallid, resembling Gila much more than Rhinichthys in pigmentation. A mid-dorsal dark streak is conspicuous in the hybrid, especially anteriorly, but is less intense than in Gila. Rhinichthys lacks a well-developed dorsal stripe. The preorbital and suborbital areas are more heavily pigmented in the hybrid than in Gila, but not nearly so dark as in Rhinichthys. The hybrid has a faint dark basicaudal spot that is variably developed in Rhinichthys but absent in Gila.

=Notropis venustus venustus × Notropis whipplei=: KU 3516 (a male, 47.8 mm. in standard length), from Arkansas, Sevier Co., Winters Creek where it is crossed by U. S. Highway 71, 5 mi. N of Little River Bridge, March 8, 1956. Compared in Table 5 with four specimens of N. whipplei, KU 3517 (45.0-52.6 mm. in standard length, mean 50.6 mm.), same locality and date as KU 3516; four specimens of N. v. venustus, KU 3510 (44.5-49.6 mm. in standard length, mean 47.3 mm.), Louisiana, Winn Parish, Little Naches Bayou on U. S. Highway 71, 8.8 mi. NW Montgomery, March 4, 1956; three specimens of Notropis lutrensis (Baird and Girard) × N. v. venustus, KU 3510 (43.3-47.3 mm. in standard length, mean 44.7 mm.), same locality and date as N. v. venustus above; and with tabulated data on N. v. venustus from Gibbs (1957a:185-186). All specimens are from the lower Red River Drainage; other series of N. whipplei, N. venustus, and N. lutrensis × N. venustus, from the Red River Drainage and elsewhere, were examined but are not tabulated because of differences in size, and because of geographic variability that has been discussed by Gibbs (1957a).

The Subgenus Cyprinella of Notropis, to which N. venustus and N. whipplei belong, has been studied intensively by Gibbs (1957a and b). Notropis venustus differs conspicuously from N. whipplei in having a large dark basicaudal spot; also, N. venustus usually has 8 (rather than 9) anal rays, and 15 (rather than 13) scales above the lateral line immediately anterior to the dorsal fin. Specimens of N. v. venustus from the Red River Drainage, where the most robust representatives of the species are found, differ from N. whipplei in depth of head, body, and caudal peduncle (Table 5).

KU 3516 has a composite of the 9-rayed anal fin of N. whipplei and the caudal spot (albeit diffuse) of N. venustus; and, the hybrid is intermediate in body-proportions that distinguish the two species, especially depth of head, body, and caudal peduncle. In other features KU 3516 has values within the overlapping ranges of variation of whipplei and venustus except that the ratio of postdorsal length to standard length is extremely long in the hybrid, and the ratio of prepelvic length to standard length is extremely short (Table 5). Both extreme values for the hybrid seem to result from the cumulative influence of characters in which the parental species differ slightly in mean value (especially head-length, in which the hybrid is like whipplei, and caudal peduncle-length, in which the hybrid approaches venustus, despite the 9-rayed anal fin of the hybrid). The basicaudal spot of the hybrid is like that of N. v. venustus except for being less intense.

Notropis venustus hybridizes extensively with N. lutrensis (Hubbs, Kuehne, and Ball, 1953:226-230; Hubbs and Strawn, 1956), and that combination occurs in streams near the locality where KU 3516 was taken. KU 3516 resembles N. lutrensis × N. v. venustus in many ways, but is more slender than the latter hybrid. The depth of head, body, and caudal peduncle are greater in N. lutrensis than in N. venustus (much greater than in N. whipplei); therefore, specimens of N. lutrensis × N. venustus are usually deeper than N. venustus, whereas KU 3516 is less deep. KU 3516 has a rather sharp snout and thin, straight lips that are strongly suggestive of N. whipplei, rather than N. lutrensis, in which the snout is rounded and the lips are more obliquely decurved. There is less pigment underlying the anterior lateral-line scales in KU 3516 than in N. lutrensis × N. venustus, and melanophores on the scale-pockets of KU 3516 are arranged in narrower, more distinct submarginal bars than in N. lutrensis × N. venustus. Because of the difference in pigmentation, the lateral scales of N. whipplei (and of KU 3516) appear more narrowly diamond-shaped than the lateral scales of N. lutrensis or N. lutrensis × N. venustus. The lengths and heights of the scales are approximately the same in all three species.

Winters Creek, where KU 3516 was taken, flowed approximately five cubic feet per second at the time our collection was made; a landowner on the stream stated that it had been dry, except for pools, in the previous two summers. The water was somewhat gray, but nearly clear. The habitat consisted mainly of short riffles, with average depth of four inches, and pools to depths of two feet. Twelve species of fish, including N. whipplei but not N. lutrensis or N. venustus, were found; other minnows were Semotilus atromaculatus, N. chalybaeus, N. cornutus, N. umbratilis, and Campostoma anomalum.

LITERATURE CITED

EVANS, H. E., and DEUBLER, JR., E. E.

1955. Pharyngeal tooth replacement in Semotilus atromaculatus and Clinostomus elongatus, two species of cyprinid fishes. Copeia, 1955 (1):31-41, February 18.

GIBBS, JR., R. H.

1957a. Cyprinid fishes of the Subgenus Cyprinella of Notropis. III. Variation and subspecies of Notropis venustus (Girard). Tulane Studies in Zoology, 5(8):175-203, August 7.

1957b. Cyprinid fishes of the Subgenus Cyprinella of Notropis. I. Systematic status of the Subgenus Cyprinella, with a key to the species exclusive of the lutrensis-ornatus complex. Copeia, 1957(3):185-195, August 26.

HAY, O. P.

1888. A contribution to the knowledge of the fishes of Kansas. Proc. U. S. Nat. Mus., 10:242-253, March 1.

HUBBS, C. L.

1951. Identification of cyprinid fish reported from Kansas as Squalius elongatus. Trans. Kansas Acad. Sci., 54(2):190-192, June 15.

1955. Hybridization between fish species in nature. Systematic Zoology, 4(1):1-20, March.

HUBBS, C. L., and LAGLER, K. F.

1958. Fishes of the Great Lakes Region. Cranbrook Inst. Sci., Bull. 26, revised ed., xiii + 213 pp.

HUBBS, C. L., and MILLER, R. R.

1943. Mass hybridization between two genera of cyprinid fishes in the Mohave Desert, California. Papers Michigan Acad. Sci., Arts, and Lett., 28(1942):343-378, pls. 1-4, February.

HUBBS, C.

1956. Relative variability of hybrids between the minnows, Notropis lepidus and N. proserpinus. Texas Jour. Sci., 8 (4):463-469, December.

HUBBS, C., KUEHNE, R. A., and BALL, J. C.

1953. The fishes of the upper Guadalupe River, Texas. Texas Jour. Sci., 5(2):216-244, June.

HUBBS, C., and STRAWN, K.

1956. Interfertility between two sympatric fishes, Notropis lutrensis and Notropis venustus. Evolution, 10(4):341-344, December.

JOHNSON, R.