7146

• UCREFRP Catalog Number: 7146
• Author: Hubbs, C. L. and R. R. Miller
• Title: Hybridization in Nature Between the Fish Genera
• USFW Year: 1953
• Copyright Material: YES

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[Reprinted from PAPERS OF THE MICHIGA_'1 ACADEMY OF SCIENCE, ARTS, AND
LETTERS, VOL. XXXVIII, 1952. Published 1953]

HYBRIDIZATION IN NATURE BETvVEEN THE
FISH GENERA CATOSTOJ;IUS AND
XYRAUCHEN*

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CARL L. HUBBS
Scripps lnstitution of Oceanography, La Jolla, California

ROBERT RUSH MILLER
University of Michigan

IT HAS recently been demonstrated that the Catostomidae (suck-
ers) are to be included among the several families of freshwater
teleost fishes that rather commonly hybridize interspecifically in
nature (Hubbs, Hubbs, and Johnson, 1943; Hubbs and Hubbs,
1947; Miller and Miller, 1948, p. 180). In these studies it has been
indicated that several species of the North American genus Cato-
stomus crossbreed in nature with other species of this genus and with
species currently referred to the closely related genus Pantosteus.
Still more recently we have determined that suckers of the genus
Catostomus also hybridize, in western North America, with species
that are now classified under two other distinct genera, Chasmistes
and Xyrauchen. In this paper we deal with the Catostomus X
Xyrauchen hybrids, referring them to two new interspecific combina-
tions. Both species of Catostomus involved have previously been
recognized as parents of other natural hybrids.
The species that hybridize with Xyrauchen are identified as
Catostomus latipinnis Baird and Girard in the upper Colorado River
system and as C. ins ignis Baird and Girard in the Gila River tribu-
tary system. There are no suggestions that they might instead be
species' of Pantosteus, for, unlike the numerous known hybrid in-
dividuals involving that genus, the specimens examined exhibit no
trace of the highly modified lip characters of Pantosteus. Other
species of Catostomus occurring in the upper Colorado waters are
also excluded by the characters of the hybrids. The slender caudal

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* Contributions from the Scripps Institution of Oceanography, New Series, No.
598, and from the Museum of Zoology, University of Michigan.

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