Mylopharodon conocephalus

See Moyle et al. (1989) for nomenclatural history. Perhaps should be included in the genus Ptychocheilus (Lee et al. 1980), but a morphometric phylogenetic analysis of Mylopharodon and Ptychocheilus by Mayden et al. (1991) concluded that the best arrangement is to retain Mylopharodon as a monotypic genus distinct from Ptychocheilus.

Widely distributed in California but declining and vulnerable to local extirpation from habitat alteration (stream flow quantity and quality changes) and introduced fishes.

Range includes much of the Sacramento-San Joaquin drainage of California (widely distributed in foothill streams), from the Kern River, Kern County, in the south to the Pit River drainage in Modoc County in the north (where widely distributed south of the Goose Lake drainage, and including spotty occurrences in the main Pit River and associated hydroelectric reservoirs); also the Russian River drainage (where uncommon) (Moyle et al. 1989, Moyle 2002). This species occurs in scattered tributaries of the San Joaquin River but not in the valley reaches of the river (Moyle et al. 1989, Moyle 2002). The species is still fairly common in the mainstem Sacramento River, in the lower reaches of the American and Feather rivers, in some smaller tributary streams (e.g., Deer, Pine, and Clear creeks), and in some river reaches above foothill reservoirs (Moyle 2002). The species is absent from the Clear Lake basin and from San Francisco Bay streams except the Napa River (where now extremely rare) (Moyle 2002). Elevational range is 10-1,450 meters. The species is still widespread (though less common, especially in the southern part of the range).

This species is represented by a fairly large number of occurrences (subpopulations) and locations.

Dams and diversions have eliminated habitat and left many populations isolated and vulnerable to local extinction due to unsuitable stream temperatures and flows (Moyle 2002). Centrarchid fishes (bass, sunfish) threaten populations in foothill streams. Reservoir populations should not be regarded as "safe" populations since these also are vulnerable to large declines caused by increased populations of introduced smallmouth bass and other centrarchid basses (Moyle et al. 1989, Moyle 2002). Population crashes in Pardee, Millerton, Berryessa, Don Pedro, and Folsom reservoirs are thought to have resulted from centrarchid bass predation (see Moyle 2002).