Cyprinodon milleri, a New Species of Pupfish (Family Cyprinodontidae) from Death Valley, California

Abstract

Cyprinodon milleri is the fifth known species of its genus found in the Death Valley system, Nevada-California. Its entire population lives below mean sea level, in what may be one of the more extreme fish habitats yet discovered. Water temperatures range from near freezing in winter to more than 40 C in summer, and the fish is capable of survival in a salinity range from 0.0 to 78.5 g/l. The new species differs from its nearest apparent relatives by having a shorter and narrower caudal peduncle, a shorter predorsal length, fewer lachrymal pores, more scales, far larger jaw teeth that lack any prominent, central ridge, and pelvic fins reduced or absent. C. milleri appears to have undergone exceedingly rapid speciation because of its extreme habitat and isolation.