7950

• UCREFRP Catalog Number: 7950
• Author: Williams, J. E. and G. R. Wilde
• Title: Taxonomic Status And Morphology Of Isolated Populations Of The White River Springfish,
• USFW Year: 1981
• Copyright Material: YES

Mormon, Hot Creek, Hiko, Ash, Moapa Valley Water District (MVWD), and Cardy Lamb. Due to
a lack of specimens and! or the rare occurrence of C. baileyi in a particular habitat, only small
numbers of specimens were examined from Lund Town Spring, Moon River Spring, Adams-McGill
Reservoir, and the Moapa River at Taylor (= Home) Ranch. Specimens were provided by The
University of Michigan Museum of Zoology (UMMZ); Arizona State University (ASU); University
of Nevada, Las Vegas (UNLV); and field collections. Type material is deposited at UMMZ and
UNL V. Field notes taken by Carl L. Hubbs when his party collected specimens from most C. baileyi
populations during the summer of 1938 provided the basis for subspecies color diagnoses.
Morphometric and meristic analyses were made as described for cyprinodonts by Miller (1948)
with the following exception. Grea test body depth, a measurement of the greatest vertical distance
between the dorsal and ventral margins, was measured with one end of the calipers placed just
anterior to the origin of the dorsal fin and the other end on the ventral margin directly below the
calipers on the dorsal margin. Gill filaments were measured and enumerated on the first arch on the
left side.
Morphometric measurements were made with precision dial calipers to the nearest 0.1 mm.
Morphometrics were analyzed by the graphical methods of Hubbs and Hubbs (1953). The basal line
indicates the sample range and the hatched rectangle represents plus and minus one standard error
of the mean (vertical line). The larger rectangle indicates 0.675 standard deviation on either side of
the mean. If no overlap occurs between the larger rectangles of two samples, the populations are
considered separable for that character at the 75% level, an accepted value of subspecific separation
(Hubbs and Hubbs 1953). Morphometric values are given in thousandths of standard length. Meristic
data are presented in frequency tables. Numbers of vertebrae were determined by radiographs for
fishes from Preston Big Spring, Mormon Spring, Hiko Spring, the outflow creek below Ash Spring,
and Cardy Lamb Spring. Precaudal, caudal, and total vertebrae numbers are reported. The first
caudal vertebra was defined as the first vertebra with fused transverse processes. Enumeration of
vertebral centra was employed as an indication of vertebrae number.
In many respects, the Preston Big Spring and Mormon Spring populations represent the two
extremes in environmental conditions, especially temperature and oxygen. Visually, when
examining springfish from these two locations, one is impressed with the relatively small head and
large body of the fish from Preston Big Spring, and on the other extreme, the large head and small
body of the fish from Mormon Spring. When standard morphometric analysis failed to elucidate
these differences adequately, a combination of measurements called "relative head size index" was
created. This i,,\dex compares the relative sizes of head and body by utilizing standard morphological
measurements (mean values) in the following manner:

Head length X head width X head depth
(standard length - head length) X body width X body depth

X 100

TAXONOMIC HISTORY. Crenichthys baileyi was originally described by Gilbert
(1893) as a subspecies of Cyprinodon macularius. The exceedingly brief description by
Gilbert was based on 11 small specimens ( < 20 mm) collected in 1891 by C. H. Merriam
and V. Bailey from "Pahranagat V alley, Nevada." The failure of Gilbert to list the specific
locality of collection in Pahranagat Valley presents a problem since three springs in the
valley, Ash, Crystal, and Hiko, harbored populations of springfish. Hiko would seem to
be eliminated as the type locality since it is somewhat removed from the river bed and
therefore the route of travel. The area near Ash Spring was frequented by travelers at that
time and probably was a stopping place for Merriam and Bailey. That Merriam and
Bailey collected fishes at Ash Spring is supported by the report of their collection of
Rhinichthys in a spring of 36.11 oC as described by Gilbert (1893). Ash spring is the only
spring of that temperature in Pahranagat Valley, and therefore, the probable type
locality of Crenichthys baileyi. Two of Gilbert' s type specimens still exist and are housed
at the California Academy of Sciences (SU 709). Jordan and Evermann (1896) considered
the fish to be specifically distinct. The genus Crenichthys was erected by Hubbs (1932)
when he described C. nevadae, the only other species of the genus, from Railroad Valley,
Nevada. Sumner and Sargent (1940), on the advice of Hubbs, then associated baileyi with

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