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DESCRIPTION
<br />The woundfin is the most silvery of all American minnows (Miller and
<br />Hubbs, 1960), reflecting blue in bright sunlight. The only breeding
<br />color noted has been a wash of light-yellow at the bases of the pectoral
<br />and pelvic fins. The species rarely achieves a standard length of more
<br />than 75 millimeters (mm), but occasional specimens, usually females,
<br />exceed 100 mm (unpublished data).
<br />The head and belly of the woundfin are flattened, and the overall aspect
<br />of the fish is one of an anteriorly-depressed, streamlined torpedo. This
<br />body shape is characteristic of fish inhabiting swift, shallow, sand-
<br />bottomed streams. Other adaptations to this type of habitat that co-
<br />habiting fish species share with Pla~opterus include expansive, falcate
<br />fins, barbels on the lips, reduced eyes, and extensive sensory buds,
<br />presumably chemoreceptors, on the lower part of the head (the gular
<br />region in Plagopterus), (Snyder, 1915), and along the leading pectoral
<br />fin-rays (Moore, 1950; Branson, 1963, 1966; Cross, 1967). Woundfin are
<br />essentially scaleless, with the exception of small plates of bone situated
<br />in the leathery skin, especially near the nape. Adaptive features unique
<br />to the woundfin include a modification of the two anterior fin-rays of
<br />the dorsal fin into enlarged, elongated, and solidified spinose rays,
<br />the second of which fits into a groove in the first. Also, the branched
<br />pelvic rays are thickened and spinelike on the basal half to three
<br />fourths of each ray. A further specialization in Plagopterus is a spinelike
<br />development near the base of the first few pectoral fin-rays.
<br />TAXONOMIC STATUS
<br />The woundfin is considered the most highly specialized species in the r~
<br />cyprinid tribe Plagopterini, subfamily Leuciscinae (Miller and Hubbs, ~,
<br />1960). This unique tribe is composed of three genera, two of which, Meda
<br />and Pla~opterus, are monotypic, and the third, Lepidomeda, is composed
<br />of four species, one with two subspecies. The present taxonomic ranking
<br />of the group was initiated by Hubbs (1955), and is generally accepted.
<br />The uniqueness of this compact group of fishes has always impressed
<br />ichthyologists. Cope (1874) erected a full subfamily, the Flagopterinae,
<br />for the genera, and this was widely followed (Jordan and Gilbert, 1883;
<br />Jordan and Evermann, 1896). Jordan, et al. (1930) even erected a separate
<br />family, the Medidae, for the group, an action followed only by Tanner
<br />(1936). The entire taxa is endemic to the lower basin of the Colorado
<br />River and its ancestral tributary, the White River.
<br />HISTORIC DISTRIBUTION
<br />
<br />On the basis of early records, the original range of woundfin extended
<br />from near the junction of the Salt and Verde rivers at Tempe, Arizona, to
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<br />the mouth of the Gila River at Yuma (Gilbert and Scofield, 1898); likely
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