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1 <br />taxonomy continues to evolve. Most recently, Hinckley and DeMarais (2000} suggested <br />elevating Gila robusta grahami to Gila nigra. Recognition of specific status for robusta <br />' subspecies, as has also occurred for Gila robusta seminttda (now = Gila seminuda) and <br />Gila robusta elegans (now = Gila elegans), has significant implications for management, <br />but will not be further addressed by this report (see Table 4 for currently recognized <br />Colorado River Basin Gila species). The specific name robusta is from "robustus" <br />' meaning stout (La Rivers 1994). <br />' i <br />b <br /> Table 4 Currently reco spec <br />es. _ <br />~izal Colorado River Basin Gila species and su <br /> I ann Name Comtnon Name <br /> ~. eyp}~ humpback chub <br />e G. elegans bonytail <br /> G. intermedia Gila chub <br /> G. nigra'~ <br />robusta jordani <br />G headwater chub <br />Pahranagat roundtail chub <br /> . <br />G. robusta robusta Colorado River roundtail chub <br /> G semirtuda Virgin River roundtail chub <br />' 'Recently recommended for elevation to specific status (from G. robusta graham~~ <br />Physical description-Descriptive information presented below is summarized <br />' from Jordan and Evermann (1896), EIIis (1914), Hinckley (1973), Snyder (1981), <br />Douglas et al. (1989), Sublette et al. (1990), Baxter and Stone (1995), Sigler and Sigler <br />(199b), Douglas et al. (1998), and others noted in the text. No single morphologic <br />character or meristic count can be used for accurate identification of G. robusta because <br />' the species is highly variable in most traits. However, a suite of characters has been used <br />to reliably identify most specimens (Douglas et al. 1989,1998, McElroy et al. 1997). <br />Like other Gila, body form of roundtail chub is elongated and fusiform. Roundtail chub <br />may have a somewhat flattened head, but are lacking the nuchal hump found in <br />humpback chub and, to some extent, bonytail. The mouth is large, sub-terminal, and <br />' associated with an acute snout. Eyes are small, low, and anteriorly placed on the head. <br />Fins are generally large. Pectorals are pointed (fin rays' 14-15[12-17]); dorsal fin weakly <br />' 'Counts (fin ray, vertebrae, dentition, etc.) are presented with the most commonly reported count outside <br />the brackets and the range of values encountered in the literature inside the brackets. <br />Final Report September 21h12 17 <br /> <br />