7017

• UCREFRP Catalog Number: 7017
• Author: Starnes, W. C.
• Title: Colorado River Basin
• USFW Year: 1989.
• Copyright Material: NO

introgressed populations derived from robusta and
intermedia. Concludes that lower basin chubs demonstrate a
lack of ecotypy and show no patterns consistent with
interspecific "intergradation" but subspecific
intergradation was apparent between subspecies grahami and
robusta. Discusses probable closest relationships of
intermedia with chub species to the south in the Mexican
Plateau region as opposed to robusta.
1977. Ecology Consultants, Inc. An indexed, annotated
bibliography of the endangered and threatened fishes of the
upper Colorado River system. U.S. Fish & Wildlf. Serv.
FWS/OBS-77/61. 169 p.
Provides annotated references, including taxonomic, to many
works published prior to 1977 but has a decidely upper basin
focus as the title suggests. A valuable guide to works not
published in the primary literature.
1977. Joseph, T.W., J.A. Sinning, R.J. Behnke, and P.B. Holden.
An evaluation of the status, life history, and habitat
requirements of endangered and threatened fishes of the
upper Colorado River system. U.S. Fish & Wildlf. Serv.
FWS/OBS-77/62. 184 p.
Contains a thorough discussion of the Gila complex" in light
of "modern" species concepts, but basically subscribing to a
biological or "genetic" species concept (now no longer
considered modern), and pointing out the importance of
knowing what taxa are involved when managing endangered
species. Reiterates the view of Holden and Stahnaker (1970)
that the real problems lie with determinations of the
taxonomic status of G. cyoha versus G. elegans with the
distinctness of elegans from robusta being non-
problematical. Regards cypha and elegans as "valid" species
and poses the question as to whether these forms may be
hybridizing extensively in some areas and maintaining
integrity in others, but also raises the question, based on
morphologically intermediate "intergrades", if cypha should
be considered a subspecies of elegans. Points out the need
for extensive studies of hybridization among the species.
Also briefly recapitulates the taxonomic history of each
taxon.
1977. Suttkus, R.D., and G.H. Clemmer. The humpback chub, Gila
cypha, in the Grand Canyon area of the Colorado River. Occ.
Pap. Tulane Univ. Mus. Nat. Hist. 1. 30 p.
Contains an extremely detailed description and analysis of
variation of G. cypha at growth stages ranging from small
juveniles to adults based on Grand Canyon area specimens and
compares these with a small number of supposed juveniles of
11