7406

• UCREFRP Catalog Number: 7406
• Author: Bestgen, K. R.
• Title: Status Review of the Razorback Sucker,
• USFW Year: 1990.
• Copyright Material: NO

Eastman (1977, 1980) described the pharyngeal bones, teeth,
and caudal skeleton of the razorback sucker. Like most other
catostomid genera, Xvrauchen is characterized by an intermediate
number of moderately compressed pharyngeal teeth arranged in a
comb-like fashion, presumably an adaption benthic feeding
(Eastman 1977). The razorback sucker caudal skeleton is
relatively heavily ossified, and caudal rays are thickened and
foreshortened. Eastman (1980) presumed that these features were
adaptions to the strong currents present in rivers occupied by
this species.
No studies have been attempted to determine if intraspecific
variation occurred in the formerly extensive geographic range of
the razorback sucker. A qualitative comparison of the few
meristic data presented by Hubbs and Miller (1953) indicated that
Upper Colorado River and Gila River specimens were similar.
DIBTRIHIITION AND BTATIIB
The 1922 Colorado River Compact divided the Colorado River
Basin into upper (UCRB} and lower (LCRB) portions (Fig. 1) at Lee
Ferry, Arizona (review by Carlson and Muth 1989). This provides
a convenient point of division for discussion of status and
biology of the razorback sucker.
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