7258

• UCREFRP Catalog Number: 7258
• Author: Rosenfeld, M. J.
• Title: Morphometry in Chubs of the Genus
• USFW Year: 1986.
• Copyright Material: NO

large nuchal hump.

Another possibility is that the "bony tail"

chub is actually conspecific with the "humpback" chub.

PCA results on Blackrocks fish indicates that the DFA equation

for "humpback" chubs may not be constructed from the entire

within-species range of variation.

Discrimtnant function

analysis (DFA) is an ~ priori method, requiring designation of

group affiliations before mathematical definition of groups.

Consequently, its usage must be restricted to those cases for

which lineages- (e.g., species) are known '.dTH' confidence. Very

little is currently known about chub taxonomy. If a lineage such

as t.f1e "humpback" one is arbitrarily subdivided, DFA will

quantify each division differently.

Ignorant use of DFA could

become teleological if each arbitrary division were to be

considered a species.

Without knowledge on population genetics,

we cannot distinguish between small samples taken from different

parts of the intraspecific variational range or from different

phylogenetic lineages.

Highly-variable lineages occurring over

large geographic distances may also require DFA's specific to

restricted regions; what adequately defines groups in one area

may not work as well in another location.

The morphologies of fish from nearby Westwater Canyon were more

variable.

Some fish sorted as "roundtail" chubs and others as

"humpbaCk" chubs.

Individuals that plotted into the [ap separa-

ting the Blackrocks groupings may have been hybrids between the

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