7258

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

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morphometric variables (Blacklith and Reyment, 1971

Humphries et

&1., 19(1).

~nlike loadings for PC1, only subsets of the 31 distance measures

had significant scores on PC2 and PC3 (Table 1).

Significant

loadings o~ PC2 were bipolar, scores having both positive and

negative values.

Two general body regions were involved (Table

1; fig. 3).

Four head measurements appeared diagnostic: mouth

length

(Measurement No.2; 0.37); pre-orbital length (No. 14;

o. 63 ); ant e r i 0 r m 0 S t cd g e 0 for bit too c c i pu'irn ( No.4; O. 32 ); and

snout to occiput (No.5; 0.33).

The other significant measure-

ments involved the depth of the mid-region of the body as defined

by the pelvic and medi~n fins: pelvic fin origin to posteriormost

pe.rt of dorsal fin base (No. 26; -0.34); pelvic fin base to

dorsal fin base origin (No. 23; -0.40); dorsal fin base origin

to anal fin base origin (No. 25; -0.35); and posteriormost p,'-\rt

of dorsal fin base to anal fin base origin (No. 28; -0.34). The

anal fin base (No. 10) was related to the truss composed of these

mid-body measurements, loading significantly with the same sign

on PC2 (-0.37).

Although the least depth of the caudal peduncle

(No. 12) has been considered an important differentiating

char~cter (Smith et al., 1979), its loading was not signifi~ant

in the PCA.

Three characters had significant loadings on PC3, each involving

shape of the he,~d region (Table 1; Fig. 3): mouth length (No.2;

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