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Fishery Bulletin 1 13(4) 
Principal component 1 
Principal component 1 
Figure 3 
Scatterplot of principal components 1 and 2 from principal component analysis of 32 linear morphometric measurements 
(A) for all specimens of Sebastes mystinus, blue rockfish (black circles), and S. diaconus new species, deacon rockfish (gray 
squares), examined for this study (n = 120) and (B) for only specimens over 150 mm SL (S. mystinus, n= 37, and S. diaconus, 
n= 36). Ellipses represent 95% confidence intervals. The white circle indicates the lectotype of S. mystinus, USNM 27085, 
and the gray cross indicates the holotype of S. diaconus, CAS 236653. 
the DFA and yielded a linear equation permitting 
100% correct reclassification of 73 adult specimens 
(Fig 5B). The coefficients for head length (HL) and 
prepelvic fin length increased substantially in the 
discriminant function that was restricted to indi- 
viduals over 150 mm SL, in comparison with the 
function including specimens of all sizes (Table 2). 
Between-group comparison of type-II regres- 
sions of the untransformed measurements with the 
highest loadings on size-standardized PCI against 
SL indicated significantly different slopes for the 
lengths of anal-fin spine I (P<0.001) and anal-fin 
spine II (P=0.002), for symphyseal knob length 
(P<0.001), and for ventral caudal peduncle length 
(P=0.003). Linear regressions of these 4 variables 
against SL illustrate the differences in slope (Fig. 
6, A-D). It appears that the 2 species are morpho- 
metrically similar at smaller sizes yet differentiate 
interspecifically as they age, with the symphyseal 
knob length (Fig. 6A) and the lengths of the anal- 
fin spines (Fig. 6, B and C) diverging substantially 
in specimens over 150 mm SL. Ventral caudal pe- 
duncle length diverges less pronouncedly (Fig 6D). 
On the basis of the morphometric differences 
discovered in this study, the differences in body 
coloration, and the correspondence of the morpho- 
types with previously identified genetic groups, we 
recognize the 2 genetic lineages within the previous 
concept of S. mystinus as full species. We describe 
S. diaconus, or the type-1 or blue-sided form, as 
new; we restrict S. mystinus to the type-2 or blue- 
blotched form; and we redescribe the latter species 
and designate a lectotype and paralectotypes. 
Figure 4 
Scree plot of percent variance explained by principal compo- 
nents of morphometric measurements (A) for all specimens 
of Sebastes mystinus (blue rockfish) and S. diaconus (deacon 
rockfish) combined (n=120) and (B) for only specimens over 
150 mm SL (S. mystinus, n=37, and S. diaconus, n= 36). 
