Munroe: Systematics of western Atlantic Symphurus 
43 
has a pattern of bold, ocular-surface crossbanding 
and a pigmented spot on the scaly basal portion of 
the caudal fin, features lacking in S. stigmosus. The 
lower eye diameter in S. billykrietei is also smaller 
(98-156 HL, x =120) than that in S. stigmosus ( 128- 
171 HL, 3c =152). Smaller eye size is also evident in 
plotting ratios of ED to TKL against head length (Fig. 
20); 91% of the S. billykrietei in- 69) have a ratio less 
than 3.5, whereas 94% have a ratio less than 3.6. In 
contrast, 10/12 S. stigmosus have a ratio exceeding 3.7, 
and none have a ratio less than 3.5. The two species 
differ in eyeball shape (compare Fig. 21A with 21B). In 
S. billykrietei, the eyeball is more elongate, with its 
length slightly greater than its width, and usually there 
is a small space between the eyeballs. In contrast, the 
eyeball of S. stigmosus is more rounded, and upper- 
most aspects of the eyeballs are usually contiguous. 
Among other western Atlantic members of this 
species group, meristic features of S. billykrietei par- 
tially overlap those of S. marginatus, S. pusillus, and 
S. piger. From S. marginatus, S. billykrietei differs 
in having crossbanding on the ocular surface (lack- 
ing in S. marginatus) and in lacking the dark brown 
blotch on the caudal region of the ocular side of the 
body that characterizes S. marginatus . Symphurus 
billykrietei also has lower meristic features (dorsal- 
fin rays 89-95 vs. 93-104; anal-fin rays 76-84 vs. 
80-89, and total vertebrae 50-53, usually 51-52 vs. 
52-56, usually 52-54 in S. marginatus), and a rela- 
tively stockier and deeper body with its greatest 
Trunk length 
Figure 1 9 
Comparison of selected morphometric features of Symphurus billykrietei and S. ginsburgi (measurements in mm). (A) Snout 
length versus trunk length. (B) Head length versus trunk length. (C) Upper jaw length versus trunk length. (D) Eye diameter 
versus trunk length. (Regression equations and P-values for differences between lines appear in Table 15.) 
