44 
Fishery Bulletin 96(1), 1998 
_c 
a 
C 
g 
cd 
Oh 
5 
4 
3 
2 
A A 
AA 
« A 
A A 
AAA* AAA 
A AA AAAA A AAA 
A A AA A A 
A AAA A A 
AA A A A 
A AA A 
A A A 
■ 
A 
A 
A A 
AA 
A 
AA 
A 
A 
A 
• S. gins bur gi 
a S. billykrietei 
■ S. stigmosus 
185 200 215 230 245 260 
Head length 
Figure 20 
Relation of the ratio of eye diameter to trunk length, plotted against head length (in 
thousandths of SL) for Symphurus billykrietei , S. stigmosus, and S. ginsburgi. 
depth in the anterior one-third (vs. a more elongate 
body with more uniform body depth and greatest 
depth at body midpoint in S. marginatus). 
The ocular-side coloration in S. billykrietei is very 
similar to that observed in the sympatric S. pusillus, 
but differs from this species in its higher and mostly 
nonoverlapping meristic features (dorsal-fin rays BO- 
SS vs. 83-88 in S. pusillus; anal-fin rays 76-84 vs. 
71-75; and 50-53 total vertebrae vs. 47-49 in S. 
pusillus). The two species also differ in that S. 
billykrietei has a dark brown stripe along basal mar- 
gins of the dorsal and anal fins, whereas these fins 
in S. pusillus lack a basal stripe, instead having only 
a diffuse speckling of brown pigment, and, on their 
distal margins, often a yellowish color. 
Some meristic features and aspects of ocular-side 
coloration of S. billykrietei are similar to those in S. 
piger, a deepwater species widespread in the Gulf of 
Mexico and Caribbean Sea. Symphurus billykrietei 
differs from S', piger in lacking a fifth hypural 
(present in S. piger), in its more elongate body (com- 
pare Figs. 16 and 34), in its more numerous fin rays 
(89-95 dorsal-fin rays and 76-84 anal-fin rays in S. 
billykrietei vs. 88 or fewer dorsal-fin rays and 74 or 
fewer anal-fin rays in S. piger), total vertebral counts 
(50-53 in S. billykrietei vs. 49 or fewer in S. piger), 
and in its longitudinal scale count (80-100 in S. 
billykrietei vs. 62-75 in S. piger). 
Symphurus billykrietei can be distinguished from 
the eastern Atlantic S. nigrescens (which also pos- 
Figure 21 
Schematic illustration indicating relative shapes 
and positions of eyeballs within the orbital sac 
for three species of western Atlantic Symphurus . 
(A) Round, nearly contiguous eyes of S. stig- 
mosus. (B) Elongate, noncontiguous eyes of S. 
billykrietei and S. ginsburgi. 
sesses a 1-3-2 ID pattern, 12 caudal-fin rays, and 
black peritoneum) by modal differences in meristic 
features (dorsal-fin rays 89-95 vs. 82-92, usually 84- 
91 in S. nigrescens; anal-fin rays 76—84 vs. 69-79 in S. 
nigrescens; and 50-53, usually 51-52, total vertebrae 
vs. 47-51, usually 48—50, vertebrae in S. nigrescens). 
This species also has a longer caudal fin (100-147 SL, 
x =121) than that of S. nigrescens (76— 122 SL, 5; =105). 
