Munroe: Systematics of western Atlantic Symphurus 
57 
by having one less hypural (4 vs. 5 in S. piger ) and by 
its much smaller size (70 vs. 140 mm for S. piger). 
From S. nigrescens, S. pelicanus is further differen- 
tiated in having uniformly pigmented dorsal and anal 
fins without darkly pigmented blotches (vs. dorsal 
and anal fins with pigmented blotches in many S. 
nigrescens ). 
Among other Atlantic species with a 1-3-2 ID pat- 
tern, 12 caudal-fin rays, and a black peritoneum, S. 
pelicanus, in its relatively small size, is somewhat 
similar to S. pusillus. Although dorsal-fin ray counts 
for S. pusillus partially overlap with those observed 
for S. pelicanus, these species differ in their 
nonoverlapping counts of anal-fin rays (64-70 vs. 71— 
75 in S. pusillus), S. pusillus also lacks the pepper- 
dot pattern on the blind side of the body characteris- 
tic of S. pelicanus, which has fewer longitudinal scales 
(62-70 vs. 77-87 in S. pusillus) and fewer total verte- 
brae (43-46 vs. 47^49 in S. pusillus). The isthmus and 
inner opercular linings in S. pusillus are unpigmented 
(vs. speckled with melanophores in S. pelicanus). 
The pattern of pepper-dots on the blind side of the 
body in S. pelicanus is reminiscent of that found in 
some specimens of S. arawak. However, S. pelicanus 
is easily recognized from S. arawak by its black peri- 
toneum (vs. unpigmented in S. arawak), relatively 
uniform ocular-side coloration (some S. arawak have 
darkened caudal blotch), and differences in meristic 
features (see Tables 4-9). Salient differences between 
these species are discussed in more detail in the 
“Comparisons” section of the account for S. arawak. 
Meristic features, adult sizes, and depth of occur- 
rence of S. pelicanus overlap completely with those 
of S. parvus and there are also partial overlaps with 
some meristic features for S. ommaspilus. The most 
obvious distinctions between S. pelicanus and these 
other species occur in their pigmentation patterns, 
namely peritoneum color (black in S. pelicanus vs. 
unpigmented in these others), absence of a pepper- 
dot pattern of pigment spots on the blind surface of 
S. parvus and S. ommaspilus (present in S. pelicanus), 
and the absence in S. pelicanus of a blotch on the 
ocular-side caudal region of the body (well-developed 
in S. parvus) or absence of spots on the dorsal and 
anal fins (present in S. ommaspilus). Symphurus 
pelicanus is also distinguished from both species by 
its caudal-fin ray count ( 12 vs. 10 in S. parvus and S. 
ommaspilus), in lacking a pupillary operculum and 
membrane ostia (both well developed in S. parvus 
and S. ommaspilus), and by differences in ID pat- 
tern (1-3-2 vs. 1-4-2 in S. ommaspilus, and 1-4-2 or 
1-5-2 in S. parvus). Symphurus pelicanus also has a 
longer caudal fin and more slender body than these 
other species. 
Of all species in the genus, S. pelicanus is most 
similar to the eastern Pacific S. gorgonae. Both have 
12 caudal-fin rays, a black peritoneum, and pepper- 
dots on the blind side of the body. However, S. 
pelicanus differs from S. gorgonae primarily in its 
modally lower counts (dorsal-fin rays 77-85, usually 
78-83 vs. 80-89, usually 82-88; anal-fin rays 64-70 
vs. 63-74, usually 68-74 in S. gorgonae; and total 
vertebrae 43-46, usually 45-46 vs. 46-49, usually 
46-48 in S. gorgonae). All other eastern Pacific 
Symphurus have fin-ray and vertebral counts exceed- 
ing those of S. pelicanus. 
