Munroe: Systematics of western Atlantic Symphurus 
53 
usually 52-54 in S. marginatus ), and in its stockier 
body with its greatest depth in the anterior one-third 
of the body (vs. a more elongate body with relatively 
uniform depth throughout its length and greatest 
depth near the body midpoint in S. marginatus). 
Symphurus ginsburgi can easily be distinguished 
from S. nigrescens by modal differences in dorsal-fin 
rays (87-95 vs. 82-92, usually 84-91), anal-fin rays 
(74-81 vs. 69-79 in S. nigrescens ), and total verte- 
brae (50-52, usually 51-52 vs. 47-51, usually 48-50 
in S. nigrescens). Also, the caudal fin of S. ginsburgi 
is longer (104-148 SL, x = 123) than that of S. 
nigrescens) 76-122 SL, x=105). 
Symphurus ginsburgi is similar to the western 
North Atlantic S. pusillus in body coloration, ID pat- 
tern, caudal-fin rays, peritoneum color, eye diameter, 
and relatively small size. However, S. ginsburgi dif- 
fers from S. pusillus in its higher, and mostly 
nonoverlapping, meristic features (anal-fin rays 74- 
81 vs. 71-75 in S. pusillus-, dorsal-fin rays 89-95 vs. 
83-88; total vertebrae 50-52 vs. 47-49 in S. pusillus). 
Furthermore, many S. ginsburgi usually have a dark 
brown stripe basally along the dorsal and anal fins, 
whereas S. pusillus usually lacks such stripes, in- 
stead having its fins usually yellowish with only a 
diffuse speckling of pigment along the fin rays. 
Some meristic features and ocular-side coloration 
of S. ginsburgi are also reminiscent of those found in 
S. piger, which occurs throughout the Gulf of Mexico 
and Caribbean Sea but thus far is unknown from 
waters off southern Brazil. Symphurus ginsburgi 
differs from S. piger in its higher, and mostly 
nonoverlapping, fin-ray and total vertebral counts 
(88 or fewer dorsal-fin rays, 74 or fewer anal-fin rays, 
and 49 or fewer total vertebrae in S. piger), in its 
much higher longitudinal scale count (87-94 scales 
in S. ginsburgi vs. 62-75 in S. piger), in lacking a 
fifth hypural ( present in <S. piger), in having the isth- 
mus and inner opercular linings unpigmented, and 
in having a stripe along basal margins of dorsal and 
anal fins (lightly pigmented isthmus and inner oper- 
cular linings and uniformly pigmented fins without 
basal stripe in S. piger). 
