Munroe: Systematics of western Atlantic Symphurus 
123 
Comparisons Among western Atlantic tongue- 
fishes, <S. caribbeanus most closely resembles other 
members of the S. plagusia complex (Munroe, 1991) 
and occurs sympatrically with S. plagusia and juve- 
nile and subadult S. tessellatus. Meristic values of 
S. caribbeanus overlap almost completely with those 
of S. plagusia. The two species can be distinguished, 
however, by the absence, in S. caribbeanus, of the 
fleshy ridge on the ocular-side lower jaw (present in 
S. plagusia; see Fig. 3, D and E). Symphurus carib- 
beanus usually has numerous, prominent crossbands 
on the body, and vertical fins have an alternating 
series of blotches and unpigmented areas, which are 
especially well developed posteriorly. In contrast, S. 
plagusia is generally uniformly colored with only 
slight evidence of crossbanding, and the fins are uni- 
formly colored. Symphurus caribbeanus has a more 
pointed snout with a distance between upper eye and 
dorsal-fin base usually slightly less than twice the 
eye diameter, versus a squarish snout with distance 
from upper eye to dorsal-fin base usually larger than 
twice the eye diameter in S. plagusia (compare Figs. 
54 and 60). The body shape of S. caribbeanus is 
rounded, with a pronounced taper posterior to dor- 
sal-fin rays 25-35 (vs. somewhat elongate in S. 
plagusia with a more gradual taper). Additionally, S. 
caribbeanus has a slightly larger eye (8.2-11% HL, 
usually 9.0-10.0% HL) in comparison with that of S. 
plagusia (usually 7.0-9.0%> HL). 
Symphurus tessellatus, especially juveniles and 
small adults (to about 150 mm), are superficially 
similar in overall body shape, relative eye size, and 
body pigmentation (crossbanding) to S. caribbeanus. 
However, S. caribbeanus is easily distinguished from 
S. tessellatus in lacking the black spot on the outer 
surface of the ocular-side opercle and scales on blind- 
side dorsal and anal fins (both present in S. 
tessellatus), and S. tessellatus has the posterior dor- 
sal and anal fins, as well as the caudal fin, uniformly 
darkly pigmented without alternating blotches and 
unpigmented areas and often has black pigment 
patches on the blind side of the body. In contrast, the 
posterior regions of the vertical fins of S. caribbean us 
have alternating dark blotches and unpigmented 
areas without a progressive darkening in coloration 
posteriorly in these fins, and the blind side of the 
body lacks black pigment patches. Symphurus 
caribbeanus also has modally lower counts than S. 
tessellatus (total vertebrae 49-50 vs. 50-53 in S. 
tessellatus; dorsal-fin rays 89-96 vs. 91-102; anal- 
fin rays 74-80 vs. 77-86; 78-89 vs. 81-96 longitudi- 
nal scales). 
Symphurus caribbeanus differs considerably from 
S. civitatium and S. oculellus. There is almost com- 
plete overlap in several meristic features between S. 
civitatium and S. caribbeanus , however, S. civitatium 
has a fleshy ridge on the ocular-side lower jaw (ab- 
sent in S. caribbeanus; see Fig. 3, D and E) and has 
lower modal counts for total vertebrae (47-49 vs. 49- 
50 in <S. caribbeanus), dorsal-fin rays (86-93 vs. 89— 
96), and anal-fin rays (70-78 vs. 74-80). Symphurus 
caribbeanus has numerous, well-developed cross- 
bands and vertical fins with an alternating series of 
blotches and unpigmented areas in individuals of 
both sexes. In contrast, S. civitatium also has nar- 
row crossbands with uniformly colored fins (becom- 
ing progressively darker in posterior portions of sexu- 
ally mature males). Sytnphurus caribbeanus also has 
a more pointed snout with only a narrow space be- 
tween the upper eye and dorsal-fin base (vs. square 
snout with space between upper eye and dorsal-fin 
base usually greater than twice the eye diameter in 
S. civitatium; compare Figs. 54 and 56). 
From S. caribbeanus, S. oculellus differs in hav- 
ing much higher meristic values (52-55 total verte- 
brae vs. 48-51 in S. caribbeanus; 97-106 dorsal-fin 
rays vs. 89-96; 81-89 anal-fin rays vs. 74-80 in S. 
caribbeanus). Symphurus caribbeanus lacks the 
black blotch on the ocular-side opercle and fleshy 
ridge on the ocular-side lower jaw (see Fig. 3, D and 
E) present in S. oculellus. Symphurus oculellus also 
has a deeper body (231-297 SL, x=274) compared 
with that of S. caribbeanus (277-320 SL, x=301). 
Meristic values of S. caribbeanus overlap with 
those of 11 other Atlantic species of Symphurus. 
Symphurus caribbeanus is readily distinguished from 
seven deepwater Atlantic species with similar mer- 
istic values (S. marginatus, S. piger and S. stigmosus, 
occurring in the Gulf of Mexico and Caribbean Sea, 
two western North Atlantic species, S. pusillus and S. 
billykrietei, the western South Atlantic S. ginsburgi, 
and the eastern Atlantic S. nigrescens) in ID pattern 
( 1-4-3 vs. 1-3-2 in the others) and peritoneal pigmenta- 
tion (unpigmented vs. dark black, visible through both 
sides of abdominal wall in the others). 
Three shallow-water, western Atlantic species, S. 
diomedeanus, which occurs sympatrically with S. 
caribbeanus, and the allopatric S. plagiusa and S. 
urospilus, have meristic features similar to those of 
S. caribbeanus. Symphurus caribbeanus differs from 
these in caudal-fin ray count (12 vs. 10 in S. 
diomedeanus and S. plagiusa, 11 in S. urospilus) and 
pigmentation of the vertical fins. Other differences 
between S. caribbeanus and these species are dis- 
cussed in the “Comparisons” sections in respective 
species accounts. 
Meristic values of S. caribbeanus overlap with 
those of six eastern Pacific species possessing either 
a 1-4-3 or 1-5-3 ID pattern. Symphurus caribbeanus 
differs from S. leei, S. atricaudus, S. melanurus, S. 
