Munroe: Systematics of western Atlantic Symphurus 
97 
and anal fins. In his description of S. sumptuosus, 
Chabanaud failed to compare his new species with 
previously described western Atlantic tonguefishes, 
even S. diomedeanus, which also possesses 10 cau- 
dal-fin rays and spotted dorsal and anal fins. 
Ginsburg (1951) recognized that S. sumptuosus was 
conspeciflc with S. diomedeanus, pointing out that 
the holotype of S. sumptuosus agreed with S. 
diomedeanus in the number of caudal-, dorsal-, and 
anal-fin rays and scales in a longitudinal series and 
that both nominal species possessed a series of spots 
on the dorsal and anal fins. Additional similarities 
between the holotype of S. sumptuosus and the holo- 
type and other specimens of S. diomedeanus were 
found in the present study. These include the num- 
ber of total vertebrae (50 in S. sumptuosus vs. 47-50 
in S. diomedeanus), and ID pattern (1-4-3, both spe- 
cies). Both nominal species also possess a pupillary 
operculum and an unpigmented peritoneum, and 
have similar morphometric features (see Table 27). I 
agree with Ginsburg that S. sumptuosus is a syn- 
onym of S. diomedeanus . 
In that same paper, Ginsburg (1951) described 
another nominal species, S. pterospilotus, from one 
specimen collected off Uruguay. Ginsburg thought 
this nominal species was distinct from other conge- 
ners because of its unique combination of a spot on 
the caudal fin, a series of spots on the dorsal and 
anal fins, and its 11 caudal-fin rays. He noted that, 
except for the number of caudal-fin rays, all other 
counts for this specimen exceeded those for S. 
urospilus, the only other western North Atlantic spe- 
cies with 11 caudal-fin rays and a spotted caudal fin. 
He thus considered the specimen to represent a dis- 
tinct taxon. In further comparisons of his new spe- 
cies with other western Atlantic Symphurus, Gins- 
burg noted that fin-ray and scale counts for S. 
pterospilotus overlapped with those for S. diomedeanus. 
However, given the presence of a caudal-fin spot and 
differences in number of caudal-fin rays ( 1 1 vs. 10 in S. 
diomedeanus), he concluded that it was appropriate to 
describe S. pterospilotus as a distinct species. 
Menezes and Benvegnu (1976) evaluated the sta- 
tus of all nominal tonguefish species from South 
American waters having 10 or 11 caudal-fin rays and 
spotted dorsal and anal fins. They noted that occa- 
sional specimens of S. diomedeanus have a partial 
or complete spot on the caudal fin and that some 
specimens have either 9 or 11 caudal-fin rays, in- 
stead of the 10 caudal-fin rays typical for this spe- 
cies. Menezes and Benvegnu thus noted that the 
characters Ginsburg used to discriminate S. ptero- 
spilotus from S. diomedeanus , namely the combina- 
tion of 11 caudal-fin rays and a spot on the caudal 
fin in addition to spots on the posterior dorsal and 
anal fins, were not diagnostic of a new species, be- 
cause they were also found in samples of S. diomede- 
anus, which they examined. Menezes and Benvegnu 
concluded, therefore, that S. pterospilotus Ginsburg 
is based on a specimen of S. diomedeanus featuring 
an unusual combination of meristic and pigmenta- 
tion features. 
Additional evidence supporting placement of S. 
pterospilotus in the synonymy of S. diomedeanus was 
found in this study. Although most specimens of S. 
diomedeanus possess 10 caudal-fin rays, specimens 
with 11 caudal-fin rays do occur (5/196 of S. 
diomedeanus examined, Table 3), albeit rarely. Also, 
the 49 vertebrae of the holotype of S. pterospilotus 
fall within the range of vertebrae in S. diomedeanus 
(Table 6). The two nominal species share the same 
ID pattern (1-4-3), both possess a pupillary opercu- 
lum and unpigmented peritoneum, and both have 
similar morphometric features (see Table 27). On the 
basis of available evidence, I agree with Menezes and 
Benvegnu ( 1976) that S. pterospilotus Ginsburg is a 
junior synonym of S. diomedeanus, which is the only 
species occurring throughout the western Atlantic 
with the combination of 10 (rarely 9 or 11) caudal- 
fin rays and a series of spots on the posterior regions 
of the dorsal and anal fins ( occasional specimens also 
with a spot on the caudal fin in combination with 
other spots on the posterior dorsal and anal fins). 
Comparisons Symphurus diomedeanus is similar 
in ID pattern, body shape, overall size, and has mer- 
istic features that overlap, at least partially, those of 
several western Atlantic tonguefishes also possess- 
ing the 1-4-3 ID pattern, including S. plagiusa, S. 
urospilus, S. civitatium, S. plagusia, S. tessellatus, 
S. oeulellus , and S. caribbeanus . Symphurus 
diomedeanus differs from these species, except S. 
plagiusa, in caudal-fin ray count (10 vs. 11 in S. 
urospilus, 12 in the others), and in modal counts for 
total vertebrae and dorsal- and anal-fin rays (see 
Tables 4-6). 
In overall size and similarity of meristic features, 
S. diomedeanus most resembles S. plagiusa. Like S. 
plagiusa, S. diomedeanus has 10 caudal-fin rays and 
an unpigmented peritoneum but differs from this 
species in possessing a well-developed pupillary oper- 
culum and a variable number of conspicuous black 
spots on the posterior dorsal and anal fins (both fea- 
tures absent in S. plagiusa). Symphurus diome- 
deanus lacks the small ctenoid scales on blind sides 
of the posterior rays of the dorsal and anal fins, the 
fleshy ridge on the ocular-side lower jaw, and black 
spot on the dorsal portion of the ocular-side opercle 
usually present in S. plagiusa. Symphurus diome- 
deanus is also distinct from S. plagiusa in having an 
