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Fishery Bulletin 96(1 ), 1998 
compare Fig. 3, D and E), lacks a black spot on the 
ocular-side opercle, has an unpigmented or only 
lightly pigmented inner opercular lining on the blind 
side, and when present on the body, crossbands are 
faint and narrow, whereas S. tessellatus has a bold 
pattern of wide crossbands, a heavily pigmented in- 
ner opercular lining, and a well-developed, black 
opercular spot. Other distinctions between these spe- 
cies include the absence of scales on blind sides of 
dorsal- and anal-fin rays of S. civitatium (present in 
S. tessellatus larger than about 60 mm), usually fewer 
vertebrae (total vertebrae 47-49 versus 50-53 in S. 
tessellatus), and modally lower meristic features: 
dorsal-fin rays 86-93 versus 91-102 (usually 93-101) 
in S. tessellatus-, anal-fin rays 70-78 versus 77-86; 
scales in a longitudinal series 66-83 versus 81-96. 
Symphurus civitatium is similar to S. oculellus 
with respect to small eye size, and presence of a fleshy 
ridge on the ocular-side lower jaw. It differs from this 
species, however, in its much lower counts (46-50 
total vertebrae versus 52-55 in S. oculellus-, dorsal- 
fin rays 86-93 versus 97-106; anal-fin rays 70-78 
versus 81-89) and pigmentation pattern. Symphurus 
civitatium has a relatively uniform body coloration 
with faint crossbands, uniformly pigmented fins 
without blotches and no pigment spot on the outer 
opercle (vs. sharply contrasting crossbands, pig- 
mented blotches alternating with unpigmented ar- 
eas in dorsal and anal fins, and black spot on outer 
opercle in S. oculellus). Furthermore, inS. civitatium, 
the first dorsal-fin ray is usually located along a ver- 
tical anterior to the upper eye, whereas in S. 
oculellus, the dorsal-fin origin usually extends ante- 
riorly only to the vertical through the anterior mar- 
gin or mid-eye region of the upper eye. 
Some meristic values of S. civitatium overlap those 
of 11 other species of Atlantic tonguefishes. 
Symphurus civitatium occurs sympatrically with S. 
diomedeanus and S. plagiusa and may sometimes 
be collected with these species. Differences between 
S. civitatium and these species are discussed in the 
“Comparisons” sections for S. plagiusa and S. 
diomedeanus. Excluding differences in caudal-fin ray 
counts, there is almost complete overlap in meristic 
features between S. civitatium and the sympatric 
(but not syntopic) western North Atlantic species, S. 
urospilus. Differences between S. civitatium and S. 
urospilus are discussed in the “Comparisons” section 
in the account for S. urospilus. 
Meristic values of S. civitatium overlap those of 
five eastern Pacific species, S. atricaudus , S. melan- 
urus, S. williamsi, S. fasciolaris, and S. melasmato- 
theca, possessing either a 1-4-3 or 1-5-3 ID pattern. 
Of these, S. civitatium is most similar to S. melanurus 
in that both possess a fleshy ridge on the ocular-side 
lower jaw, and in both the first dorsal-fin ray reaches 
the vertical equal with or anterior to the anterior 
margin of the upper eye. Symphurus civitatium lacks 
a pupillary operculum (weakly developed pupillary 
operculum usually present in S. melanurus), has 
fewer longitudinal scales (66-83 vs. 89-108 in S. 
melanurus), and S. civitatium has an unpigmented 
or only lightly pigmented inner lining on the blind- 
side opercle (vs. darkly pigmented inner lining on 
blind-side opercle in S. melanurus). 
