94 
Fishery Bulletin 96( 1 ), 1998 
one-third of body generally with more intense pig- 
mentation than anterior fin rays, becoming variably 
dusky, dark brown, or occasionally black. Fin rays in 
posterior one-third of dorsal and anal fins usually with 
1-5 conspicuous, rounded, dark brown or black spots 
on each fin. Topp and Hoff (1972) presented more 
detailed discussion of frequency of occurrence and 
location of spots on fins of this species in Florida wa- 
ters. Spots on fin rays and membranes situated about 
midway between bases and distal tips of fin rays. 
Spots on dorsal and anal fins usually unequal in 
number and slightly offset from those in opposing 
fin. Posteriormost spot in each fin usually short dis- 
tance anterior to base of caudal fin. Fin spots usu- 
ally moderately or sharply contrasting to general fin 
pigmentation; occasionally first 1-3 spots poorly de- 
fined; spots on more posterior regions of fins gener- 
ally with more well-defined, rounded shape. Mela- 
nistic specimens with fins uniformly darkly pig- 
mented through most of length with fin spots present, 
although sometimes barely perceptible against back- 
ground coloration. Specimens from light-colored sub- 
strates occasionally with fin spots barely perceptible 
without magnification. Caudal fin uniformly dark 
brown or black along length of fin; unusual speci- 
mens with single, rounded, nonocellated spot eccen- 
trically placed on distal one-third of caudal fin. 
Size and sexual maturity (Fig. 9DJ Symphurus 
diomedeanus is a relatively large species, with a 
maximum reported size of 207 mm for a specimen 
collected off North Carolina (Ginsburg, 1951). This 
is the third largest of the Atlantic symphurine 
tonguefishes (only S. jenynsi and S. tessellatus are 
larger, see below). Males and females attain similar 
sizes. The largest specimen examined in this study 
( 183 mm) is a female, whereas the next largest speci- 
men (180 mm) is a male. Although 56 of the 324 speci- 
mens measured exceeded 150 mm, most were usu- 
ally smaller than 130 mm. Topp and Hoff (1972) re- 
ported a size range of 48-174 mm (all but one speci- 
men exceeded 100 mm), with estimated mean sizes 
of 149.1 mm for females and 146.8 mm for males, for 
S. diomedeanus collected off west Florida. 
Among 169 specimens for which size-related life 
history information was summarized, 90 were fe- 
males (85.3-183 mm) and 79 males (66.8-180 mm). 
Sexual maturation in females occurs usually between 
90 and 120 mm. The smallest mature females mea- 
sured ca. 89-107 mm, respectively. However, the 
majority of mature females (n=55) were 120-150 mm. 
Seven immature females ranged in size from 84.6 to 
119 mm. 
Of particular interest is the general scarcity of 
smaller fish in collections examined. Among 324 
specimens measured, only 20 were smaller than 100 
mm (57.9-98.3 mm). In fact, the smallest of speci- 
mens taken in benthic collections is 48 mm (Topp 
and Hoff, 1972). It seems unlikely that the absence 
of small S. diomedeanus in collections results entirely 
from selectivity of collecting gear (mostly trawls) for 
larger specimens, because specimens 75 mm and less 
of other tonguefish species are routinely taken in 
trawls. Instead, the absence of smaller size classes 
of S. diomedeanus in trawl collections may indicate 
that juveniles occupy different habitats than those 
of adults, and that these areas are not generally 
sampled, or are inaccessible to conventional trawl- 
ing gears. 
Geographic distribution (Fig. 47) Symphurus 
diomedeanus has the most extensive geographic dis- 
tribution of any western Atlantic flatfish. It occurs 
on the inner continental shelf in warm temperate 
and tropical waters from the region just north of Cape 
Hatteras, North Carolina (35°23'N ), along the south- 
eastern Atlantic coast of the United States, through 
the Gulf of Mexico and Caribbean Sea (Ginsburg, 
Figure 47 
Geographic distribution of Symphurus diomedeanus based on 
material examined (discussion of geographic distribution appears 
in species account). 
