Munroe: Systematics of western Atlantic Symphurus 
61 
■5 
Cl. 
<L> 
TD 
73 
O 
CO 
100 120 140 
B 350 
300 
=1 
I 
250 
200 
20 40 60 80 100 120 140 
Standard length 
Figure 30 
Comparisons of selected morphometric features for 
Symphurus pusillus and S. piger. (A) Body depth (thou- 
sandths of standard length) versus standard length (mm). 
(B) Head width (thousandths of standard length) versus 
standard length (mm). 
darkly pigmented blotches (if blotches are present, 
they are small and only lightly pigmented) or lack 
any noticeably dark pigment streaks on the fin rays. 
In contrast, S. nigrescens usually has quite colorful 
dorsal and anal fins featuring a series of alternating 
dark blotches and unpigmented areas entirely 
throughout these fins, or if pigmented blotches are 
not present, then the individual fin rays throughout 
the entire dorsal and anal fins are streaked with dark 
16 
CTJ 
T3 
3 
03 
U 
+ 
14 - 
+ 
+ 
12 - 
+ + 
+ + 
+ 
+ 
10 - 
8 - 
+ 
"1 
6 1 L 
30 50 70 
B nigrescens 
+ pusillus 
_J l 
90 110 
Standard length 
Figure 3 1 
Comparison of caudal-fin length (expressed in percent stan- 
dard length) versus standard length for Symphurus pusillus 
(western Atlantic) and S. nigrescens (eastern Atlantic). 
pigment over their entire lengths. Symphurus pusillus 
is also a smaller species reaching maximum sizes of 
only ca. 77 mm and maturing at sizes as small as 45 
mm, whereas, S. nigrescens attains larger sizes (to 117 
mm and not reaching maturity until 70 mm or larger). 
Symphurus pusillus has some morphological fea- 
tures similar to those observed in the western At- 
lantic S. pelicanus and S. rhytisma. Differences be- 
tween these species are substantial and discussed 
in the “Comparisons” sections in accounts for S. 
rhytisma and S. pusillus. 
Some meristic features and ocular-side coloration 
of S. pusillus are similar to those found in S. 
billykrietei, S. ginsburgi, and S. stigmosus. In fact, 
throughout its range S. pusillus co-occurs with, but 
is not usually syntopic with, S. billykrietei (only one 
lot in VIMS collection (1905) taken at 40°N and 
233 m, and coincidentally, the deepest known cap- 
ture for S. pusillus, contained both species) and S. 
stigmosus. Symphurus pusillus differs from all three 
species in its generally lower, mostly nonoverlapping, 
meristic features (dorsal-fin rays 83-88 vs. 87-95, 
anal-fin rays 71-75 vs. 74-84, and total vertebrae 
47-49 vs. 50-53 in the others). Other differences be- 
tween S. pusillus and these species are discussed in 
the “Comparisons” sections for S. ginsburgi, S. 
billykrietei, and S. stigmosus, respectively. 
