Munroe: Systematics of western Atlantic Symphurus 
7 
Table 2 
Number of specimens with predominant interdigitation patterns (ID pattern) of dorsal pterygiophores and neural spines in 
western Atlantic species of Symphurus. 
ID Pattern 
Species 
1-2-2 
1-3-2 
1-3-3 
1-4-2 
1-4-3 
1-5-2 
1-5-3 
Other 
nebulosus 
22 

— 
— 
— 
— 
— 
5 
arawak 
1 
35 
1 
— 
— 
— 
— 
4 
rhytisma 
— 
9 
- 
— 
— 
— 
— 
0 
ginsburgi 
— 
56 
1 
1 
— 
— 
— 
2 
billykrietei 
— 
89 
3 
— 
— 
— 
— 
0 
stigmosus 
— 
12 
— 
— 
— 
— 
— 
0 
pusillus 
— 
22 
1 
— 
— 
— 
— 
2 
pelicanus 
— 
56 
1 
— 
— 
— 
— 
3 
marginatus 
2 
77 
11 
— 
— 
— 
— 
9 
piger 
2 
137 
1 
— 
— 
— 
— 
1 
trewavasae 
— 
4 
49 
11 
3 
— 
— 
6 
kyaropterygium 
— 
— 
1 
13 
— 
— 
— 
0 
minor 
— 
2 
— 
74 
1 
— 
— 
1 
parvus 
— 
1 
— 
33 
6 
35 
— 
5 
ommaspilus 
— 
— 
— 
28 
— 
— 
— 
0 
diomedeanus 
— 
— 
9 
13 
160 
6 
13 
17 
jenynsi 
— 
— 
4 
2 
62 
2 
6 
10 
plagiusa 
— 
— 
22 
24 
85 
4 
1 
5 
urospilus 
— 
— 
4 
8 
74 
15 
4 
5 
plagusia 
— 
— 
5 
2 
33 
— 
1 
3 
civitatium 
— 
— 
8 
19 
128 
7 
3 
6 
tessellatus 
— 
— 
10 
11 
209 
3 
15 
30 
oculellus 
— 
— 
2 
2 
55 
— 
3 
2 
caribbeanus 
— 
— 
8 
— 
69 
2 
— 
5 
first three, or in unusual cases, the first five inter- 
neural spaces. Only data for occurrence of predomi- 
nant patterns are reported here (additional informa- 
tion on variation in this character was presented in 
Munroe, 1992). The number of dorsal pterygiophores 
inserted into interneural spaces 1-3 was found to be 
diagnostic for species or groups of species of 
Symphurus (Munroe, 1987; 1992). Interdigitation 
patterns are recorded as a formula, such as 1-3-2 (Fig. 
IB), indicating that one pterygiophore inserts into 
interneural space one, three into interneural space 
two, and two into interneural space three. The first 
neural spine abuts directly against the cranium so 
that there is no obvious space between it and the 
cranium. Therefore, the first interneural space re- 
flected in the formula is that between the first and 
second neural spines. 
Caudal-fin rays (Table 3) Previous authors (Gins- 
burg, 1951; Mahadeva, 1956; Menezes and Benvegnu, 
1976; Munroe, 1987, 1990, 1991) have found that the 
caudal-fin ray count is extremely conservative within 
species of this genus. Previous studies have included 
the ultimate dorsal- and anal-fin rays, which lie on 
the same vertical plane as the caudal-fin rays (Fig. 
4, B-C), in the caudal-fin ray counts. This method is 
followed in the present study. Counts are usually even 
numbers (10, 12, 14) and rarely odd numbers (11 in 
5. urospilus). 
Dorsal (Table 4J and anal-fin rays (Table 5J These 
include all rays except the ultimate ray. The thick, 
muscular gonadal duct preceding the first anal-fin 
ray is not counted. 
Vertebral counts (Table 6| All western Atlantic 
Symphurus consistently have nine abdominal verte- 
brae, three without and six with haemopophyses; 
abdominal vertebral counts are thus reported as 
(3+6). Counts of total vertebrae include the urostylar 
centrum. 
Hypural counts (Fig. 4, B-CJ These include all 
separate hypurals without any implied interpreta- 
tion of the fate (fused or lost during ontogeny) of the 
fifth hypural, which may not always be present as a 
separate element. 
Scale counts (Fig. 2D) Accurate, repeatable scale 
counts are difficult to make on species of Symphurus, 
