Munroe: Systematics of western Atlantic Symphurus 
71 
Symphurus trewavasae Chabamaud, 1 948 
(Figs. 8E, 36-37; Tables 1-10, 22} 
Trewavas's tonguefish 
Symphurus plagiusa (not of Linnaeus, 1766). Regan, 
1914:23 (Cabo Frio, Brazil). Lazzaro, 1973:245 
(Puerto Quequen, Argentina; in key). Roux, 
1973:176 (southern Brazil). Menni et al., 1984:202 
(reidentifications; previous citations by Roux 
(1973) for Brazil, and Lazzaro (1973) for Argen- 
tina correspond to S. trewavasae). 
Symphurus trewavasae Chabanaud, 1948:508 (origi- 
nal description; Cabo Frio, Brazil). Ginsburg, 
1951:185 (brief comparison with S. plagiusa). 
Menezes and Benvegnu, 1976:144 (redescription, 
photograph; diagnosed from S. plagiusa ; ecologi- 
cal notes). Menni et al., 1984:202 (southern Brazil 
to Argentina). Munroe, 1992:369, 377 (ID pattern; 
geographic, bathymetric distributions). Andreata 
and Seret, 1995:590 (continental shelf, Brazil). 
Symphurus plagusia (not of Schneider, in Bloch and 
Schneider, 1801). Andreata and Seret, 1995:590 (in 
part; specimen from 23°07'S, 42°03'W is S. 
trewavasae). 
Diagnosis Symphurus trewavasae is readily distin- 
guished from all congeners by the combination of 
predominant 1-3-3 ID pattern; 10 caudal-fin rays; 4 
hypurals; 88-94 dorsal-fin rays; 73-79 anal-fin rays; 
47-51, usually 48-49, total vertebrae; 67-77 scales 
in longitudinal series; unpigmented peritoneum; 
absence of pupillary operculum; absence of scales on 
blind sides of dorsal- and anal-fin rays; teeth along 
entire margin of ocular-side dentary; anterior 
one-half or less of margin of ocular-side premaxilla 
with teeth; lack of fleshy ridge on ocular-side lower 
jaw and membrane ostia; ocular surface with bold 
pattern of crossbands without caudal blotch; lack of 
pepper-dot pigment on blind side of body; and dor- 
sal, anal, and caudal fins without spots or blotches. 
Description A medium-size tonguefish attaining 
maximum size of ca. 139 mm SL. ID pattern usually 
1-3-3 (49/73 specimens), less frequently 1-4-2 (11/73) 
or 1-3-2 (4/73) (Table 2). Caudal-fin rays 10 (Table 
3). Dorsal-fin rays 88-94 (Table 4). Anal-fin rays 73- 
79 (Table 5). Total vertebrae 47-51, usually 48-49 
(56/70) (Table 6). Hypurals 4 (70/70). Longitudinal 
scale rows 67-77, usually 71-77 (Table 7). Scale rows 
on head posterior to lower orbit 15-20, usually lb- 
17 (Table 8). Transverse scales 31-37, usually 32-35 
(Table 9). 
Proportions of morphometric features presented in 
Table 22. Body moderately deep; greatest depth from 
approximately region of tenth anal-fin ray to mid- 
point of body; body tapering fairly rapidly posterior 
to midpoint. Head moderately short and moderately 
wide, narrower than body depth. Head shorter than 
wide (HW:HL 1.04-1.49, x=1.2). Lower head lobe 
width less than postorbital length; narrower than 
