I 
462 Fishery Bulletin 1 13(4) 
A few, small isolated spots on the 
anterolateral side of the trunk were 
present in larvae ranging between ~5 
and 7.5 mm (Fig. 3, C-E). Pigmenta- 
tion along the midventral line con- 
sisted of a short series of 3-4 small 
spots (Fig. 3, B-F). As the caudal 
rays developed, less prominent spots 
appeared in the middle of the hy- 
pural margin (Fig. 3, E and F). 
Abundance and distribution of larvae 
Larvae of A. patachonicus were col- 
lected from mid-November to mid- 
March (during the years described 
previously in this section), between 
40°31'S and 42°28'S, somewhere 
above the bottom in water up to 52 
m deep (Table 1; Fig. 1). At stations 
where larvae were captured, mean 
water temperature ranged broadly 
between 10.5°C and 17.9°C. Over- 
all, both the frequency of occurrence 
and larval density were low at sta- 
tions where larvae were caught: be- 
tween 1 (2.16 larvae/1000 m 3 ) and 
111 larvae (750.62 larvae/1000 m 3 ) 
were collected in shallow tows to the 
east of the mouth of the SMG and 
within the SJG, predominantly in the 
eastern domain (sensu Amoroso and 
Gagliardini, 2010) (Table 1). The dis- 
tribution pattern of small preflexion 
larvae matched the overall distribu- 
tion of larvae of A. patachonicus in 
the study area. 
Discussion 
In this study, the eggs and yolk-sac 
larvae came from a fertilization ex- 
periment, and that origin confirmed 
their species identity. Morphologi- 
cal features, including the develop- 
ment of the opercular complex and head spination, the 
sequence of development of meristic characters, and 
the position and relative size of the melanophores 
in preflexion, flexion, and postflexion larvae, allowed 
reconstruction of a developmental series and iden- 
tification of the remaining individuals studied as A. 
patachonicus. 
At present, the larval development has been de- 
scribed for only 2 of the 11 species of Acanthisti- 
us. Baldwin and Neira (1998) studied the larvae of 
the western wirrah (A. serratus ) from Western Austra- 
lia, and Brownell (1979) described the eggs and lar- 
vae of the koester (A. sebastoides ) from the southern 
coast of Africa. For our study, we considered that the 
M 
larvae (Fig. 3, E and F), a group of stellate external 
melanophores was located in the parietal region, and 
another internal group was located beneath the lon- 
gest preopercular spine. The parietal patch of melano- 
phores increased in size in the posttransition juvenile 
(Fig. 3F). A large internal melanophore was present at 
the base of the cleithrum in advanced preflexion lar- 
vae (Fig. 3, C-F). 
Considerable internal pigmentation developed in the 
dorsal area of the gut cavity and gas bladder, primarily 
on the surface of the viscera. The number of melano- 
phores over the gut increased with development. A few 
internal melanophores also were present at the ventral 
margin of the gut (Fig. 3, B-F). 
0.40 
0.35 
0.30 
0.25 
0.20 
040 
0.35 
0.30 
0 25 
0.20 
0 15 
0.75 
0.65 
0.55 
0.45 
0.35 
0 
i CD i 
0 ^ 
— I i 
2 3 4 5 6 7 
B 
—i r— 
8 9 
K+H 
O-' © 
1 1 1 1 r — - — ~i — r* 
23456789 
i ( 'T> i 
ttJ7l 
© d) 
^0 0 
2 3 4 
— i 1 1 i r— 
5 6 7 8 9 
Body length (mm) 
13 14 
13 14 
Adult 
Adult 
1 1 
13 14 
Adult 
Figure 4 
Body proportions of Acanthistius patachonicus (trunk region) examined 
for this study and collected on the Argentine shelf, 2008-2013: (A) head 
length, (B) body depth, and (C) preanal length. Bubble size in each plot 
is proportional to the number of larvae in each size range (from 1 to 14 
larvae). Solid bars on bubbles indicate standard deviations for mean body 
lengths (BLs) and for the proportions of BL. Adult proportions were taken 
from Nakamura et al. (1986). Vertical dotted lines indicate discontinuities 
along the x-axis. 
