Villanueva Gomila et al.: Early life history of Acanthistius patachomcus 
461 
2.1 mm 
B 
3.9 mm 
5.2 mm 
E 
13.1 mm 
Figure 3 
Illustrations of early stages of Acanthistius patachonicus: (A) 
yolk-sac larva (2.1 mm body length [BLJ); preflexion at (B) 3.9 
mm BL, (C) 5.2 mm BL, and (D) 5.8 mm BL; (E) flexion (7.5 mm 
BL); (F) postflexion (8.4 mm BL); and (G) posttransition juvenile 
(13.1 mm BL). 
In early preflexion larvae, the preopercle 
was a partially ossified triangular plate with 
a sharp point where a spine would develop lat- 
er. Its anterior margin was slightly thickened 
(Fig. 7A). In advanced preflexion larvae, the 
larger preopercle ossified completely, and its 
anterior margin became thicker. Two minute 
foramina and a well-defined posteroventral-ori- 
ented spine developed on the posterior margin 
of the preopercle (Fig. 7B). The opercle ossified 
partially and had a thickened margin. 
In early flexion larvae, 2 anterior and 3 pos- 
terior preopercular spines were present (Fig. 
70. The middle spine was the largest, followed 
in size by the dorsal spine. The ventral spine 
was minute. The triangular-shaped opercle os- 
sified completely and articulated with the hyo- 
mandibular at this stage. The subopercle was 
incipient and located below the opercle; the in- 
teropercle was situated below the middle pre- 
opercular spine. 
In advanced flexion, the preopercle main- 
tained its overall shape and increased in size 
(Fig. 7D). The opercle developed an anterior 
projection and a posterior spine. The U-shaped 
subopercle ossified, occupying the whole space 
between the opercle and the interopercle. The 
supracleithrum, bearing 1 spine, was already 
evident at this stage. By late flexion, all ele- 
ments were completely ossified (Fig. 7E). The 
anterior preopercular margin had 3 spines; 
the middle one was the largest. The long, mid- 
posterior preopercular spine extended beyond 
the cleithrum. The interopercle reached the 
ventral posterior preopercular spine. 
In postflexion (Fig. 7F, the posttransition ju- 
venile), the preopercle formed an approximate 
right angle with 3 small, anterior spines and 6 
posterior spines; the 4 lower posterior spines 
were larger (the spine at the angle was larg- 
est) and 3 of these spines were ventrally ori- 
ented. The supracleithrum had 3 spines, and 
the interopercle had 2 spines. The opercle had 
3 spines — the one in the middle forming a mid- 
dle opercular ridge. The V-shaped subopercle 
had 4 acute vertices. 
In larvae >7.5 mm, there was a supraocular 
crest and 2 posttemporal spines (Fig. 3, E-G). 
Pigmentation pattern Pigmentation pattern in 
formalin-preserved larvae of A. patachonicus 
consisted of a few melanophores in specific 
positions. Yolk-sac larvae were unpigmented 
(Fig. 3A). In 3.9-mm preflexion larvae, pig- 
mentation on the head consisted of one ex- 
ternal spot at the angle of the lower jaw and 
another posterior and dorsal to the eye (Fig. 
3B). A small internal spot also appeared at 
the base of the pectoral buds anterior to the 
cleithrum (Fig. 3C). In flexion and postflexion 
