152 



ONTOGENY AND SYSTEMATICS OF FISHES-AHLSTROM SYMPOSIUM 



Fig. 79. Young of Relropinna retropmna. 35 mm (above); and Aplochilon sp., 24 mm (below). 



5-7 mm long with little yolk anteriorly below pectoral fins. They 

 are very elongate, the vent posterior at more than 75% body 

 length, the trunk encompassed by a low finfold from head around 

 tail to yolk sac. Small pedunculate pectoral fins occur. Pigmen- 

 tation is confined to the eyes and a narrow band in mid-ventral 

 between head and vent. Newly hatched larvae disperse to sea 

 and are not fiirther studied (see Blackburn, 1950). 



Aplochilon taeniatus is recorded spawning in ft-esh water dur- 

 ing winter, the small (1.5 mm), spherical eggs being demersal 

 and attached to firm benthic objects, fecundity 2,500-3,000 and 

 development about 20 days. The larvae are very elongate and 



slender with a yolk sac beneath the pectoral fins. The vent is at 

 about 75% of body length. A finfold encompasses the trunk and 

 tail. Campos (1969) shows a single large melanophore just in 

 front of the vent. His figure of a larva presumably 8 mm long 

 (he states 80 mm) shows a series of melanophores along the 

 abdomen and a few on the lower caudal peduncle. Recent col- 

 lections of larval Aplochiton from Fiordo Aisen in southern 

 Chile show that some movement to sea occurs. At a length of 

 24 mm the late larva has well differentiated rays in the dorsal, 

 caudal, anal and pectoral fins and distinct pelvic fin buds are 

 evident (Fig. 79). An adipose fin is also differentiated. Pigmen- 



Fig. 80. Young of Galaxias maculatus. 14.5 mm (above); and Prolotrocles maraena 35 mm (below). 



