Development of larvae and juveniles of the alfonsins, Beryx splendens and B. decadactylus (Berycidae, Beryciformes).

Abstract

The larval development of the alfonsins, Beryx spp., is described from specimens collected from the central North Pacific Ocean (29 degree N, 179 degree E) during July 1984, primarily in the upper 50 m. Yolk-sac larvae, 1.5-3.0 mm standard length (SL), have pigment at the forebrain and midbrain, the anterior end of the oil globule, over the intestine above the anus, and around the tip of the notochord. Characters useful for identifying Beryx larvae include very elongate, early forming pelvic rays and anterior dorsal spines; a slightly S-shaped intestine about half the standard length; and sparse pigment restricted to internal pigment at the gas bladder, over the posterior intestine, and a spot located asymmetrically on the forebrain. Juvenile B. spendens and B. decadactylus , from the North Atlantic, differ from each other in dorsal fin ray count.