Early life history of three Patagonian zoarcids

摘要

Zoarcids are well represented in the intertidal zone of the Patagonian coast. They are typically oviparous with parental care, but so far there is little information on their ontogenetic development. The aim of this study was to describe the early developmental stages of 3 zoarcid species: Iluocoetes elongatus, Phucocoetes latitans and Dadyanos insignis. Egg masses were sampled from these 3 species in the intertidal zone of the R a Deseado estuary (Santa Cruz, Argentina), and placed in suitable aquaria to obtain postlarvae and subsequent stages. Results showed that I. elongatus has the largest eggs of the 3 species with 4.94 mm in diameter, 4.93 mm in D. insignis and 4.20 mm in P. latitans. The postlarvae hatch with a high degree of development (with hatching size of 17.5 mm of standard length (SL) of I. elongatus, 18 mm SL of P. latitans and 22 mm SL of D. insignis), differing from juveniles by the presence of a large yolk sac. The pigmentation pattern fully corresponds to that of adults and during development it becomes increasingly intense. The cephalic portion of the lateral line is also totally developed at hatching time.