Embryonic stages of the Patagonian squid Loligo gahi (Mollusca : Cephalopoda)

The embryonic development of Loligo gahi was observed from 4-day-old eggs t o natural hatching. Egg strands spawned in the Valparaiso Bay, Chile, were transported to an open system tank for incubation. Temperatures ranged from 12.9 degreesC to 13.5 degreesC, salinities from 34 parts per thousand to 3 5 parts per thousand, and the photoperiod was 12L:12D. The period from spaw ning to hatching ranged from 30-35 days. The diameter of individual eggs ra nged from 2.5-3.2 mm, and the dorsal mantle length of hatchlings varied fro m 2.6-3.1 mm. The pattern of chronological appearance of organs was quite s imilar to loliginid species previously examined (Loligo aff. gahi, Loligo b leekeri, Loligo pealei, Loligo vulgaris reynaudii, and Loligo forbesii). Ho wever, L. gahi had a different (faster) development time and a smaller embr yo and hatchling size than L. bleekeri (Japan) and L. forbesii (eastern Atl antic Ocean). Differences (heterochronies) among species are discussed. All ometric growth of embryonic development in L. gahi using seven morphometric parameters was undertaken.