The study of the early life of ommastrephid squids is a difficult task. Main reasons are: 1) the scarcity of species-specific taxonomic characters necessary to identify wild rhynchoteuthion paralarvae and, 2) the difficulties to obtain egg masses under laboratory conditions. Aiming to determine factors influencing early development and to analyze the external morphology of the hatchlings, we used in vitro fertilization techniques to obtain embryos and hatchlings of the main ommastrephid species from the Mediterranean Sea: Illex coindetii, Todaropsis eblanae and Todarodes sagittatus. A close relationship was observed between the incubation temperature, egg size and duration of embryonic development. The general chromatophore pattern of the hatchlings was described, though some individual variation was noticed. The skin sculpture of the external mantle surface resulted to be a potential taxonomic character in fresh hatchling individuals. Binocular microscope observations showed a network of cells, mostly hexagonal in shape, in the skin of Todaropsis eblanae, absent in Illex coindetii. Scanning electron microscope analysis revealed the presence of epidermal lines and hair cells over the mantle, head, arms and funnel, as well as dense cilia over the olfactory organ. Conspicuous buccal filaments were observed in the mouth area, maybe related to the first feeding mode of rhynchoteuthions. Observations of wild ommastrephid paralarvae collected from oceanographic cruises from NW Mediterranean Sea were also reported. In vitro fertilization techniques used in the laboratory proved to be a useful tool in the study of the early life of oceanic squids

Cephalopod International Advisory Council (CIAC) Symposium 2012: "Interdisciplinary approaches to cephalopod biology", 27 October - 02 November 2012, Florianópolis, Santa Catarina, Brazil

Peer Reviewed