The eggs and hatchlings of the octopus Robsonella fontaniana (Cephalopoda: Octopodidae)

CentroNacionalPatago ´nico–ConsejoNacionaldeInvestigacionesCientificasyTecnicas(CENPAT–CONICET),BoulevardBrown2915 (U9120ACD), Puerto Madryn, ArgentinaVery little is known about the life history of Robsonella fontaniana. In particular, there are no descriptions of the early lifestages that enable correct identification of samples taken from the wild. In this work, eggs and hatchlings are described fromeggclutchesobtainedinthefieldwithbroodingfemalesandincubateduntilhatching.Individualeggsexhibitedmarkeddiffer-encesinstagesofembryonicdevelopmentwithineggclutchesorevenwithinasingleeggstring.Foroneclutchcollectedatearlystages ofembryonic development,embryogenesistook 91days at11.58Candfor asecondclutch atintermediate developmen-talstagesittook68daysat118Cand39daysat148C.Forthelaterclutchthehatchingperiodlasts25daysat148C.Theeggsand paralarvae were small, with an egg length of 3.9–5.2 mm, a dorsal mantle length of 2–3 mm and a total paralarvaelength of 3.4–6.0 mm. Chromatophore shape and distribution presented a very distinctive pattern. Characteristics of theeggs, egg strings and paralarvae make it possible to distinguish the early stages of R. fontaniana from those of other octopodidspecies found off the Atlantic coast of Patagonia.Keywords: cephalopods, octopod eggs, paralarvae, Robsonella fontaniana, Patagonian Atlantic coast