Embryonic and early postembryonic development of the burrowing crayfish, Virilastacus araucanius (Faxon, 1914) (Decapoda, Parastacidae) under laboratory conditions

摘要

The stages and duration of the embryonic and early postembryonic development of the burrowing crayfish, Virilastacus araucanius are described, in water at temperatures between 10.0 and 21.0degreesC, with 8.5 to 9.0 mg/l of dissolved oxygen, pH 6.8 to 8.5, and hardness of 49.8 ppm CaCO3. The morphological changes observed on the egg surface allow to distinguish 5 embryonic stages. After hatching, two moults separate three juvenile stages. The first two juvenile stages lack uropods and remain attached to the female. In stage 3, the juvenile is similar to the adult, both in morphology and behaviour, and becomes independent from the mother. Embryonic development lasts 120 days, and the postembryonic stages take another 20 days until the emergence of juvenile stage 3. The development is direct, with incubation of large eggs, rich in yolk, and parental care over juvenile stages I and 2.