Beschreibung:
<jats:p>In this study, fecundity of <jats:italic>Munida gregaria</jats:italic> in northern Patagonia was analysed in relation to size and compared with other studies in different sites along its latitudinal distribution. Also, morphological changes in embryos reared in the laboratory, and the chronology of its appearance were observed. Fecundity (total number of eggs in a clutch) was strongly correlated to size (carapace length in mm) (R = 0.638) and the regression equation fitted by least squares was Log<jats:italic>(</jats:italic>F<jats:italic>)</jats:italic> = −<jats:italic>1.37</jats:italic> + <jats:italic>3.85</jats:italic> · <jats:italic>log(</jats:italic>CL<jats:italic>)</jats:italic>. Size specific fecundity was higher than in southern locations along Patagonia. Recently extruded eggs are smaller than in southern Patagonia measuring an average of 530 μm in diameter and 0.043 mm<jats:sup>3</jats:sup> in volume. When ready to hatch, those measures increased by 30% and 50% respectively. Complete embryonic development lasted an average of 27.9 days at fixed temperature of 11°C. Five development stages were defined based on morphological changes: (1) from fertilization to the appearance of embryonic primordium (2–3.5 days); (2) embryonic tissues occupying less than half of the egg perimeter in lateral view (7–10 days); (3) embryonic tissues without pigments and occupying more than half of the egg perimeter in lateral view (5–8 days); (4) embryos with reddish eye pigments and chromatophores (4–6 days); and (5) ocular globe completely pigmented (3–4 days).</jats:p>