Fig. 1

Microscopic images of naupliar instars (male) of Sacculina carcini Thompson, 1836. Right lateral view (upper side) and ventral view (lower side): a N1 (prematurely released), three portions of the antennule (black arrow), red pigments in cephalic region (white arrow); b N2 (0 h) just released by the externa, with furca deployed, and frontal horns opened laterally; c N3 (20 h), with furcal rami diverged; d N4 (44 h); e young N5 (52 h) red pigments in cephalic region (white arrow); f late N5 (104 h), with two spots of red pigments beneath the posterior region of the head shield (white arrow). N1–N5: naupliar instars 1–5. Scale bar 100 μm. Images with stereomicroscope (Olympus SZX7 associated with DP 20 camera)