Figure 5
Investigated morphological features of different semaphoronts of N. heteropoda (Pleocyemata). External morphology and developing nervous system of N. heteropoda. (a) Semaphoront Nh EN, showing naupliar appendage buds, but no ganglion anlagen. (b) Semaphoront Nh I+ showing postnaupliar appendage anlagen Mx1–T1. (c) Same semaphoront, showing naupliar ganglia and longitudinal neurite bundles. (d) Higher magnification image of the specimen shown in (c). Anlagen of the protocerebrum, deutocerebrum, tritocerebrum, mandible ganglion and nauplius eye are visible. (e) Semaphoront Nh II showing postnaupliar appendage anlagen T3 and additional posterior segment anlagen. (f) Same semaphoront showing postnaupliar ganglion anlagen from the first maxillary to the second thoracic segment. (g) Semaphoront Nh III showing the full set of segment anlagen. Pereiopod anlagen are present. (h) Same semaphoront, higher magnification of posterior pleon and telson anlage. No ganglion anlagen are observed in the pleonal segments, but continuous longitudinal neurite bundles extend anteriorly from the posterior pioneer neurons. (i) Semaphoront Nh IV, posterior pleon and telson anlage. Ganglion anlagen with extending lateral nerves are observed in all pleomeres, as well as a seventh pleonal ganglion anlage. (a, c, d, f, h, i) Maximum intensity projections of (a, f) phalloidin-signal (green), and (c, d, h, i) acetylated alpha-tubulin signal (red). In (h) and (i), nuclei are shown in blue. Intersegmental furrows are demarcated by dotted lines. (b) Blend projection, (e) and (i) normal shading projection of nuclear signal (TOPRO-3) shown in cyan. Abbreviations: Ol optic lobes, A1–P6 appendage anlagen of respective segments, T telson anlage, pc protocerebrum, dc deutocerebrum, tc tritocerebrum, md-g–P6-g ganglion anlagen of respective segments, lonb longitudinal neurite bundles, NEA nauplius eye anlage, NEN nauplius eye nerve, lmp longitudinal muscle precursor, P proctodeum, CP caudal papilla. Scale bars 100 μm in (a–c, e, f, h, i); 25 μm in (d); 500 μm in (g).