Fig. 2

Development of FMRFamide-like (green) and acetylated tubulin-like (red) immunoreactivity in P. dumerilii. Mid-nectochaete (a-d), late nectochaete (e-g), three-segmented errant juvenile worm (h-i). a: 3,5 dpf, ventral view showing the brain (asterisk) and the paired ventral cord. Arrows indicate the pairs of neurons in the larval segments 1–3. b: dorsal neuropil with FMRFa-lir neurons anterior (arrows) and posterior (arrowheads) to it; dr – dorsal roots of circumoesophageal connectives. c: Ventral neuropil; dr – dorsal roots of circumoesophageal connectives, vr – ventral roots of circumoesophageal connectives. d: Posterior part of the ventral cord with two neurons (arrows) in the third chaetigerous segment near the roots of parapodial nerves (arrowheads). e: 7 dpf, ventral view showing FMRF-lir structures in the body. Pn1–3– parapodial nerves of corresponding chaetigerous segments. f: dorsal view on the anterior body part showing brain neuropil (asterisk), innervation of the pharynx (ph) and gut (g). g: ventral nerve cords with adjacent FMRF-lir neurons. h: 16 dpf, FMRF-lir innervation of the ventral body part showing the subesophageal ganglion (seg) and pharynx (ph). i: FMRF-lir innervation of the dorsal body part showing brain neuropil (asterisk) with adjacent neurons, pharynx innervation (ph), and dorsal plexus with peripheral neurons (arrows). Scale bars = 20 μm