Fig. 9 in Loss of complexity from larval towards adult nervous systems in Chaetopteridae (Chaetopteriformia, Annelida) unveils evolutionary patterns in Annelida

Fig. 9 The larval neurogenesis of Chaetopterus variopedatus revealed by anti-5HT a-e and anti-FMRFamide staining f, g. Confocal maximum projections. Stages are shown in hours (hpf) or days past fertilization (dpf). a: 48 hpf the posterior pioneer neuron (ppn) is well-developed and distinct neurite bundles interconnect the posterior and anterior part of the larval nervous system (white arrowheads). Prominent ganglion cells (green arrowhead & green dashed line) mark the position of the later apical organ. b: The posterior pioneer neuron (ppn) possesses a sensory cilium and marks the ontogenetic origin of the posterior nervous system. c: Later in development, the