Rastrognathia macrostoma, Kristensen & Norrevang, 1977

Rastrognathia macrostoma View in CoL

SLIR and TyrTLIR nervous structures as well as DAPIstained cell nuclei are visualized with CLSM The brain consists of the central neuropil ( np, Figs. 7f, 8d) surrounded by perikarya and sensory structures (Figs. 7d–f, 8b–d). The SLI reactivity was detected in six brain cells (2 × dp, 2 × mp, 2 × lp, Figs. 7d, 8b) and two ventral brain commissures ( vac and vpc, Figs. 7b, 8c) forming a ring-shaped structure. In addition, a distinct dorso-anterior TyrTLIR commissure was visualized ( dac, Figs. 7e, 8d).

Three pairs of longitudinal SLIR and TyrTLIR nerve cords extend from the brain to the posterior commissure: ventro-lateral, lateral, and dorso-lateral ( vlc, lc, dc, Figs. 7a–c, e, f; 8); the two former are interconnected by a fine neurite in the anterior part of the trunk. A pair of peripheral SLIR anterior perikarya ( ap, Figs. 7a, b; 8a, c) projects neurites into the ventro-lateral nerve cords anterior to the pharynx, and a single middorsal TyrTLIR perikaryon ( mdc, Figs, 7c, 8e) is located above the male genital opening. A few ciliary gut receptors occur along the midventral line ( cgr, Fig. 5c, f).

The stomatogastric nervous system consists of a buccal ganglion ( bg, Fig. 8d View Fig ) with about 20 perikarya and a pair of buccal nerves ( bn, Fig. 8d View Fig ) extending along the pharyngeal bulb, both being TyrTLIR.

The rostral TyrTLIR sensory structures include three apical ventral ciliary organs ( vco, Figs. 7e, f; 8d), four pairs of compound cirri ( cc, Fig. 7e, f, one pair shown in Fig. 8d View Fig ), and three pairs of spiral organs, the two anterior ones larger-sized and with thicker bundles of cilia than the posterior one ( aso and pso, Figs. 7e, 8d).