Fig. 21
From: Within-family plasticity of nervous system architecture in Syllidae (Annelida, Errantia)
Exogoninae. Parapodial innervation. Maximum intensity z-projection of ventral sections. a1: α-tubulin-lir (grey) of a parapodium of Prosphaerosyllis marmarae. Three neurite bundles leave the ventral nerve cord to innervate the parapodium. The main parapodial neurite bundle is connected to the third segmental ring neurite bundle (yellow arrowhead). a2: Serotonin-lir (orange) and cell nuclei (magenta) of a parapodium of Pr. marmarae. Serotonin-lir of the main parapodial neurite bundle is less conspicuous and not all of the fine neurite bundles are visible, such as the most posterior fine neurite bundle of the parapodial innervation. A cluster of somata is present inside the parapodia. b1: α-tubulin-lir (grey) of a parapodium of Sphaerosyllis taylori. Four neurite bundles form the parapodial innervation. The main parapodial neurite bundle is connected to the third segmental ring neurite bundle (yellow arrowhead). b2: Serotonin-lir (orange) and cell nuclei (magenta) of a parapodium of Sph. taylori. The staining of the parapodial neurite bundles is weaker than in α-tubulin-lir, the most posterior fine neurite bundle is not stained. The nephridium is accompanied by a serotonin-lir signal in sexually active individuals. The chaetae have a strong autofluorescence at 568 nm in this species. Scale bars = 50 μm. Abbreviations: ac – acicle; acn – neurite bundle accompanying acicle; ap – anterior neurite bundle entering the parapodium; ch – chaetae; dpc – neurite bundle forming distal dorsal parapodial connective; mp – main parapodial neurite bundle; mpc – median dorsal parapodial connective; mn – median ventral nerve; mvn – main ventral nerve; n - nephridium; pc – parapodial cluster of somata; pln – neurite bundles innervating parapodial lobe; rp1 – root 1 of main parapodial neurite bundle; rp2 – root 2 of main parapodial neurite bundle; spc – tubuli of spermatocytes; vgl – ganglion of ventral nerve cord. Segmental neurite bundles in yellow: I-IV – segmental neurite bundles forming ring commissures, II refers to all neurite bundles comprising the parapodial innervation