Fig. 4

Fenestrulina joannae. A Overview of a zooid. B Overview from the frontal side, showing alpha-tubulin-lir in orange and f-actin in gray. Volume rendering. C Overview from the frontal side, showing alpha-tubulin-lir structures in orange. Volume rendering. D Detail of the lophophoral base. Alpha-tubulin-lir in orange. Volume rendering. E Detail of apertural area. Alpha-tubulin-lir in gray. Maximum intensity projection. Abbreviations: afn – abfrontal tentacle neurite bundle, cg – cerebral ganglion, CON – circumoral nerve ring, ctsn – compound tentacle sheath nerve, d – distal, dtsn – direct tentacle sheath nerve, int – intestine, lb. – lophophoral base, lvn – laterovisceral neurite bundle, mvn – mediovisceral neurite bundle, opn – opercular nerve, opo – operculum occlusor, p – proximal, pbs – parietal branching site, pdi – parietodiaphragmatic muscle, pdin – parietodiaphragmatic nerve, phm – pharyngeal musculature, php – pharyngeal nerve plexus, pm – parietal muscle, pmn – parietal muscle nerve, rm. – retractor muscle, sph – sphincter muscle, spn – sphincter nerve, tc – tentacle cilia, tfd – trifid neurite bundle, tm – tentacle muscle