Fig. 4

Confocal maximum projections of an inverted pharynx of G. tridactyla analyzed as total. Fluorescence in situ hybridization (FISH) coupled with antibody staining against GLTx, and TO-PRO®-3 Iodide counterstaining. a Overview of an inverted glycerid pharynx comprising four cross arranged putative venom glands each connected to a tooth, and four corresponding pharyngeal lobes (three of them marked by an arrow). b Fluorescence in situ hybridization (FISH) revealed a clear GLTx signal in the lobes (marked by arrows) and tissue at the base of the teeth. Note that there is no distinct staining visible in the putative venom glands. c Distinct GLTx-IR staining (marked by arrows) is solely restricted to the pharyngeal lobes. Note that there is no staining signal inside the putative venom glands or additional pharynx tissues. vg, putative venom gland. Scale bars: 100 μm (a–c)