Fig. 8

Expression of Ntu-Pax2/5/8 during postlarval development of the bivalve Nucula tumidula. Dorsal (d)–ventral (v), anterior (ant)-posterior (p), and left (l)-right (r) axes indicate the orientation. a Ntu-Pax2/5/8 expression in the mantle of a 22 dpf old larva during onset of metamorphosis. Ntu-Pax2/5/8 expression is restricted to the mantle (m) margin and a bilateral expression domain located in the postero-ventral central region but not the foot (f). Faint expression (arrowhead) is still visible on the dorsal side of the animal close to the hinge (h). Note the test cells (tc) being ingested by this specimen. b Confocal reflection (Ntu-Pax2/5/8 expression in red) and autofluorescence (grey) scan of a single optical section of the specimen shown in (a) (same orientation). All test cells and the apical organ (not shown) are shed and engulfed during metamorphosis. c Ntu-Pax2/5/8 expression in a settled 22 dpf old individual that has engulfed all test cells. Note the Ntu-Pax2/5/8 expression along the mantle margin (arrowheads). Inset: Ventral view of a similar staged settled animal. d Confocal reflection (Ntu-Pax2/5/8 expression in red) and autofluorescence (grey) scan of a single optical section of the same 22 dpf old specimen as shown in (c) (same orientation). A different confocal plane of the boxed area is shown in the inset highlighting test cells in the stomach (stm) of the settled larva. e Ntu-Pax2/5/8 expression along the ventral mantle margin in a further developed specimen (22 dpf) with no test cells visible in the stomach (not shown). Note the lack of Ntu-Pax2/5/8 expression along the dorsal mantle area close to the hinge. f Posterior view of the same specimen as shown in E. Scale bars: 50 μm