Figure 5 | Scientific Reports

Figure 5

From: Brain regionalization genes are co-opted into shell field patterning in Mollusca

Figure 5

Summary of Gbx-expression (red) during polyplacophoran, solenogaster, and bivalve development. Anterior (a)-posterior (p) axes indicate the orientation. Asterisks mark the mouth opening. (a) Early trochophore larva (12 hpf) of the polyplacophoran Acanthochitona crinita possess an episphere (ep) that is divided from the hyposphere (hp) by a prototroch (pt). The anteriormost region of the episphere exhibits an apical organ with a (ciliary) apical tuft (at). (b) Metamorphic competent individual (65 hpf) of A. crinita showing seven shell fields with each one row of Gbx-expressing cells on the dorsal side and a foot (f) on the ventral side. (c) Early test-cell larva (0–1 dph) of the solenogaster Wirenia argentea exhibit large and flattened test-cells (tc). (d) In mid-stage test-cell larva (10–11 dph) of the solenogaster W. argentea Gbx is expressed in the anlagen of the cerebral ganglia (cg), in cells (2) that line the peri-imaginal space (pis) and in cells that are associated with the pedal nerve cords (pc). (e) Late test-cell larva (12 dpf) of the bivalve Nucula tumidula possess large and flattened test-cells, a mouth, and anus (an). The shell fields (sf) give rise to both shell valves (s). (f) Postmetamorphic individuals (22 dpf) of N. tumidula shed all test-cells which are subsequently ingested. Abbreviations: mc, mantle cavity; stm, stomach. Scale bars: 50 µm.