Fig. 5

Elongation, segmentation, and leg development stages in H. exemplaris. Panels to the left show DAPI stained embryos. Models are provided to the right of each data panel. The key for the color-coding in models is provided at the bottom of the figure. a Early elongation (stage 11). b Late elongation (stage 11). a, b Arrowhead points to internalized cells that connect to the external ectoderm. c, d Stage 12. e, f Stage 13. e–e’’ Views from more lateral to more medial. e, f Dashed lines in the model denote the position of ectodermal furrows. g, h Stage 14. Anterior is towards the top in all panels. All panels show a lateral view of embryos facing right except for d, f, and h, which show bilateral views. All panels show internal anatomy, except for e and g, which show external features. ant anterior; ep1–ep4 endomesodermal pouch 1–endomesodermal pouch 4; fg foregut; l1–l4 leg 1–leg 4; pos posterior, t1–t4 trunk segment 1–trunk segment 4