Fig. 11

Expression of Lbx at consecutive developmental stages in embryos of the onychophoran E. rowelli. Anterior is left in A–B′, and up in C–K; developing legs are numbered. Asterisks point to the proctodeum. Insets in A′ and B′ show the respective embryo stained with DAPI. A Stage 0–I embryo in ventral view. Inset shows the jaw and slime papilla segments in ventrolateral view. A′ Same embryo as in A, superimposed light micrograph and DAPI image. Dashed lines indicate transverse furrows. B Stage I embryo in lateral view. B′ Same embryo as in B, superimposed light micrograph and DAPI image. Arrowheads point to transverse furrows. C Stage II embryo in lateral view. Note the weak signal in the developing antenna (arrowhead). D Head of stage II embryo in ventral view. Note the weak signal in the developing antenna (arrowhead). E Detail of stage II embryo in ventrolateral view. Arrows indicate transverse furrows. F Stage II embryo in lateral view, superimposed light micrograph and DAPI image. Dashed lines demarcate transverse furrows in the posterior segments. G Stage III embryo in ventral view. H Anterior segments of the same embryo as in G in ventral view. I Stage IV embryo in ventral view. J Head of a stage IV embryo in ventral view. Arrowheads point to the expression in the cephalic lobes. K Fifth and sixth developing legs of stage IV embryo in ventral view. Abbreviations: as, antennal segment; at, developing antenna; cl, cephalic lobe; de, dorsal extra-embryonic tissue; js, jaw segment; jw, developing jaw; sp, developing slime papilla; ss, slime papilla segment; st, stomodeum; ve, ventral extra-embryonic tissue. Scale bars: A–G, J: 200 µm; H, K: 100 µm; I: 500 µm