Figure 8

Stage 12, Lateral furrow. All scale bars 100 μm. Sytox staining, a-a''; SEMs, b, c. a: Lateral view. a': Frontal view. Lateral to the stomodeum (Sto) are invaginating folds of precursor neural tissue (LF, lateral furrow). The pedipalps (P), cheliceres (Ch), and stomodeum are more pronounced. a'': Posterior view. The walking legs (visible L4) are more elongated and their tips touch each other. The ventral sulcus (VS, white dotted line) extends posteriorly almost the eighth opisthosomal segment (O8). b: Ventro-lateral view. Anterior to the stomodeum (Sto), the small bi-lobed anlage of the labrum (Lb) is visible. Postero-laterally on each precheliceral lobe (PcL), a kidney shaped lateral furrow (LF) is evident. c: Opisthosomal region. Eight separate opisthosomal segments (O1-O8) are visible whilst an additional segment (indicated by a white dotted line) is still connected to the growth zone (GZ). Small depressions (black arrows) of the primordial respiratory system are evident at the posterior insertion of the limb bud at opisthosomal segment two (O2). The ventral sulcus (VS, black dotted line) extends posteriorly to the seventh opisthosomal segment (O7).