Fig. 1

Anatomy and major epidermal cell types of the pilidium larva. A Diagram of a trunk-disk stage pilidium (~ 2 weeks old) illustrating major anatomical features. The right cephalic and trunk disks are omitted for clarity. The dash line represents the outline of the apical organ, gut, esophagus and underside of anterior and posterior lobes in sagittal mid-plane. Primary ciliary band is in blue, inner ciliary bands are in purple, ciliary ridges are brown, axils are yellow. B A 4-day-old pilidium of Maculaura alaskensis injected as a zygote with mRNA encoding GFP-UtrCH, which highlights actin-rich structures including cell boundaries. This is the stage at which the marked larvae were scored. To illustrate major epidermal cell types, one or more cells of each type are color-coded: tile cells (green), foam cells (lavender), axillary cells (yellow), multiciliated cells of the primary ciliary band (teal), and uniciliated collar cells (red). Scale bar 50 μm