Fig. S7

 Sequence of Collective SEC Behaviors During Fin Regeneration, Related to Figure 6. (A, B)

Brightfield view of adult zebrafish caudal fin at 10 dpa. Scale bars, 0.5 mm. Red boxes in (A) indicate areas where

z-stacked confocal images (B) were captured. Scale bars, 100 μm. White-dashed lines indicate the amputation plane.

Images in (A) and (B) were captured from the same animal. Scale bars, 100 μm. (C) Wounds seal in the first hour

post amputation (hpa) by interactions between alternating SEC sheets with distinct cell displacement and shape

responses. Many SECs are extruded at the amputation plane during this process. At 24 hpa, spared SECs are

recruiting to the regenerating area over long distances. By 36 hpa, do novo SECs are well-integrated with preexisting

SECs, and new SEC creation becomes the predominant cellular supply of surface epithelium. At late stages

in ongoing regeneration (10 dpa), fins retain many hypertrophic SECs at the distal regenerating tips. This phenotype

becomes fully resolves after completion of appendage replacement (30 dpa), and SECs have a similar size

distribution across the entire appendage. Pre-existing cells are labeled in blue; de novo SECs are labeled in yellow