Fig. 2

Ciliation pattern changes show choanocyte chamber formation timing during metamorphosis in A. queenslandica. Nuclei are stained with DAPI (blue), and cilia are immunofluorescently labeled with an anti-acetylated alpha tubulin antibody (green). a A confocal section of the external epithelium of a competent larva. Cilia occur predominantly on the apical surface of epithelial cells (arrowhead), while there is no evidence of ciliation in the inner cell mass. b 6 hour postresettlement (hpr). The epithelial integrity is lost [28]. Cilia are becoming resorbed into former epithelial cells [36], and thus, ciliation is no longer found on the external surface of the postlarva (white line). c 12 hpr. Overall ciliation is reduced. Cells containing the resorbed cilia are internalized (white line) and have not yet reached the edge of the body (white line). d 24 hpr. Cells containing resorbed cilia spread across the body (white line). e 48 hpr. Small choanocyte chambers are forming throughout the body (arrowheads, circled by white dotted line), with some cells containing resorbed cilia still visible. f 72 hpr. Larger choanocyte chambers are present (arrowheads, circled by white dotted line), with fewer cells containing resorbed cilia visible. Scale bars 25 μm