Fig. 6

Cleared and stained acronurus stage of an unidentified species of the genus Acanthurus. USNM 240068, 15.2 mm SL, Bermuda. Note that the scalpel-like spine on the caudal peduncle is not yet developed; the distal regions of the third and seventh dorsal-fin spines are missing. See “Materials and methods” for abbreviations. Scale bar is 2 mm