English: Volume renderings of µCT scans of the fin with scales removed. a,b, Dorsal (a) and ventral (b) views of the fin with endoskeleton in grey and dermal rays in orange. Dotted lines indicate the boundary between ulna and ulnare. The dashed line indicates position of cross-section in e, which is oriented orthogonal to the plane of the fin web. c, Endoskeleton viewed from the proximal side with humerus removed. d, Reconstruction of endoskeletal elements with estimated boundary between the radius and intermedium. Scale bar, 1 cm. e, Cross sections of the fin rays, showing asymmetry in the size of dorsal and ventral hemitrichia. f–k, Humerus in dorsal (f), pre-axial (anterior) (g), ventral (h), postaxial (posterior) (i), proximal (j) and distal (k) perspectives. Scale bar, 1 cm. Proximal is up in f–i. Dorsal is up in j and k. Abbreviations: ar, anterior radial; cap, caput humeri; h, humerus; ir, intermedium; r, radius; rf, radial facet; m3, third mesomere, u, ulna; ul, ulnare; uf, ulnar facet.