Gill structures of Yuyuanozoon magnificissimi from Yunnan, China. (A) Holotype, complete specimen CFM00059. (B) Enlargement of left gill slit 2 in (A) (box), showing the actual slit (arrowhead) and posterior radiating structures. (C,D) Close-up images of areas indicated in (B) (box) and that posterior of gill slit 3 in (A), respectively, both showing probable interconnection of radiating structures; these structures appear to represent underlying narrow grooves which may have functioned as part of the vascular system (less likely external gill filaments, as interpreted in ). G1-5, gills 1 to 5. Scale bars: 1 cm in (A), (B); 1 mm in (C), (D).