Fig. 5

Cirrate embryos with associated chorions. a Specimen N: extracted embryo with 5 mm ML, dorsal (left) and ventral view (right). The yellow-colored internal yolk sac can partially be seen through the artificially semi-transparent mantle tissue. b Specimen N: longitudinally ruptured chorion. c Specimen N: volume rendering of a contrast-enhanced 3D µCT data set of the embryo, right lateral view. d Specimen N: semi-transparent volume rendering of a contrast-enhanced 3D µCT data set of the embryo showing the wide U-shaped shell with central depression as well as further internal structures. e Specimen O: extracted embryo with 10 mm ML, dorsal (left) and ventral view (right). The yellow-colored internal yolk sac can almost fully be seen through the artificially semi-transparent mantle tissue. f Specimen O: longitudinally ruptured chorion. g Specimen O: volume rendering of a contrast-enhanced 3D µCT data set of the embryo, right lateral view. h Specimen O: volume rendering of a contrast-enhanced 3D µCT data set of the embryo showing suckers and cirri, ventral view. ar = arm, as = aerolar spot, ch = chorion, ci = cirrus, ey = eye, fc = fin cartilage, fi = fin, fu = funnel, is = internal yolk sac, mo = mouth, ol = optic lobe, pw = primary web, sh = shell, su = sucker. Scale bars = 1 mm