Fig. 1

External anatomy and body plan organization of Echinoderes (Kinorhyncha). All views with anterior to the top. a Confocal z-stack projection of the autofluorescent cuticle of Echinoderes spinifurca, lateral view with ventral to the left, head extended. b Differential interference contrast (DIC) micrograph of E. spinifurca, lateral view with ventral to the left, head extended. c-e Scanning electron micrographs (SEM) of E. spinifurca in right dorsolateral view, head extended (c), Echinoderes ohtsukai in ventral view, head retracted (d), and Echinoderes horni in ventral view, head partially retracted (e). Scale bars: 50 μm in all panels. Abbreviations: h, head; i, introvert; lts, lateral terminal spine; lvs, lateroventral spine; mc, mouth cone; mds, middorsal spine; n, neck; s1, segment 1; s11, segment 11; te, tergal extension; tu, tube