Figure 1

The external morphology of five species of Echinoderes (Kinorhyncha). (A-H) Scanning Electron Microscopy (SEM). (A) Echinoderes spinifurca, lateral view, with ventral to the left, anterior to the top. Introvert and mouth cone are everted. (B) Echinoderes horni, lateroventral view, anterior to the top. Introvert and mouth cone are everted. (C) Echinoderes hispanicus, lateroventral view, anterior to the right. Introvert is everted, and the mouth cone is retracted. (D) Echinoderes sp., lateral view, with anterior and posterior toward the top, dorsal to the bottom. Introvert and mouth cone are everted. (E) Echinoderes dujardinii, lateroventral view, anterior and posterior toward the top. Introvert is everted and part of mouth cone is visible. (F) Echinoderes spinifurca, apical view of the mouth cone. (G) Echinoderes spinifurca, lateral view of the introvert and mouth cone, anterior to the top. (H) Echinoderes dujardinii, apical view. Introvert and mouth cone are retracted, and placids of the neck are closed. Abbreviations: h, head; i, introvert; lts, lateral terminal spine; lvs, lateroventral spine; mc, mouth cone; mds, middorsal spine; mvp, midventral placid; n, neck; oos outer oral style; pl, placid; ps, penile spine; psp, primary spinoscalid; s, segment; sc, scalids; t, trunk; te, tergal extension. Digits refer to segment number. Scale bar, 30 μm.