Fig. 1

Scanning electron micrographs showing mouth cone and introvert details in Semnoderes armiger. a Outer oral styles. b Introvert sections 1 and 2. c Introvert section 9. d Introvert section 4. e Lateral view of partly retracted introvert showing sections 2–5. f Ventral view of partly retracted introvert showing sections 10, 1 and 2. mvp midventral placid, pl placid, sc scalid, sp spinoscalid, tr trichoscalid. Digits after labels refer to mouth cone and introvert ring numbers