Fig. 5

SEM micrographs of the surface topography of Phyllodistomum pseudofolium. a Body of a mature worm, ventral view. b Oral sucker rim; note two papillae situated on each side of the frontal tubercle, six papillae arranged in an inner ring, two lateral pairs of papillae, and four papillae situated within the sucker cavity (inset, papilla and secretory pore close to the oral sucker). c Forebody, ventral view showing five pairs of papillae arranged symmetrically in two ventro-lateral rows. d Four symmetrically arranged papillae on the internal surface of the oral sucker. e Partly retracted ventral sucker showing four symmetrically arranged papillae within the sucker cavity; note rather negligible ‘acetabular fold’. f Part of the ventral surface of the forebody showing the presence on each side of both ventro-lateral and lateral rows of papillae. g Retracted ventral sucker showing the lack of papillae on the sucker rim and pronounced ‘acetabular fold’. h Posterior notch, dorsal view; note the irregular surface and lateral papillae. Abbreviations: af, acetabular fold; ft, frontal tubercle; gp, genital pore; hb, hindbody; ifr, inner papilla on the ventral surface of the forebody; ip, papilla of the inner ring of the oral sucker; lfr, papilla of the lateral row on the ventro-lateral margin of the forebody; lp, lateral papilla beside the frontal pit; op, papilla of the outer ring of oral sucker; os, oral sucker; p, papilla; pn, posterior notch; sa, sucker aperture; sp, secretory pore; tr, transverse tegumental ridges; vs, ventral sucker; vsr, ventral sucker rim