Light photomicrographs of Demidospermus paranaensis. A – whole worm in ventral view (CHIOC37255b) showing the tegument annulations (TA). B – MCO: accessory piece (AP); base of the MCO (BMCO); prostatic reservoir (PR) (CHIOC37255b). C – sclerotized distal portion of the deferens duct, observed at varying depths, from left to right, ventral to dorsal: asterisk indicates the same topographical region in D. D – vagina (VG) and vaginal canal (VGC) (CHIOC37255d). E – ventral bar (VB) (CHIOC37255b). F – dorsal bar (DB) (CHIOC37255b). Scale bar = 100 µm (A), 25 µm (B, D–F), 10 µm (C).