Ultrastructural characteristics of the mature spermatozoon of the digenean Sclerodistomum italicum (Stossich, 1893) (Hemiuroidea, Sclerodistomidae) intestinal parasite of Hypocanthus amia (Teleostei, Carangidae)

Highlights • This paper provide the first ultrastructural data of the spermatozoon of a species becoming to the genus Sclerodistomum,. • It’s described for first time in this work, the presence of two types of extramembranous ornamentations in the mature spermatozoon of a digenean,. • The presence of short cortical microtubules in the anterior part of the spermatozoon in addition to the presence of only one bundle of cortical microtubules in the median part of the spermatozoon,. • In accordance to the others mature spermatozoa described in Hemiuroidea, the spermatozoon of Sclerodistomum italicum lack spine-like body.