title: Ultrastructural study of sperm cells in Acanthocolpidae: the case of Stephanostomum murielae and Stephanostomoides tenuis (Digenea).
abstract: The mature spermatozoa of Stephanostomum murielae and Stephanostomoides tenuis are described by transmission electron microscopy. They present several ultrastructural features previously reported in other digeneans. Their spermatozoa possess two axonemes of different length showing the 9 + '1' trepaxonematan pattern, four attachment zones, two mitochondria (with an anterior moniliform one in S. murielae), a nucleus, two bundles of parallel cortical microtubules, external ornamentation of the plasma membrane, spine-like bodies and granules of glycogen. The main differences between the mature spermatozoon of S. murielae and S. tenuis are the maximum number of cortical microtubules, the morphology of the anterior spermatozoon extremity and the anterior mitochondrion. This study is the first concerning members of the family Acanthocolpidae. The main ultrastructural characteristics discussed are the morphology of the anterior and posterior spermatozoon extremities, antero-lateral electron dense material, external ornamentations, spine-like bodies and number and morphology of mitochondria. In addition, the phylogenetic significance of all these ultrastructural features is discussed and compared to molecular results in order to highlight the complex relationships in the Digenea.
authors.affiliation: SERME Service d'Étude et de Recherche en Microscopie Electronique, UMR 6134-SPE CNRS-Università di Corsica , Corte, Corsica , France ; Laboratory of Evolutionary Biology, Ecology and Management of Ecosystems, Cheikh Anta Diop University of Dakar , Dakar , Senegal.
authors.forename: Abdoulaye J S
authors.initials: AJ
authors.lastname: Bakhoum
authors.affiliation: SERME Service d'Étude et de Recherche en Microscopie Electronique, UMR 6134-SPE CNRS-Università di Corsica , Corte, Corsica , France.
authors.forename: Yann
authors.initials: Y
authors.lastname: Quilichini
authors.affiliation: ISYEB, Institut de Systématique, Évolution, Biodiversité (UMR7205 CNRS, EPHE, MNHN, UPMC), Muséum National d'Histoire Naturelle , Paris Cedex , France.
authors.forename: Jean-Lou
authors.initials: JL
authors.lastname: Justine
authors.affiliation: Department of Life Sciences, Natural History Museum , London , United Kingdom.
authors.forename: Rodney A
authors.initials: RA
authors.lastname: Bray
authors.affiliation: Laboratory of Evolutionary Biology, Ecology and Management of Ecosystems, Cheikh Anta Diop University of Dakar , Dakar , Senegal.
authors.forename: Cheikh T
authors.initials: CT
authors.lastname: Bâ
authors.affiliation: SERME Service d'Étude et de Recherche en Microscopie Electronique, UMR 6134-SPE CNRS-Università di Corsica , Corte, Corsica , France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Marchand
keywords: Phylogeny; Platyhelminthes; Sperm cells; Transmission electron microscopy; Trematoda