Tissue and Cell 44 (2012) 15–21 Contents lists available at SciVerse ScienceDirect Tissue and Cell jou rn al h om epage: www.elsevier.com/locate/tice Sperm ultrastructure of the digenean Aphallus tubarium (Rudolphi, 1819) Poche, 1926 (Platyhelminthes, Cryptogonimidae) intestinal parasite of Dentex dentex (Pisces, Teleostei) J. Foata, Y. Quilichini ∗ , S. Greani, B. Marchand CNRS UMR 6134, University of Corsica, “Parasites and Mediterranean Ecosystems” Laboratory, BP 52, 20250 Corte, France a r t i c l e i n f o Article history: Received 26 September 2011 Received in revised form 7 October 2011 Accepted 10 October 2011 Available online 14 November 2011 Keywords: Ultrastructure Spermatozoon Dentex dentex Digenea Cryptogonimidae TEM a b s t r a c t The ultrastructural organization of the spermatozoon of a cryptogonimid digenean, Aphallus tubarium, a parasite of Dentex dentex, is described. The spermatozoon possesses the elements found in other dige- neans: two axonemes with 9 + “1” pattern, a mitochondrion, a nucleus, cortical microtubules, external ornamentation and spine-like bodies. However, the mitochondrion appears as a cord with a bulge; this characteristic has never been described in other studied cryptogonimid and in other digeneans except in one lepocreadiid, Holorchis micracanthum. Likewise, the presence of a thin cytoplasm termination in the anterior part of the spermatozoon has never been pointed out in the cryptogonimids. © 2011 Elsevier Ltd. All rights reserved. 1. Introduction Digenan trematodes have been the subject of many ultra- structural surveys of spermatozoa (e.g., Gracenea et al., 1997; Baptista-Farias et al., 2001; Kacem et al., 2010). These results have been used in different phylogenetic studies (e.g., Ehlers, 1986; Brooks et al., 1989; Justine, 1997, 2001; Rohde et al., 1993). The present work concerns the ultrastructural survey of the spermatozoon in a digenean species, Aphallus turbarium (Rudolphi, 1819) Poche, 1926 (Cryptogonimidae), a parasite collected in com- mon dentex Dentex dentex Linnaeus 1758, belonging to Sparidae family from Valinco gulf (Mediterranean sea). The knowledge on the parasite of D. dentex is interesting because this fish is: a highly valued table fish in the Mediterranean region and elsewhere in the tropics; one of the favorite fishes of Mediterrannean fishermen, for his combativeness and its succulent taste; and of great potential for mariculture. The superfamily Opisthorchioidea Loos, 1899 comprises three families: Cryptogonimidae, Heterophyidae and Opisthorchiidae (Bray et al., 2008). ∗ Corresponding author. Tel.: +33 495 450 006; fax: +33 495 450 045. E-mail address: quilichini@univ-corse.fr (Y. Quilichini). Hitherto only three species of the family Cryptogonimidae have been the subject of this kind of study: Stemmatostoma pearsoni [also designated as Neochasmus sp. (Jamieson and Daddow, 1982; Cribb, 1986)], Anisocoelium capitellatum (Ternengo et al., 2009) and Adlardia novaecaledoniae [also designated as Siphoderina elongata (Quilichini et al., 2009; Miller et al., 2009)]. This investigation aims to compare first, sperm ultrastructural features of Aphallus tubarium with the three others Cryptogonim- idae species, and then with others Platyhelminthes in order to try to highlight criteria that can contribute to improve the phylogeny of Platyhelminthes. 2. Materials and methods Adults specimens of A. tubarium (Rudolphi, 1819) Poche, 1926 were collected live from the common dentex D. dentex (Linné, 1758), caught in the Valinco gulf (Mediterranean sea). The worms were removed alive from the digestive tract of their hosts. The parasites were carefully dissected, the entire genital apparatus of males were removed and the testes and seminal vesicle isolated fixed in cold (4 ◦ C) 2.5% glutaraldehyde in 0.1 M sodium cacody- late buffer at pH 7.2, rinsed in 0.1 M sodium cacodylate buffer at pH 7.2, post-fixed in cold (4 ◦ C) 1% osmium tetroxide in the same buffer for 1 h, dehydrated in ethanol and propylene oxide, embed- ded in Spurr (1969) and polymerised at 60 ◦ C for 24 h. Ultrathin sections (60–90 nm) of testis and seminal vesicle were cut on an 0040-8166/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.tice.2011.10.001