Sperm ultrastructure of the gall bladder fluke Anisocoelium capitellatum (Digenea: Cryptogonimidae), a parasite of Uranoscopus scaber (Pisces: Uranoscopidae)

Abstract

Ultrastructure of mature spermatozoon of Anisocoelium capitellatum is described with transmission electron microscopy. The description gave evidence of some characteristics of this digenean. The male gamete presents features allowing the distinction between A. capitellatum and other digenetic trematodes. It is characterized by original anterior and posterior extremities. The peripheral doublets appear prior to the central cores in the anterior extremity of axoneme. In the distal part of the spermatozoon, these ultrastructural features are also the first elements disappearing in the axoneme 1 and the last remaining in the axoneme 2. Another important peculiarity of the spermatozoon is the presence of three mitochondria.

Spermatological characters of the digenean Rubenstrema exasperatum (Rudolphi, 1819) (Plagiorchioidea, Omphalometridae)

“…This is the case of the opecoelids Poracanthium furcatum, N. testiobliquum, and N. wisniewskii (Levron et al 2004b;Quilichini et al 2007aQuilichini et al , 2007c, the dicrocoeliid D. hospes (Agostini et al 2005), the troglotrematid Troglotrema acutum (Miquel et al 2006), and the allocreadiid C. metoecus (Quilichini et al 2007b). Additionally, a spermatozoon presenting three mitochondria was recently described in A. capitellatum, Euryhelmis squamula, Basidiodiscus ectorchus, and Sandonia sudanensis (Ashour et al 2007;Bakhoum et al 2009;Ternengo et al 2009). The application of some techniques such as the labeling of the mitochondria would be useful to elucidate the real number of mitochondria.…”

“…An anterior extremity exhibiting both axonemes is rare in spermatozoa of digeneans. In fact, most species described to date present only one axoneme in their anterior tip as reported for example in Anisocoelium capitellatum or P. gymnesicus (Gracenea et al 1997;Ternengo et al 2009). It is also interesting to notice that, in numerous studies, crosssections with a single axoneme are always interpreted as a posterior tip of sperm (Castilho and Barandela 1990).…”

Ultrastructure of the male gamete of Brachylecithum eliomydis (Digenea, Dicrocoeliidae)—A parasite of Eliomys quercinus (Rodentia, Gliridae)

“…Therefore, these ultrastructural criteria possess great phylogenetic interest in understanding the complexes relationships within Digenea in general and Dicrocoeliidae in particular (Agostini et al, 2005;Bakhoum et al, 2013a;Miquel et al, 2013;Quilichini et al, 2010b;Ternengo et al, 2009;Zhukova et al, 2014). Five ultrastructural characteristics present in the spermatozoon of B. eliomydis, are discussed below.…”

Spermiogenesis and ultrastructure of the spermatozoon of Wardula capitellata (Digenea, Mesometridae), an intestinal parasite of the sparid teleost Sarpa salpa in Senegal

“…This is the case of the opecoelids P. furcatum, N. wisniewskii, N. testiobliquum (Levron et al 2004b;Quilichini et al 2007a, c), the dicrocoeliid D. hospes (Agostini et al 2005), the troglotrematid T. acutum (Miquel et al 2006), the apocreadiid N. chabaudi (Kacem et al 2010) or the omphalometrid R. exasperatum (Bakhoum et al 2011b). Additionally, a spermatozoon with three mitochondria has recently been described in B. ectorchus, S. sudanensis, A. capitellatum and E. squamula (Ashour et al 2007, Bakhoum et al 2009, Ternengo et al 2009). Thus, the variation in the number of mitochondria in the mature spermatozoon could contribute to the interpretation of relationships at family level.…”

“…Such an anterior tip exhibiting both axonemes is rare in digenean spermatozoa. In fact, most species described until now present only one axoneme as in P. gymnesicus, Anisocoelium capitellatum or D. subclavatus (Gracenea et al 1997, Ternengo et al 2009, Bakhoum et al 2011a.…”