Ultrastructure of the spermatozoon of Macvicaria obovata (Digenea: Opecoelidae), a parasite of Sparus aurata(Pisces: Teleostei) from the Gulf of Gabès, Mediterranean Sea

Abstract

The ultrastructural organization of the spermatozoon of the digenean Macvicaria obovata (Opecoelidae) is described by transmission electron microscopy. Alive digeneans were collected from the digestive tract of Sparus aurata (Teleostei, Sparidae), caught from the Gulf of Gabès in Chebba, Tunisia (Eastern Mediterranean Sea). The male gamete of M. obovata is a filiform cell, tapered at both extremities and exhibits typical characters such as two axonemes of different lengths showing the 9+'1' trepaxonematan pattern, a nucleus, mitochondria, two bundles of parallel cortical microtubules, external ornamentation of the plasma membrane, spine-like bodies and granules of glycogen. Cortical microtubules are absent in the anterior spermatozoon extremity and appear after the disappearance of the electron-dense material. The first mitochondrion is of moniliform type and it is associated with the external ornamentation of the plasma membrane and spine-like bodies. The second mitochondrion is more posteriorly located, reaching the nuclear region. The present study provides new data on the mature male gamete of M. obovata that may be useful for the understanding of digenean relationships and phylogenetic studies.

A Review of Sperm Ultrastructural Characters in the Opecoelidae (Digenea) and Their Phylogenetic Implications, with New Data on Peracreadium characis, a Parasite of Diplodus puntazzo in Tunisia

“…The remaining Opecoelidae species, except for Macvicaria obovata , exhibit a type 2 sperm cell, with the maximum number of cortical microtubules located in the middle part of the spermatozoon (see Table 1 ). In M. obovata, the maximum number of cortical microtubules is located in the nuclear region of the spermatozoon after the disappearance of the first axonemes [ 36 ].…”

“…Later, Curran et al [3] incorporated the first molecular data for representatives of the Allocreadiidae Looss, 1902 into broader analyses of the Xiphidiata Olson, Cribb, Tkach, Bray & Littlewood, 2003. They synonymized the Allocreadioidea with the Gorgoderoidea Looss, 1901 and proposed that the families previously included under (Stossich, 1887), Allopodocotyle tunisiensis Derbel & Neifar, 2009 and Podocotyloides magnatestis Aleshkina & Gaevskaya, 1985 [28][29][30]; two Helicometrinae, namely Helicometra epinepheli Yamaguti, 1934 and Helicometra fasciata (Rudolphi, 1819) [31,32]; three Opecoelinae, namely Labracetabulum gephyroberici Reimer, 1987, Opecoeloides furcatus (Bremser in Rudolphi, 1819) and Poracanthium furcatum Dollphus, 1948 [33][34][35]; two Opistholebetinae, namely Heterolebes maculosus Ozaki, 1935 and Macvicaria obovata (Molin, 1859) [23,36] and two Plagioporinae, namely Nicolla testiobliqua (Wisniewski, 1933) and Nicolla wisniewskii (Slusarski, 1958) [37,38].…”

Sperm characters of Timoniella imbutiforme (Digenea, Opisthorchioidea, Cryptogonimidae), a parasite of the European seabass Dicentrarchus labrax

“…A moniliform mitochondrion was described for the first time by Bâ et al (2011) in the spermatozoon of the lepocreadiid Holorchis micracanthum. Since then, this type of mitochondrion has been found in the spermatozoon of other species such as the acanthocolpid Stephanostomoides tenuis (Bakhoum et al, 2015), the lepocreadiid Opechona bacillaris (Ndiaye et al, 2015), the opecoelids Allopodocotyle pedicellata and Macvicaria obovata (Bakhoum et al, 2017b;Kacem et al, 2017), the plagiorchiid Enodoitrema reductum (Ndiaye et al, 2012), and the cryptogonimid Aphallus tubarium (Foata et al, 2012).…”

Spermatological characters in the Lepocreadioidea, with first data on Holorchis pycnoporus (Aephnidiogenidae), a parasite of the Striped seabream Lithognathus mormyrus (Sparidae) from the Gulf of Gabes (Tunisia)

“…Stephanostomoides tenuis (Manter, 1963) (see Bakhoum et al, 2015c), the cryptogonimids Aphallus tubarium (Rudolphi, 1819) and Timoniella imbutiformis (Molin, 1859) (see Foata et al, 2012;Kacem et al, 2017a), the opecoelids Allopodocotyle pedicellata (Stossich, 1887) and Macvicaria obovata (Molin, 1859) (see Bakhoum et al, 2017b;Kacem et al, 2017b), the plagiorchiid Enodiotrema reductum Looss, 1901(see Ndiaye et al, 2012, and the sclerodistomoidid S. pacificus (see Bâ et al, 2020b). In the Lepocreadioidea, this type of mitochondrion has been noticed in three species, the above-mentioned H. micracanthum and also O. bacillaris and P. polonii (Bâ et al, 2011;Ndiaye et al, 2015;.…”