Spermatological characteristics of Pleurogenidae (Digenea) inferred from the ultrastructural study ofPleurogenes claviger,Pleurogenoides mediansandProsotocus confusus

Abstract

The present work constitutes the first ultrastructural analysis of the spermatozoon in the Pleurogenidae, with the study of three species belonging to three of the 16 genera included in this family, namely Pleurogenes claviger, Pleurogenoides medians and Prosotocus confusus. The mature spermatozoa of these pleurogenids present two axonemes of the 9+“1” trepaxonematan pattern, a nucleus, two mitochondria, two bundles of parallel cortical microtubules, external ornamentation, spine-like bodies and granules of glycogen. The organization of these characters in the sperm cell is similar in the three species. Thus, the anterior spermatozoon extremity is filiform and a continuous and submembranous layer of parallel cortical microtubules surrounds the axonemes at their anterior end. The posterior spermatozoon extremity exhibits the second axoneme and corresponds to the Cryptogonimidean type of Quilichini et al. (2010). Slight differences were noted between the spermatozoon of P. confusus and those of the two remaining species in the location of mitochondria.

Spermatological characters of the digenean Lecithostaphylus retroflexus (Molin, 1859) (Microphalloidea: Zoogonidae), a parasite of the teleost fish Belone belone gracilis

“…It is also worthy to note that the axonemes of the L. retroflexus are surrounded by a continuous and submembranous layer of parallel cortical microtubules at their anterior end, whose organization is also reported in D. brusinae (Levron et al, 2004a), M. jourdanei , Pleurogenes claviger, Pleurogenoides medians and Prosotocus confusus (Miquel et al, 2013), Brandesia turgida (Bruňanská et al, 2014) or Postorchigenes gymnesicus (Gracenea et al, 1997). A similar structure was reported in numerous digenean species (Bakhoum, 2012).…”

“…A periodicity of these elements along the sperm cell is observed and estimated as 1 m in O. furcatus, Fasciola gigantica and Nicolla testiobliquum (Miquel et al, 2000;Ndiaye et al, 2004;Quilichini et al, 2007a), 0.7 m in Poracanthium furcatum (Levron et al, 2004b) or 0.6 m in Nicolla wisniewskii (Quilichini et al, 2007c) or 0.5-0.6 m P. claviger (Miquel et al, 2013). However, in L. retroflexus like other species (Miquel et al, 2013) it was not possible to evaluate the periodicity spine-like bodies. Considering all these aspects, this character will be of great interest to the elucidation of the relationships between digeneans at the family level.…”

Ultrastructure of the spermatozoon of Helicometroides atlanticus (Digenea, Monorchiidae), an intestinal parasite of Parapristipoma octolineatum (Pisces, Teleostei) in Senegal

“…Miquel et al, 2013;Bruňanská et al, 2014). Their locations along the spermatozoon vary according to the species.…”

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.…”