Ultrastructure of mature spermatozoa of three Bucephalidae (Prosorhynchus longisaccatus, Rhipidocotyle khaliliandBucephalus margaritae) and phylogenetic implications

Abstract

We describe here the mature spermatozoa of three species of bucephalids, namely Bucephalus margaritae, Rhipidocotyle khalili and Prosorhynchus longisaccatus. This study provides the first ultrastructural data on the genera Bucephalus and Rhipidocotyle and enabled us to confirm the model of the mature spermatozoon in the Bucephalinae. The spermatozoon exhibits two axonemes with the 9 + “1” pattern of the Trepaxonemata, one of which is very short, lateral expansion, external ornamentation of the plasma membrane located in the anterior extremity of the spermatozoon and associated with cortical microtubules, spine-like bodies, a mitochondrion, and a nucleus. The maximum number of cortical microtubules is located in the anterior part of the spermatozoon. However, more studies are needed to elucidate if spine-like bodies are present in all the Bucephalinae or not. In the Prosorhynchinae, the mature spermatozoon exhibits a similar ultrastructural pattern. Some differences are observed, particularly the axoneme lengths and the arrangement of the spine-like bodies. The posterior extremity of the spermatozoon in the Bucephalinae exhibits only the nucleus, but prosorhynchines have microtubules.

A comparative study of the ultrastructural characteristics of the mature spermatozoa of two fellodistomidsTergestia clonacanthaandT. laticollisand contribution to the phylogenetic knowledge of the Gymnophalloidea

“…Overall, the authors found a similar general pattern. Table 1 shows that the same spermatozoon type (according to Bakhoum et al [ 7 ]) has usually been found for species of the same genus: type III for Holorchis micracanthum [ 3 ] and H. pycnoporus [ 12 ]; type V for Prosorhynchus aculeatus and [ 18 ] P. longisaccatus [ 26 ]; type V for the Diplodiscidae Diplodiscus amphichrus [ 10 ] and D. subclavatus [ 5 ]; type V for Fasciola gigantica [ 22 ] and F. hepatica [ 21 ]; type II for Lecithochirium microstomum [ 23 ] and L. musculus [ 23 ]; type III for the Lepocreadiidae Bianium arabicum [ 30 ] and B. plicitum [ 30 ]; type IV for the Opisthorchiidae Opisthorchis felineus [ 32 ] and O. viverrini [ 13 ]; type IV for the Opecoelidae Allopodocotyle pedicellata [ 6 ] and A. tunisiensis [ 15 ], and type III for the Opecoelidae Nicolla testiobliquum [ 27 ] and N. wisniewskii [ 28 ]. Nevertheless, some differences have been observed between spermatozoa of species belonging to the same genus like the Notocotylidae Notocotylus neyrai [ 20 ] (undefined type) and N. noyeri [ 24 ] (type IV) concerning the location of the external ornamentation; the Opecoeloidea Helicometra epinepheli [ 29 ] (type III) and Helicometra fasciata [ 16 ] (undefined type) concerning especially the presence/absence of external ornamentation; and the Zoogonidae Lecithostaphylus parexocoeti [ 4 ] (undefined type) and L. retroflexus [ 14 ] (type IV) concerning the location of the external ornamentation.…”

“…Some families have never been studied, while some genera have already been the subject of several studies. Among these genera, we considered: the Aephnidiogenidae Holorchis [ 3 , 12 ], the Bucephalidae Prosorhynchus [ 18 , 26 ], the Dicrocoeliidae Dicrocoelium [ 1 , 8 ], the Diplodiscidae Diplodiscus [ 5 , 10 ], the Fasciolidae Fasciola [ 21 , 22 ], the Hemiuridae Lecithochirium [ 23 ], the Lepocreadiidae Bianium [ 30 ], the Notocotylidae Notocotylus [ 20 , 24 ], the Opecoelidae Allopodocotyle [ 6 , 15 ], Helicometra [ 16 , 29 ] and Nicolla [ 27 , 28 ], the Opisthorchiidae Opisthorchis [ 19 , 32 ], and the Zoogonidae Lecithostaphylus [ 4 , 14 ].…”

New spermatological characteristics in the Hemiuroidea inferred from the ultrastructure of the spermatozoon of Gonocerca phycidis a stomach parasite of Gephyroberyx darwinii (Teleostei: Trachichthyidae) off the Senegal coast

“…A lateral expansion has been described at the anterior extremity of the spermatozoon of ve superfamilies of Digenea. These are the Echinostomatoidea, the Microscaphidioidea, the Paramphistomoidea, the Pronocephaloidea and the Bucephaloidea (Bakhoum et al 2017a; Kacem and Miquel 2018; Ndiaye et al 2019). In the present work, we describe for the rst time its presence in a Hemiuroidea.…”

Sperm characters of the digeneanNephrotrema truncatum(Troglotrematidae): a kidney parasite ofCrocidura russula(Soricidae) and their phylogenetic significance

“…In the last decade, the potential of this source of characters for phylogenetic purposes in the Digenea has been analysed by various authors Quilichini et al 2010aQuilichini et al , 2011Bakhoum et al 2017). To date, there are more or less complete spermatological studies in a large number of digeneans belonging to 18 superfamilies and more than 50 families (Justine 1995;Bakhoum et al 2017;Kacem and Miquel 2018;Ndiaye et al 2018). In the Gorgoderoidea published works on the ultrastructure of the spermatozoon involve the Acanthocolpidae, Allocreadiidae, Dicrocoeliidae, Paragonimidae and Troglotrematidae families (Robinson and Halton 1982;Orido 1988;Cifrian et al 1993;Agostini et al 2005;Miquel et al 2006;Quilichini, Foata, Orsini et al 2007;Bakhoum, Quilichini, Justine et al 2015;Bakhoum, Quilichini, Miquel et al 2015).…”