The western chimpanzee (Pan troglodytes verus) is "Critically Endangered" due to a gradual decrea... more The western chimpanzee (Pan troglodytes verus) is "Critically Endangered" due to a gradual decrease of its population and a continuous degradation of their habitats. Niokolo Koba National Park is considered an important biodiversity area in West Africa and has high conservation value for western chimpanzees. However, Niokolo Koba National Park has been inscribed on the World Heritage list as being in Danger since 2007 due to anthropogenic factors. Over the last 40 years, only sporadic and shortterm studies on the ecology and behavior of chimpanzees in the park have occurred. For this reason, we studied the nesting ecology of a putative chimpanzee community in the Antenna zone. We also identified sympatric medium and large mammals using a camera trap. Chimpanzees mostly used Hexalobus monopetalus for nesting, followed by Pterocarpus erinaceus. Nest heights in the Antenna zone were lower than they are in Assirik, and outside the park at Fongoli and Diaguiri sites despite the presence of potential predators in the park. Predator presence influences nesting height behavior. These data deepen our knowledge about chimpanzees in Senegal, and are useful for the management plan of the park and will contribute to an action plan for their conservation there.
While West African chimpanzees (Pan troglodytes verus) were elevated to Critically Endangered sta... more While West African chimpanzees (Pan troglodytes verus) were elevated to Critically Endangered status by the IUCN in 2016 as a result of significant population declines in recent decades, little is known about the population in Senegal. We surveyed the West African chimpanzees outside protected areas in the Kedougou region of southeastern Senegal between November 2014 and July 2015 using recce walks (n = 57, totalling 300 km of pedestrian survey distance) in potential chimpanzee habitats. We recorded direct observations of chimpanzees or indices of chimpanzee activity, such as sleeping nests, footprints and faeces. We accumulated 21 direct contacts with chimpanzees and recorded 3489 chimpanzee nests. We mapped the distribution of chimpanzee sleeping sites and indicators of anthropogenic activity by regional administrative units to facilitate species management and conservation planning in the immediate future. In addition, we identified the habitats and tree species used by chimpanzees to construct their nests in order to explore nesting tree preferences. Chimpanzees used almost 40 tree species in the Kedougou region but 84% of nests were associated with eight tree species, namely Pterocarpus erinaceus, Diospyros mespiliformis, Anogeissus leiocarpus, Hexalobus monopetalus, Cola cordifolia, Lannea sp., Parkia biglobosa and Piliostigma thonningii. Among these eight nesting tree species, 60% of the corresponding nests were located in three species: P. erinaceus, D. mespiliformis and A. leiocarpus. Chimpanzees nested more often in woodland habitat than in gallery forests, although the latter accounts for only a small percentage of available habitat. This study is the most geographically extensive survey of chimpanzees in Senegal to date, broadening our knowledge of the species' northwestern-most distribution in West Africa.
The present study contributes to our knowledge of the ultrastructure of spermatogenesis and the s... more The present study contributes to our knowledge of the ultrastructure of spermatogenesis and the spermatozoon of parasitic platyhelminthes. We emphasize those ultrastructural characters that are most useful for the systematics, taxonomy and phylogeny of this group. Because of this, we have studied the ultrastructure of spermiogenesis and the spermatozoon of seven platyhelminthes. These were: four digeneans (Scaphiostomum palaearcticum, Fasciola hepatica, Fasciola gigantica and Notocotylus neyrai) and three cyclophyllideans (Joyeuxiella pasqualei, Joyeuxiella echinorhynchoides and Taenia parva). The study of S. palaearcticum is the first ultrastructural analysis of a representative of the subfamily Ityogoniminae (Brachylaimidae). Our observations of the spermatozoon of N. neyrai are the first study of a species of the Notocotylidae family. We compared Fasciola hepatica isolated from Bos taurus and Rattus rattus from the mouth of Fango river (Corsica, Mediterranean sea) with F. gigantica isolated from Bos indicus in Senegal. Moreover, we studied the external morphology of the spermatozoon in F. hepatica by both scanning (SEM) and whole mount transmission electron microscopy (TEM). Finally, the pattern of distribution of tubuline in the microtubular cytoskeleton of F. hepatica is also analysed by means of monoclonal anti-tubulins (anti-α-tubulin, anti-β-tubulin, antiα-acetylated tubulin and anti-α-tyrosinated tubulin). We established the general pattern of spermiogenesis for the genus Joyeuxiella and also for the family Dipylidiidae. In the case of T. parva, the present results also contribute to the establishment of the ultrastructural features of the spermatozoon of Taeniidae species. Features of the digeneans such as the ornamentation of the cell membrane, the cytoplasmic expansions and the spine-like bodies are reviewed and discussed. Concerning the cestodes, the formation of the periaxonemal sheath is described for the first time during spermiogenesis in Joyeuxiella spp. Moreover, certain aspects of the spermiogenesis patterns, such as striated rootlets or flagellar rotation are discussed.
The wide biodiversity and economic importance of digeneans have motivated a great deal of researc... more The wide biodiversity and economic importance of digeneans have motivated a great deal of research in the last decade, focussing on their phylogenetic positions. Molecular research was instrumental for our understanding of phylogeny in the Digenea, but spermatological studies have also provided many results, which are potentially useful for phylogeny; however, the complete spermatological data set has never been reviewed in a whole phylogenetic perspective. Spermatological data are now available for more than 100 species, belonging to 15 superfamilies and 46 families. In this paper, we try to summarize the current knowledge about sperm structure in the digeneans and propose a classification of digenean spermatozoa into five basic models. The main ultrastructural characters used are (1) the type of axoneme, (2) the lateral expansion, (3) the association 'external ornamentation of the plasma membrane + cortical microtubules', (4) the field of cortical microtubules and its numb...
The ultrastructural organization of the spermatozoon of the digenean Lecithostaphylus retroflexus... more The ultrastructural organization of the spermatozoon of the digenean Lecithostaphylus retroflexus (Microphalloidea: Zoogonidae) was described. Alive digeneans were collected from Belone belone gracilis (Teleostei: Belonidae), caught from the Gulf of Gabès in Chebba (Tunisia). The mature spermatozoon of L. retroflexus exhibits two axonemes of different lengths with the 9+'1' Trepaxonematan pattern, a nucleus, two mitochondria, two bundles of parallel cortical microtubules and granules of glycogen. Additionally, the spermatozoon of L. retroflexus shows type 2 of the external ornamentation according to Quilichini et al. (2011), spine-like bodies and a continuous and submembranous layer of parallel cortical microtubules surrounding the axonemes at their anterior end. Moreover, the morphology of the posterior spermatozoon extremity in L. retroflexus corresponds to the fasciolidean type according to Quilichini et al. (2010).
The ultrastructural organization of the spermatozoon of the digenean Tergestia acanthocephala (Gy... more The ultrastructural organization of the spermatozoon of the digenean Tergestia acanthocephala (Gymnophalloidea: Fellodistomidae) is described. Live digeneans were collected from Belone belone gracilis (Teleostei: Belonidae), caught off the Gulf of Gabès in Chebba (Tunisia). The mature spermatozoon of T. acanthocephala exhibits the general pattern described in numerous digeneans, characterized by the presence of two axonemes of the different length of the 9+'1' pattern of the Trepaxonemata, a nucleus, two mitochondria, two bundles of parallel cortical microtubules, external ornamentation, spine-like bodies and granules of glycogen. Moreover, the morphology of the posterior spermatozoon extremity in T. acanthocephala corresponds to the fasciolidean type of Quilichini et al. (2010a).
In the present paper, we describe the ultrastructure of the spermatozoon of the notocotylid Notoc... more In the present paper, we describe the ultrastructure of the spermatozoon of the notocotylid Notocotylus noyeri (Joyeux, 1922) by means of transmission electron microscopy. The mature spermatozoon of N. noyeri exhibits the general pattern described in the majority of digeneans: two axonemes of the 9 + "1" pattern of the Trepaxonemata, nucleus, mitochondria, parallel cortical microtubules, spine-like bodies and ornamentation of the plasma membrane. The glycogenic nature of the electron-dense granules was evidenced applying the test of Thiéry. The ultrastructural features of the spermatozoon of N. noyeri present some differences in relation to those of the Pronocephalidea described until now, but confirm a general pattern for the Notocotylidae, namely a spermatozoon with two mitochondria and an anterior region with ornamentation of the plasma membrane associated with spine-like bodies. The posterior extremity of the spermatozoon exhibits only some microtubules after the disorganisation of the second axoneme. The present study confirms that some ultrastructural characters of the sperm cell such as the presence or absence of lateral expansions, the number of mitochondria and the morphology of both anterior and posterior spermatozoon extremities are useful for phylogenetic purposes within the Pronocephaloidea. Thus, unlike notocotylids, pronocephalids exhibit external ornamentation and a lateral expansion in the anterior spermatozoon region. Moreover, notocotylid spermatozoa present two mitochondria, whereas pronocephalid spermatozoa exhibit a single mitochondrion. Finally, pronocephalids are characterised by a type 2 posterior spermatozoon extremity, whereas notocotylids exhibit a type 3 posterior spermatozoon extremity.
This study provides the first ultrastructural data of spermatozoa in the genus Lecithochirium. Th... more This study provides the first ultrastructural data of spermatozoa in the genus Lecithochirium. The spermatozoa of L. microstomum (from Trichiurus lepturus in Senegal) and L. musculus (from Anguilla anguilla in Corsica) exhibit the general pattern described in the great majority of the Digenea, namely two axonemes with the 9 + ''1'' pattern typical of the Trepaxonemata, one mitochondrion, a nucleus, parallel cortical microtubules and external ornamentation of the plasma membrane. Spermatozoa of L. microstomum and L. musculus have some specific features such as the presence of a reduced number of cortical microtubules arranged on only one side of the spermatozoon, the lack of spine-like bodies and expansion of the plasma membrane. The external ornamentation of the plasma membrane entirely covers the anterior extremity of the spermatozoa. The ultrastructure of the posterior extremity of the spermatozoa corresponds to the pattern previously described in the Hemiuridae, characterized by only singlets of the second axoneme. A particularity of these spermatozoa is the organization of the microtubule doublets of the second axoneme around the nucleus in the posterior part of the spermatozoon.
This work describes the first ultrastructural results on spermiogenesis and on the mature spermat... more This work describes the first ultrastructural results on spermiogenesis and on the mature spermatozoon of Dicrocoelium hospes (Trematoda, Digenea) collected in Bos indicus from Senegal (Africa). Examination of this species was processed by TEM. Spermiogenesis follows the general pattern found in the digenean, but reveals a particularity consisting of the appearance of glycogen granules in the late spermatids within the testes. The mature spermatozoon possesses five distinct regions and presents all features found in Digenea gametes: two axonemes, mitochondria, nucleus and parallel cortical microtubules. However, several characters allow us to distinguish D. hospes from other digenetic trematodes within the Dicrocoeliidae family. In fact, we observed several structures that are absent in the other species of Dicrocoeliidae studied until now, such as: a cytoplasmic expansion, extramembranar ornamentation, spine-like bodies and two parallel mitochondria in the mature sperm. Moreover, additional particular characteristics were observed in this species in both extremities of the spermatozoon. This work produced new data on the ultrastructure of this trematode family which may be useful for phylogenetic purposes.
The current study was designed to increase the spermatological ultrastructural database on Digene... more The current study was designed to increase the spermatological ultrastructural database on Digenea, thus contributing to the future establishment of phylogenetic relationships within this group based on ultrastructural characteristics of both spermiogenesis and spermatozoa. Spermiogenesis in Elstia stossichianum begins with the formation of a differentiation zone containing two centrioles, two striated rootlets, a nucleus, several mitochondria and an intercentriolar body constituted by seven electron-dense layers. Each centriole develops into a free flagellum growing orthogonally to the median cytoplasmic process. Proximo-distal fusion of the flagella with the median cytoplasmic process occurs after flagellar rotation. Both nucleus and mitochondria migrate before the complete proximo-distal fusion of both flagella with the median cytoplasmic process. Finally, the constriction of the ring of arched membranes gives rise to the young spermatozoon. The mature spermatozoon of E. stossich...
Chez Scaphiostomum palaearcticum, la spermiogenèse commence par la formation d'une zone de différ... more Chez Scaphiostomum palaearcticum, la spermiogenèse commence par la formation d'une zone de différentiation qui comprend deux centrioles séparés par un corps intercentriolaire et associé chacun à une racine striée. Elle est caractérisée par une rotation flagellaire asynchrone, suivie d'une fusion proximo-distale des deux flagelles avec l'expansion cytoplasmique médiane. La migration du noyau vers l'expansion cytoplasmique médiane a lieu avant la fusion proximo-distale. Par contre, la migration de la mitochondrie vers l'expansion cytoplasmique médiane intervient avant la fusion du deuxième flagelle. Des zones d'attachement, disposées sur la face interne de la membrane cytoplasmique de l'expansion médiane sont également observées avant la fusion de cette dernière avec les flagelles. Le spermatozoïde mature de S. palaearcticum, est filiforme, effilé à ses deux extrémités et présente toutes les caractéristiques décrites chez le gamète mâle des digènes : présence de deux axonèmes, de mitochondrie, d'un noyau et de deux rangées parallèles de microtubules corticaux. Cependant, le spermatozoïde de S. palaearcticum présente d'autres caractéristiques qui le distinguent du spermatozoïde des autres digènes.
Trematoda, Digenea, Fasciolidae) est décrite en microscopie électronique à balayage (SEM) et à tr... more Trematoda, Digenea, Fasciolidae) est décrite en microscopie électronique à balayage (SEM) et à transmission (TEM). Chez F. hepatica, la spermiogenèse suit le modèle général déjà décrit chez les Digenea. Cependant, une rotation flagellaire d'environ 120º est décrite pour la première fois chez cette espèce et chez les Digenea. Le spermatozoïde mature de F. hepatica est une cellule filiforme d'environ 275 µm de long. La technique de « whole mount » et des observations au microscope électronique à balayage nous ont permis de démontrer la disposition spiralée des axonèmes le long du corps spermatique. Le spermatozoïde présente les mêmes caractéristiques ultrastructurales que F. gigantica. Les caractères les plus intéressants de ce gamète mâle sont les suivants : l'expansion cytoplasmique dorso-latérale, l'ornementation externe de la membrane cytoplasmique et les corps épineux. La localisation de la tubuline au niveau du cytosquelette microtubulaire de F. hepatica est aussi analysée au moyen d'anticorps monoclonaux (anti-α-tubuline, anti-β-tubuline, anti-α-tubuline acétylée et anti-α-tubuline tyrosinée). Ainsi les doublets des axonèmes et les microtubules corticaux sont marqués par ces anti-tubulines. Par contre, aucun de ces anticorps n'a permis le marquage de l'élément central de l'axonème 9 + '1' des Trepaxonemata.
The ultrastructural characters of the mature spermatozoon of Opechona bacillaris (Molin, 1859) (D... more The ultrastructural characters of the mature spermatozoon of Opechona bacillaris (Molin, 1859) (Digenea, Lepocreadiidae) a parasite of Scomber colias Gmelin, 1789 (Scombridae) off the coast of Dakar (Senegal).-Acta Zoologica (Stockholm) 96: 91-98. This study presents the ultrastructure of the mature spermatozoon of Opechona bacillaris, a digenean belonging to the family Lepocreadiidae. The sperm cell of O. bacillaris exhibits the general pattern described in most of the Lepocreadioidea: two axonemes of the 9 + '1' pattern of the Trepaxonemata, mitochondria, a cortical mitochondrion, a nucleus, electron-dense material in the anterior extremity of the spermatozoon, external ornamentation of the plasma membrane with associated spinelike bodies, and granules of glycogen. However, particularities of O. bacillaris are the simultaneous presence in the anterior extremity of the spermatozoon of the electron-dense material, a mitochondrion, and the absence of cortical microtubules. In the Lepocreadiidae, we describe for the first time in O. bacillaris spinelike bodies associated with the external ornamentation of the plasma membrane and two mitochondria. The first mitochondrion is moniliform and composed of a mitochondrial cord with joined mitochondrial bulges. The second mitochondrion shows a regular form. The posterior tip of the spermatozoon has only singlets to owing to the disorganization of the second axoneme and granules of glycogen as occurs in Hypocreadium caputvadum, the other studied species of the family Lepocreadiidae.
Spermiogenesis and spermatozoon ultrastructure of the dilepidid cestode Molluscotaenia crassiscol... more Spermiogenesis and spermatozoon ultrastructure of the dilepidid cestode Molluscotaenia crassiscolex (von Linstow, 1890), an intestinal parasite of the common shrew Sorex araneus
The spermiogenesis process in Wardula capitellata begins with the formation of a differentiation ... more The spermiogenesis process in Wardula capitellata begins with the formation of a differentiation zone containing two centrioles associated with striated rootlets and an intercentriolar body. Each centriole develops into a free flagellum orthogonal to a median cytoplasmic process. Later these flagella rotate and become parallel to the median cytoplasmic process, which already exhibits two electron-dense areas and spinelike bodies before its proximodistal fusion with the flagella. The final stage of the spermiogenesis is characterized by the constriction of the ring of arched membranes, giving rise to the young spermatozoon, which detaches from the residual cytoplasm. The mature spermatozoon of W. capitellata presents most of the classical characters reported in digenean spermatozoa such as two axonemes of different lengths of the 9 + “1” trepaxonematan pattern, nucleus, mitochondrion, two bundles of parallel cortical microtubules and granules of glycogen. However, some peculiarities ...
Heterakis is a genus of parasitic nematodes, the majority of which are found in ground-feeding bi... more Heterakis is a genus of parasitic nematodes, the majority of which are found in ground-feeding birds and only rarely in mammals. The best-known species is Heterakis spumosa, a parasite associated with the cosmopolitan invasive rodent Rattus rattus of Asiatic origin. Heterakis dahomensis was described in 1911 as a parasite of the Gambian giant rat (Cricetomys gambianus) from Benin (Africa), subsequently synonymized to H. spumosa by Hall (1916). The study of helminths in African rodents is scarce and patchy. Since the original description of H. dahomensis, there have been only a few reports from Africa of species belonging to the genus Heterakis and the validity of this species has never in fact been confirmed or rejected. In the present study individual Heterakis spp. were collected from C. gambianus from Senegal. The morphological data taken point to differences between Heterakis dahomensis and H. spumosa, specifically in the number of tail papillae in males and in the vulva cuticul...
The western chimpanzee (Pan troglodytes verus) is "Critically Endangered" due to a gradual decrea... more The western chimpanzee (Pan troglodytes verus) is "Critically Endangered" due to a gradual decrease of its population and a continuous degradation of their habitats. Niokolo Koba National Park is considered an important biodiversity area in West Africa and has high conservation value for western chimpanzees. However, Niokolo Koba National Park has been inscribed on the World Heritage list as being in Danger since 2007 due to anthropogenic factors. Over the last 40 years, only sporadic and shortterm studies on the ecology and behavior of chimpanzees in the park have occurred. For this reason, we studied the nesting ecology of a putative chimpanzee community in the Antenna zone. We also identified sympatric medium and large mammals using a camera trap. Chimpanzees mostly used Hexalobus monopetalus for nesting, followed by Pterocarpus erinaceus. Nest heights in the Antenna zone were lower than they are in Assirik, and outside the park at Fongoli and Diaguiri sites despite the presence of potential predators in the park. Predator presence influences nesting height behavior. These data deepen our knowledge about chimpanzees in Senegal, and are useful for the management plan of the park and will contribute to an action plan for their conservation there.
While West African chimpanzees (Pan troglodytes verus) were elevated to Critically Endangered sta... more While West African chimpanzees (Pan troglodytes verus) were elevated to Critically Endangered status by the IUCN in 2016 as a result of significant population declines in recent decades, little is known about the population in Senegal. We surveyed the West African chimpanzees outside protected areas in the Kedougou region of southeastern Senegal between November 2014 and July 2015 using recce walks (n = 57, totalling 300 km of pedestrian survey distance) in potential chimpanzee habitats. We recorded direct observations of chimpanzees or indices of chimpanzee activity, such as sleeping nests, footprints and faeces. We accumulated 21 direct contacts with chimpanzees and recorded 3489 chimpanzee nests. We mapped the distribution of chimpanzee sleeping sites and indicators of anthropogenic activity by regional administrative units to facilitate species management and conservation planning in the immediate future. In addition, we identified the habitats and tree species used by chimpanzees to construct their nests in order to explore nesting tree preferences. Chimpanzees used almost 40 tree species in the Kedougou region but 84% of nests were associated with eight tree species, namely Pterocarpus erinaceus, Diospyros mespiliformis, Anogeissus leiocarpus, Hexalobus monopetalus, Cola cordifolia, Lannea sp., Parkia biglobosa and Piliostigma thonningii. Among these eight nesting tree species, 60% of the corresponding nests were located in three species: P. erinaceus, D. mespiliformis and A. leiocarpus. Chimpanzees nested more often in woodland habitat than in gallery forests, although the latter accounts for only a small percentage of available habitat. This study is the most geographically extensive survey of chimpanzees in Senegal to date, broadening our knowledge of the species' northwestern-most distribution in West Africa.
The present study contributes to our knowledge of the ultrastructure of spermatogenesis and the s... more The present study contributes to our knowledge of the ultrastructure of spermatogenesis and the spermatozoon of parasitic platyhelminthes. We emphasize those ultrastructural characters that are most useful for the systematics, taxonomy and phylogeny of this group. Because of this, we have studied the ultrastructure of spermiogenesis and the spermatozoon of seven platyhelminthes. These were: four digeneans (Scaphiostomum palaearcticum, Fasciola hepatica, Fasciola gigantica and Notocotylus neyrai) and three cyclophyllideans (Joyeuxiella pasqualei, Joyeuxiella echinorhynchoides and Taenia parva). The study of S. palaearcticum is the first ultrastructural analysis of a representative of the subfamily Ityogoniminae (Brachylaimidae). Our observations of the spermatozoon of N. neyrai are the first study of a species of the Notocotylidae family. We compared Fasciola hepatica isolated from Bos taurus and Rattus rattus from the mouth of Fango river (Corsica, Mediterranean sea) with F. gigantica isolated from Bos indicus in Senegal. Moreover, we studied the external morphology of the spermatozoon in F. hepatica by both scanning (SEM) and whole mount transmission electron microscopy (TEM). Finally, the pattern of distribution of tubuline in the microtubular cytoskeleton of F. hepatica is also analysed by means of monoclonal anti-tubulins (anti-α-tubulin, anti-β-tubulin, antiα-acetylated tubulin and anti-α-tyrosinated tubulin). We established the general pattern of spermiogenesis for the genus Joyeuxiella and also for the family Dipylidiidae. In the case of T. parva, the present results also contribute to the establishment of the ultrastructural features of the spermatozoon of Taeniidae species. Features of the digeneans such as the ornamentation of the cell membrane, the cytoplasmic expansions and the spine-like bodies are reviewed and discussed. Concerning the cestodes, the formation of the periaxonemal sheath is described for the first time during spermiogenesis in Joyeuxiella spp. Moreover, certain aspects of the spermiogenesis patterns, such as striated rootlets or flagellar rotation are discussed.
The wide biodiversity and economic importance of digeneans have motivated a great deal of researc... more The wide biodiversity and economic importance of digeneans have motivated a great deal of research in the last decade, focussing on their phylogenetic positions. Molecular research was instrumental for our understanding of phylogeny in the Digenea, but spermatological studies have also provided many results, which are potentially useful for phylogeny; however, the complete spermatological data set has never been reviewed in a whole phylogenetic perspective. Spermatological data are now available for more than 100 species, belonging to 15 superfamilies and 46 families. In this paper, we try to summarize the current knowledge about sperm structure in the digeneans and propose a classification of digenean spermatozoa into five basic models. The main ultrastructural characters used are (1) the type of axoneme, (2) the lateral expansion, (3) the association 'external ornamentation of the plasma membrane + cortical microtubules', (4) the field of cortical microtubules and its numb...
The ultrastructural organization of the spermatozoon of the digenean Lecithostaphylus retroflexus... more The ultrastructural organization of the spermatozoon of the digenean Lecithostaphylus retroflexus (Microphalloidea: Zoogonidae) was described. Alive digeneans were collected from Belone belone gracilis (Teleostei: Belonidae), caught from the Gulf of Gabès in Chebba (Tunisia). The mature spermatozoon of L. retroflexus exhibits two axonemes of different lengths with the 9+'1' Trepaxonematan pattern, a nucleus, two mitochondria, two bundles of parallel cortical microtubules and granules of glycogen. Additionally, the spermatozoon of L. retroflexus shows type 2 of the external ornamentation according to Quilichini et al. (2011), spine-like bodies and a continuous and submembranous layer of parallel cortical microtubules surrounding the axonemes at their anterior end. Moreover, the morphology of the posterior spermatozoon extremity in L. retroflexus corresponds to the fasciolidean type according to Quilichini et al. (2010).
The ultrastructural organization of the spermatozoon of the digenean Tergestia acanthocephala (Gy... more The ultrastructural organization of the spermatozoon of the digenean Tergestia acanthocephala (Gymnophalloidea: Fellodistomidae) is described. Live digeneans were collected from Belone belone gracilis (Teleostei: Belonidae), caught off the Gulf of Gabès in Chebba (Tunisia). The mature spermatozoon of T. acanthocephala exhibits the general pattern described in numerous digeneans, characterized by the presence of two axonemes of the different length of the 9+'1' pattern of the Trepaxonemata, a nucleus, two mitochondria, two bundles of parallel cortical microtubules, external ornamentation, spine-like bodies and granules of glycogen. Moreover, the morphology of the posterior spermatozoon extremity in T. acanthocephala corresponds to the fasciolidean type of Quilichini et al. (2010a).
In the present paper, we describe the ultrastructure of the spermatozoon of the notocotylid Notoc... more In the present paper, we describe the ultrastructure of the spermatozoon of the notocotylid Notocotylus noyeri (Joyeux, 1922) by means of transmission electron microscopy. The mature spermatozoon of N. noyeri exhibits the general pattern described in the majority of digeneans: two axonemes of the 9 + "1" pattern of the Trepaxonemata, nucleus, mitochondria, parallel cortical microtubules, spine-like bodies and ornamentation of the plasma membrane. The glycogenic nature of the electron-dense granules was evidenced applying the test of Thiéry. The ultrastructural features of the spermatozoon of N. noyeri present some differences in relation to those of the Pronocephalidea described until now, but confirm a general pattern for the Notocotylidae, namely a spermatozoon with two mitochondria and an anterior region with ornamentation of the plasma membrane associated with spine-like bodies. The posterior extremity of the spermatozoon exhibits only some microtubules after the disorganisation of the second axoneme. The present study confirms that some ultrastructural characters of the sperm cell such as the presence or absence of lateral expansions, the number of mitochondria and the morphology of both anterior and posterior spermatozoon extremities are useful for phylogenetic purposes within the Pronocephaloidea. Thus, unlike notocotylids, pronocephalids exhibit external ornamentation and a lateral expansion in the anterior spermatozoon region. Moreover, notocotylid spermatozoa present two mitochondria, whereas pronocephalid spermatozoa exhibit a single mitochondrion. Finally, pronocephalids are characterised by a type 2 posterior spermatozoon extremity, whereas notocotylids exhibit a type 3 posterior spermatozoon extremity.
This study provides the first ultrastructural data of spermatozoa in the genus Lecithochirium. Th... more This study provides the first ultrastructural data of spermatozoa in the genus Lecithochirium. The spermatozoa of L. microstomum (from Trichiurus lepturus in Senegal) and L. musculus (from Anguilla anguilla in Corsica) exhibit the general pattern described in the great majority of the Digenea, namely two axonemes with the 9 + ''1'' pattern typical of the Trepaxonemata, one mitochondrion, a nucleus, parallel cortical microtubules and external ornamentation of the plasma membrane. Spermatozoa of L. microstomum and L. musculus have some specific features such as the presence of a reduced number of cortical microtubules arranged on only one side of the spermatozoon, the lack of spine-like bodies and expansion of the plasma membrane. The external ornamentation of the plasma membrane entirely covers the anterior extremity of the spermatozoa. The ultrastructure of the posterior extremity of the spermatozoa corresponds to the pattern previously described in the Hemiuridae, characterized by only singlets of the second axoneme. A particularity of these spermatozoa is the organization of the microtubule doublets of the second axoneme around the nucleus in the posterior part of the spermatozoon.
This work describes the first ultrastructural results on spermiogenesis and on the mature spermat... more This work describes the first ultrastructural results on spermiogenesis and on the mature spermatozoon of Dicrocoelium hospes (Trematoda, Digenea) collected in Bos indicus from Senegal (Africa). Examination of this species was processed by TEM. Spermiogenesis follows the general pattern found in the digenean, but reveals a particularity consisting of the appearance of glycogen granules in the late spermatids within the testes. The mature spermatozoon possesses five distinct regions and presents all features found in Digenea gametes: two axonemes, mitochondria, nucleus and parallel cortical microtubules. However, several characters allow us to distinguish D. hospes from other digenetic trematodes within the Dicrocoeliidae family. In fact, we observed several structures that are absent in the other species of Dicrocoeliidae studied until now, such as: a cytoplasmic expansion, extramembranar ornamentation, spine-like bodies and two parallel mitochondria in the mature sperm. Moreover, additional particular characteristics were observed in this species in both extremities of the spermatozoon. This work produced new data on the ultrastructure of this trematode family which may be useful for phylogenetic purposes.
The current study was designed to increase the spermatological ultrastructural database on Digene... more The current study was designed to increase the spermatological ultrastructural database on Digenea, thus contributing to the future establishment of phylogenetic relationships within this group based on ultrastructural characteristics of both spermiogenesis and spermatozoa. Spermiogenesis in Elstia stossichianum begins with the formation of a differentiation zone containing two centrioles, two striated rootlets, a nucleus, several mitochondria and an intercentriolar body constituted by seven electron-dense layers. Each centriole develops into a free flagellum growing orthogonally to the median cytoplasmic process. Proximo-distal fusion of the flagella with the median cytoplasmic process occurs after flagellar rotation. Both nucleus and mitochondria migrate before the complete proximo-distal fusion of both flagella with the median cytoplasmic process. Finally, the constriction of the ring of arched membranes gives rise to the young spermatozoon. The mature spermatozoon of E. stossich...
Chez Scaphiostomum palaearcticum, la spermiogenèse commence par la formation d'une zone de différ... more Chez Scaphiostomum palaearcticum, la spermiogenèse commence par la formation d'une zone de différentiation qui comprend deux centrioles séparés par un corps intercentriolaire et associé chacun à une racine striée. Elle est caractérisée par une rotation flagellaire asynchrone, suivie d'une fusion proximo-distale des deux flagelles avec l'expansion cytoplasmique médiane. La migration du noyau vers l'expansion cytoplasmique médiane a lieu avant la fusion proximo-distale. Par contre, la migration de la mitochondrie vers l'expansion cytoplasmique médiane intervient avant la fusion du deuxième flagelle. Des zones d'attachement, disposées sur la face interne de la membrane cytoplasmique de l'expansion médiane sont également observées avant la fusion de cette dernière avec les flagelles. Le spermatozoïde mature de S. palaearcticum, est filiforme, effilé à ses deux extrémités et présente toutes les caractéristiques décrites chez le gamète mâle des digènes : présence de deux axonèmes, de mitochondrie, d'un noyau et de deux rangées parallèles de microtubules corticaux. Cependant, le spermatozoïde de S. palaearcticum présente d'autres caractéristiques qui le distinguent du spermatozoïde des autres digènes.
Trematoda, Digenea, Fasciolidae) est décrite en microscopie électronique à balayage (SEM) et à tr... more Trematoda, Digenea, Fasciolidae) est décrite en microscopie électronique à balayage (SEM) et à transmission (TEM). Chez F. hepatica, la spermiogenèse suit le modèle général déjà décrit chez les Digenea. Cependant, une rotation flagellaire d'environ 120º est décrite pour la première fois chez cette espèce et chez les Digenea. Le spermatozoïde mature de F. hepatica est une cellule filiforme d'environ 275 µm de long. La technique de « whole mount » et des observations au microscope électronique à balayage nous ont permis de démontrer la disposition spiralée des axonèmes le long du corps spermatique. Le spermatozoïde présente les mêmes caractéristiques ultrastructurales que F. gigantica. Les caractères les plus intéressants de ce gamète mâle sont les suivants : l'expansion cytoplasmique dorso-latérale, l'ornementation externe de la membrane cytoplasmique et les corps épineux. La localisation de la tubuline au niveau du cytosquelette microtubulaire de F. hepatica est aussi analysée au moyen d'anticorps monoclonaux (anti-α-tubuline, anti-β-tubuline, anti-α-tubuline acétylée et anti-α-tubuline tyrosinée). Ainsi les doublets des axonèmes et les microtubules corticaux sont marqués par ces anti-tubulines. Par contre, aucun de ces anticorps n'a permis le marquage de l'élément central de l'axonème 9 + '1' des Trepaxonemata.
The ultrastructural characters of the mature spermatozoon of Opechona bacillaris (Molin, 1859) (D... more The ultrastructural characters of the mature spermatozoon of Opechona bacillaris (Molin, 1859) (Digenea, Lepocreadiidae) a parasite of Scomber colias Gmelin, 1789 (Scombridae) off the coast of Dakar (Senegal).-Acta Zoologica (Stockholm) 96: 91-98. This study presents the ultrastructure of the mature spermatozoon of Opechona bacillaris, a digenean belonging to the family Lepocreadiidae. The sperm cell of O. bacillaris exhibits the general pattern described in most of the Lepocreadioidea: two axonemes of the 9 + '1' pattern of the Trepaxonemata, mitochondria, a cortical mitochondrion, a nucleus, electron-dense material in the anterior extremity of the spermatozoon, external ornamentation of the plasma membrane with associated spinelike bodies, and granules of glycogen. However, particularities of O. bacillaris are the simultaneous presence in the anterior extremity of the spermatozoon of the electron-dense material, a mitochondrion, and the absence of cortical microtubules. In the Lepocreadiidae, we describe for the first time in O. bacillaris spinelike bodies associated with the external ornamentation of the plasma membrane and two mitochondria. The first mitochondrion is moniliform and composed of a mitochondrial cord with joined mitochondrial bulges. The second mitochondrion shows a regular form. The posterior tip of the spermatozoon has only singlets to owing to the disorganization of the second axoneme and granules of glycogen as occurs in Hypocreadium caputvadum, the other studied species of the family Lepocreadiidae.
Spermiogenesis and spermatozoon ultrastructure of the dilepidid cestode Molluscotaenia crassiscol... more Spermiogenesis and spermatozoon ultrastructure of the dilepidid cestode Molluscotaenia crassiscolex (von Linstow, 1890), an intestinal parasite of the common shrew Sorex araneus
The spermiogenesis process in Wardula capitellata begins with the formation of a differentiation ... more The spermiogenesis process in Wardula capitellata begins with the formation of a differentiation zone containing two centrioles associated with striated rootlets and an intercentriolar body. Each centriole develops into a free flagellum orthogonal to a median cytoplasmic process. Later these flagella rotate and become parallel to the median cytoplasmic process, which already exhibits two electron-dense areas and spinelike bodies before its proximodistal fusion with the flagella. The final stage of the spermiogenesis is characterized by the constriction of the ring of arched membranes, giving rise to the young spermatozoon, which detaches from the residual cytoplasm. The mature spermatozoon of W. capitellata presents most of the classical characters reported in digenean spermatozoa such as two axonemes of different lengths of the 9 + “1” trepaxonematan pattern, nucleus, mitochondrion, two bundles of parallel cortical microtubules and granules of glycogen. However, some peculiarities ...
Heterakis is a genus of parasitic nematodes, the majority of which are found in ground-feeding bi... more Heterakis is a genus of parasitic nematodes, the majority of which are found in ground-feeding birds and only rarely in mammals. The best-known species is Heterakis spumosa, a parasite associated with the cosmopolitan invasive rodent Rattus rattus of Asiatic origin. Heterakis dahomensis was described in 1911 as a parasite of the Gambian giant rat (Cricetomys gambianus) from Benin (Africa), subsequently synonymized to H. spumosa by Hall (1916). The study of helminths in African rodents is scarce and patchy. Since the original description of H. dahomensis, there have been only a few reports from Africa of species belonging to the genus Heterakis and the validity of this species has never in fact been confirmed or rejected. In the present study individual Heterakis spp. were collected from C. gambianus from Senegal. The morphological data taken point to differences between Heterakis dahomensis and H. spumosa, specifically in the number of tail papillae in males and in the vulva cuticul...
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