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SEM of adult Wenyonia virilis. Fig. 2. Scolex with fully extended introvert. Note the faint trace of an apical ring and also the flattened longitudinal ridges separated by shallow furrows. Fig. 3. Surface of the end of an extended introvert showing the corrugated tegument. Fig. 4. Scolex with an introvert partially retracted through the apical ring. Observe the prominent ridges and deep furrows. Fig. 5. Apical view of a partially retracted introvert that is separated from the apical ring by a conspicuous fold. Fig. 6. Scolex apex with a deep, U-shaped apical pouch formed when the introvert is fully retracted. Fig. 7. Scolex showing well-defined longitudinal ridges separated from each other by deep furrows. The apical ring is at the tip of the scolex; the introvert itself is not visible. Fig. 8A. View of a stretching dorsoventrally flattened scolex. Ridges and furrows are especially prominent. Within the shallow sucker-like depression formed by the apical ring and introvert is a dorsoventral slit or fold formed by the retracted introvert. B. Enlarged view of introvert
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Development and morphology of the scolex and mode of attachment of Wenyonia virilis Woodland, 1923, a caryophyllaeid cestode from the silurid Nile fish Synodontis schall (Bloch et Schneider, 1801), were studied by means of light and scanning electron microscopy (SEM). Scolex and genital primordia
changes through four stages of juvenile development...
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Context 1
... with little trace of the apical ring, so evident when the introvert is fully retracted (Fig. 6). A par- tially everted introvert forms a crease that separates it from the apical ring (Figs 4 and 5). As the central portion of the intro-vert retracts, a shallow sucker-like structure with a deep slit or fold is formed in a dorsoventral orientation (Fig. 8). Finally, the slit widens to form a deep cavity or apical pouch made by the fully retracted introvert (Figs 6 and ...
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... the sucker-like structure surrounding the introvert may appear to be acetabular in nature (Fig. 8), mid-sagittal sections of the scolex show that it is not (Fig. 10A, B). No pro- nounced musculature was found associated with the introvert. However, there appears to be many small, diffuse muscles ( Fig. 10A-C) that, along with similar muscles associated with the ridges, are extensions of the larger bundles of longitudi- nal muscles ...
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... that is separated from the apical ring by a conspicuous fold. Fig. 6. Scolex apex with a deep, U-shaped api- cal pouch formed when the introvert is fully retracted. Fig. 7. Scolex showing well-defined longitudinal ridges separated from each other by deep furrows. The apical ring is at the tip of the scolex; the introvert itself is not visible. Fig. 8A. View of a stretching dorsoventrally flattened scolex. Ridges and furrows are especially prominent. Within the shallow sucker-like depression formed by the apical ring and introvert is a dorsoventral slit or fold formed by the retracted introvert. B. Enlarged view of introvert intestinal mucosa. Juveniles of stages 1 and 2 were free in ...
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... the most anterior end of the scolex of W. virilis is the terminal introvert. It is a mobile, protrusible structure that lies within an apical ring formed at the confluence of the ridges at the scolex apex (Figs 4, 6 and 8). Kulmatycki (1924) consid- ered that the anterior part of the scolex functions as a kind of primitive suctorial disc. ...
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Citations
... Specimens were preliminary identified using the keys of Scholz et al. (2018), and then further identified using Oros et al. (2010). The developmental stages of specimens from L. aeneus were determined using the designation for the developmental stages of another caryophyllidean, Wenyonia virilis Woodland, 1923, by Ibraheem and Mackiewicz (2006). ...
... An egg was also observed in the female genital pore ( Figure 2E). Using the designation of juveniles of W. virilis by Ibraheem and Mackiewicz (2006), the cestodes collected from L. aeneus were confirmed to be juveniles from stages 2 to 4. A late stage 4 cestode can be seen in Figure 3A, B. Late final stage juveniles (stage 4) were identified by the presence of follicular ovaries, fully differentiated vitelline follicles and testes, numerous wide uterine folds, and fully formed male and female genital pores, that are open to the exterior ( Figure 3E, F). No cercomers were observed. ...
... As noted, none of the cestodes collected from L. aeneus were gravid, but late stage 4 juveniles were observed and thus they may have been on the verge of developing eggs. Unfortunately, the development of juvenile A. huronensis in the definitive host is not well studied, and the present extrapolated interpretation from the work of Ibraheem and Mackiewicz (2006) may be premature. Scholz (1993) studied the development of another caryophyllidean, Khawia baltica Szidat, 1942, and noted that several factors determine the speed of development in the definitive host. ...
Atractolytocestus huronensis Anthony, 1958 has been co-introduced with its cyprinid host Cyprinus carpio Linnaeus, 1758, common carp, to several continents. This cestode was only recently (2012) detected in South Africa and occur in two major river systems. In Africa, A. huronensis has only been reported from C. carpio. During routine parasitological surveys in the Vaal River system in central South
Africa, unidentified cestodes were recorded from common carp at several localities. Using light and scanning electron microscopy, alongside genetic characterisation, they were identified as A. huronensis, greatly expanding the distribution of this parasite in the upper reaches of the Vaal River system and indicating rapid spread
in the system. Thereafter, in November 2020, more caryophyllidean cestodes were detected infecting native smallmouth yellowfish, Labeobarbus aeneus (Burchell, 1822) just below the Vaal Dam wall. They were also morphologically and genetically identified as A. huronensis, indicating a possible new definitive host and spillover
from carp. However, only juvenile worms (up to late stage 4) were detected in L. aeneus, suggesting a paradefinitive or accidental infection. Their pathological effect on the intestine of L. aeneus mimicked that described in acute infections in common carp, with damage limited to the intestinal epithelium and no prominent ulcerations. This apparent mild infection of an indigenous host needs to be monitored. The spillover to L. aeneus appears to be recent as no caryophyllidean cestodes were collected from this host species at the same locality and season the previous year, nor at any of the other well studied sites in the Vaal River system. Chronic infection of L. aeneus may still develop and indicate that the near threatened largemouth yellowfish, Labeobarbus kimberleyensis (Gilchrist & Thompson, 1913), may be at risk as well.
... The most prevalent cestode in the clariids in this study was W. virilis, whose prevalence is most likely related to their diet. Wenyonia species have been reported to use tubificid worms such as Tubifex tubifex as intermediate host, and these worms are likely food for clariids (Ibraheem and Mackiewicz, 2006); however, the stomach contents of fish were not examined or analysed in this study to ascertain this. The annelid acquires infection by ingesting embryonated eggs of this cestode and when the annelid is ingested by a fish (definitive host), they in turn become infected (Ibraheem and Mackiewicz, 2006). ...
... Wenyonia species have been reported to use tubificid worms such as Tubifex tubifex as intermediate host, and these worms are likely food for clariids (Ibraheem and Mackiewicz, 2006); however, the stomach contents of fish were not examined or analysed in this study to ascertain this. The annelid acquires infection by ingesting embryonated eggs of this cestode and when the annelid is ingested by a fish (definitive host), they in turn become infected (Ibraheem and Mackiewicz, 2006). Copepods have also been reported to serve as intermediate hosts of Wenyonia species (Kuchta et al 2008). ...
Four catfish (Siluriformes) species comprising two clariids, Heterobranchus bidorsalis (65) and Heterobranchus longifilis (15) and two claroteids, Auchenoglanis occidentalis (31) and Chrysichthys auratus (19) from River Galma Zaria, Nigeria, were examined for gastrointestinal cestodes between May 2016 and February 2017. Helminths recovered were stained, dehydrated, cleared and mounted in Canada balsam for microscopic examination. A total of seven cestode species were recovered from the clariids and claroteids. The cestodes were distributed among the fish examined as follows: in C. auratus: Wenyonia longicauda (26.32%), W. virilis (10.53%), and W. minuta (5.26%); in H. bidorsalis: W. acuminata (3.08%), W. virilis (18.46%), Monobothrioides woodlandi (6.15%), Proteocephalus sp. (1.54%) and Tetracampos ciliotheca (4.62%); in H. longifilis: M. woodlandi (6.67%), W. longicauda (6.67%) and W. acuminata (6.67%). Prevalence of cestode infection in C. auratus was higher in the wet than in the dry season; however, prevalence of infection in H. longifilis and H. bidorsalis was higher in the dry than in the wet season. The prevalence was higher in male than in female H. longifilis while higher in female than in male C. auratus and H. bidorsalis. Prevalence decreased with increase in standard length of C. auratus, H. longifilis and H. bidorsalis. A seemingly posteriorly deformed W. minuta was recovered from C. auratus. None of the 31 A. occidentalis examined in this study was infected by cestodes. All the fish used in this study were collected mostly on the basis of availability. It is therefore recommended that larger sample of assorted sizes be obtained, especially of H. longifilis (15) and C. auratus (19), of which very few specimens were examined during the period of this study to obtain a clearer picture of infection by the cestodes from RiverGalma, Zaria, Nigeria. Keywords: Cestodes; catfish; clariid claroteid; siluriformes; infection; prevalence; intensity.
... The isolated nematodes were kept in glycerin alcohol (70% ethanol plus 5% glycerol) then washed in 70% ethanol, cleared in lacto phenol and mounted in glycerol gelatin. Collected parasites were identified according to Khalil (1964), Arai (1989), Scholz and Salgado-Maldonado (2000), Moravec and Van As (2004), Ibraheem and Mackiewicz (2006), Scholz et al. (2009), and Moravec & Scholz (2017). ...
... Khalil and Polling (1997) reported three species of Wenyonia from the Nile: W. minuta; W. acuminate and W. virilis from Egypt. The morphological characteristics of the Wenyonia virilis parasite isolated in this study resembled the previously described W. virilis (Ibraheem andMackiewicz, 2006 andBjoern et al., 2011). Eighteen species of Proteocephalidean tapeworms have been described from freshwater fishes in Africa The morphological description of Rhadinorhnchus sp. reported in the present study was similar to that described by (Arandas Rego, 1987 andArai, 1989) and it is the first time to detect it from Synodotis schall so it may be new host record. ...
... Khalil and Polling (1997) reported three species of Wenyonia from the Nile: W. minuta; W. acuminate and W. virilis from Egypt. The morphological characteristics of the Wenyonia virilis parasite isolated in this study resembled the previously described W. virilis (Ibraheem andMackiewicz, 2006 andBjoern et al., 2011). Eighteen species of Proteocephalidean tapeworms have been described from freshwater fishes in Africa The morphological description of Rhadinorhnchus sp. reported in the present study was similar to that described by (Arandas Rego, 1987 andArai, 1989) and it is the first time to detect it from Synodotis schall so it may be new host record. ...
This work describes the parasitic infections in wild Synodontis serratus and Synodontis schall from Lake Nasser, Egypt and the histopthological impacts of these parasites on the infected fish. A total number of 100 Synodontis serratus and 100 Synodontis schall were collected alive from several and various localities of the lake during 2018. One cestode: Wenyonia virilis, three nematodes: Cithariniella citharini, Procamallanus laeviconchus and Spirocamallanus pseudospiralis (new locality record) and one zoonotic encysted metacercaria of trematode: Centrocestus formosanus (new hosts record) were identified from both fish species; in addition to, one cestode: Proteocephalus sulcatus and one acanthocephalan: Rhadinorhynchus sp. (new host record) were only recorded from Synodontis schall. The infection rates of examined fish; Synodontis serratus and Synodontis schall were 54% and 78% respectively. This study evaluated clinical signs, postmortem lesions, organ or tissue susceptibility, incidence, intensity of infection, seasonal prevalence and histopathological alterations induced by these parasitic infections. Interestingly, the musculature of the fish was free from any parasitic infections and safe for human consumption provided that the fish would be eviscerated and adequately cooked. This work provides analysis of fish-parasite fauna which is a very helpful tool for implementing control and preventative measures against parasitic diseases especially the zoonotic ones.
... For example, the resemblance between the scolex of the new taxon and that of caryophyllideans such as, for example, Weynonia virilis Woodland, 1923 (e.g. Ibraheem and Mackiewicz 2006) (see Fig. 3C) is striking. Some caryophyllideans, such as Hunterella nodulosa Mackiewicz & McCrae, 1962 have been shown to induce extensive nodules in the mucosa of their host at the site of attachment (e.g. ...
An enigmatic new tapeworm is described from pelagic thresher sharks in México and Taiwan. While lsrRNA (D1-D3) data robustly place it in the Litobothriidea, it bears essentially no morphological resemblance to other members of the order. Instead it superficially resembles the freshwater fish-inhabiting Caryophyllidea. Its scolex consists of a simple dome-shaped scolex proper and an extensive cephalic peduncle housing four distinct tissue types. It is hyperapolytic, thus reproductive anatomy is unknown. Developmental data show typical litobothriideans bear basic elements of their adult scolex upon entering the definitive host, undermining the notion that the new cestode represents a distinct litobothriidean life cycle stage. Scanning electron microscopy revealed the new species shares bands of distinctive microtriches with its congeners. In combination these data justify establishment of Litobothrium aenigmaticum, sp. nov.; the generic, familial and ordinal diagnoses are emended accordingly. Unlike typical litobothriideans, each worm is associated with a mucosal expansion at its attachment site, like those seen in some caryophyllideans. This pathological change may represent a worm-induced host response serving to reinforce attachment of the simple scolex to the mucosa. If so, the convergence of this litobothriidean on a morphology like that seen in the distantly related Caryophyllidea is a result of similarity in mode of attachment.
... Excretory system well developed, with main lateral canals and smaller, medially anastomosed canals; numbers of canals decrease posteriorly; canals open into excretory bladder near posterior extremity. Scolex variable in shape, usually rugomonobothriate (sensu Mackiewicz, 1994, andMackiewicz, 2006), i.e. with deep and/or shallow longitudinal furrows and apical introversion; in most species with transverse band of darkly stained cells demarcating base. Neck portion distinct or absent. ...
... Kulmatycki (1928) reported this species, as Caryophyllaeus niloticus Kulmatycki, 1928, from the same host at Cairo, Egypt and at Omdurman (North Khartoum), Sudan. Numerous records of W. virilis exist, mainly from Egypt (Garo et al., 2000;Al-Bassel, 2003;Ibraheem & Mackiewicz, 2006). This tapeworm was previously found in six species of Synodontis, but as many as seven new definitive hosts are reported in the present study. ...
Tapeworms of the genus Wenyonia Woodland, 1923 (Caryophyllidea: Caryophyllaeidae), parasites of catfishes in Africa, are revised. This revision is based on material from large-scale sampling, in the Democratic Republic of the Congo, Kenya, Senegal and the Sudan between 2006 and 2009, and the examination of all of the type-specimens available. The following six species are considered valid and their redescriptions are provided: Wenyonia virilis Woodland, 1923 (type-species; new synonym W. kainjii Ukoli, 1972); W. acuminata Woodland, 1923; W. longicauda Woodland, 1937; W. minuta Woodland, 1923 (new synonym W. mcconnelli Ukoli, 1972); W. synodontis Ukoli, 1972; and W. youdeoweii Ukoli, 1972. A key to the identification of Wenyonia spp. is provided and numerous new hosts and geographical records are reported. A comparative phylogenetic analysis of partial sequences of the 28S rRNA gene of four species divided the monophyletic genus into two lineages, one represented by W. acuminata and W. minuta and another one composed of W. virilis and W. youdeoweii.
... The order Caryophyllidea, consisting of four families (Balanotaenidae, Capingetidae, Caryophyllaeidae, and Lytocestidae), is presently subjected to extensive and complex studies using morphological, molecular, and also cytogenetic approaches [3,7,[34][35][36][37][38][39][40]. Recent cladistic data suggest that phylogenetic relationships within the order are only partially compatible with the traditional classification and that probably all caryophyllidean families are paraphyletic [3,4]. ...
Karyotype and chromosomal characteristics, i.e. number and location of ribosomal DNA (rDNA) clusters, and sequence variation of the ribosomal internal transcribed spacer 2 (ITS2) were studied in a monozoic (unsegmented) tapeworm, Caryophyllaeides fennica (Caryophyllidea), using conventional and Ag-staining, fluorescent in situ hybridization (FISH) with 18S rDNA probe, and PCR amplification, cloning and sequencing of the complete ribosomal ITS2 spacer. The karyotype of this species was composed of ten pairs of metacentric (m) chromosomes (2n=20). All chromosomes except the pair No. 2 displayed DAPI-positive heterochromatin in centromeric regions. In addition, two distinct interstitial DAPI-positive bands were identified on chromosome pair No. 7. FISH with 18S rDNA probe revealed four clusters of major ribosomal genes situated in the pericentromeric region of the short arms in two pairs of metacentric chromosomes Nos. 8 and 9. Hybridization signals were stronger in the pair No. 8, indicating a higher amount of rDNA repeats at this nucleolar organizer region (NOR). Analysis of 15 ITS2 rDNA sequences (five recombinant clones from each of three individuals) showed 13 structurally different ribotypes, distinguished by 26 nucleotide substitutions and variable numbers and combinations of short repetitive motifs that allowed sorting the sequences into four ITS2 variants. These results contribute to recently published evidence for the intraindividual ribosomal ITS sequence variability in basal tapeworms with multiple rDNA loci and imply that both phenomena may be mutually linked.
... Detailed information on the scolex morphology of the taxa parasitic in cypriniform fish in Central Europe was provided by Scholz (1989), who also used both light and scanning electron microscopy, as did Ibraheem and Mackiewicz (2006), who described the morphology of the scolex of Wenyonia virilis Woodland, 1923, a parasite of the mochokid catfish Synodontis schall (Bloch et Schneider) from Egypt. However, almost none of the descrip-tions of caryophyllidean taxa contain scanning electron micrographs of their scoleces. ...
A comparative study of the scoleces of caryophyllidean tapeworms (Cestoda: Caryophyllidea), parasitic in cypriniform fishes in the Palaearctic Region, was carried out using light and scanning electron microscopy. Three-dimensional pictures of the scoleces of 18 species of caryophyllidean cestodes of the Capingentidae (1 species), Caryophyllaeidae (7) and Lytocestidae (10), and outlines of the scoleces and anterior extent of the testes and vitelline follicles of 19 Palaearctic taxa were documented. Both species of Atractolytocestus Anthony, 1957 possess a bulboacuminate scolex, whereas species of Archigetes Leuckart, 1876 have fossate scoleces of the bothrioloculodiscate type, with loculi, bothrium-like depressions and an apical disc. Breviscolex orientalis Kulakovskaya, 1962, the only member of the Capingentidae, has a cuneiform scolex, as do both taxa of the lytocestid genus Caryophyllaeides Nybelin, 1922. The scoleces of two species of Caryophyllaeus Gmelin, 1790 are flabellate, whereas that of the congeneric C. fimbriceps Annenkova-Chlopina, 1919 is cuneicrispitate. Khawia Hsü, 1935, the most specious Palaearctic genus, with seven taxa that we consider to be valid, has the highest diversity in scolex morphology: semi-bulbate, flabellate, cuneiform, cuneifimbriate, truncated cuneiform-flabellate and festoon-like. Species of Monobothrium Nybelin, 1922 have either a digitiform scolex with widened posterior part or cuneiform, with lateral auricular extensions. Paracaryophyllaeus gotoi (Motomura, 1927) is characteristic in its possessing a bulbate scolex, whereas Paraglaridacris limnodrili (Yamaguti, 1934) has a fossate scolex of the bulboloculate type with bothrium-like depressions and feebly developed lateral loculi. Anterior extent of the testes and vitelline follicles and their mutual position show a somewhat higher variability than scolex shape, with intraspecific variation in some taxa, such as Atractolytocestus sagittatus (Kulakovskaya et Akhmerov, 1965), B. orientalis, Khawia armeniaca (Cholodkovsky, 1915) and K. sinensis Hsii, 1935. Based on scolex morphology and relative position of the anterior testes and vitelline follicles, a key is provided to facilitate the routine identification of 20 Palaearctic caryophyllidean taxa.
... Furthermore, one-half of the Wenyonia species have a postovarian region that is greater in length than the preovarian region, a characteristic shared only by the lytocestid Caryoaustralis Mackiewicz et Blair, 1980, from Australia. In addition, the scolex is of the rugomonobothriate type, unique to Wenyonia and Monobothrioides Furhmann et Baer, 1925, both found only in Africa (Ibraheem and Mackiewicz 2006). Finally, from a developmental aspect, it appears that W. virilis "…exhibits less of a tendency toward progenesis than of any other caryophyllid", according to Ibraheem and Mackiewicz (2006: 56). ...
The ultrastructure of spermiogenesis in Wenyonia virilis Woodland, 1923, a caryophyllaeid cestode from the silurid Nile fish Synodontis schall (Bloch et Schneider, 1801), is described by means of transmission electron microscopy (TEM) for the first time. Spermiogenesis
follows the characteristic caryophyllidean type and is initiated by the formation of a differentiation zone. This area, delimited
at its base by a ring of arching membranes and bordered by cortical microtubules, contains two centrioles associated with
typical striated rootlets with a reduced intercentriolar body between them. The apical area of the differentiation zone exhibits
electron-dense material that is present only during the early stages of spermiogenesis. Only one of the centrioles develops
into a free flagellum that grows at an angle of >90° in relation to the cytoplasmic extension. Spermiogenesis is also characterized
by a flagellar rotation and a proximodistal fusion of the flagellum with the cytoplasmic extension. The most interesting features
observed in W virilis are the presence of a reduced, very narrow intercentriolar body and the unique type of flagellar rotation >90°. Results are
compared with those described in two caryophyllideans, Glaridacris catostomi Cooper, 1920 and Khawia armeniaca (Cholodkovski, 1915). Contrary to the original report of Świderski and Mackiewicz (2002), that flagellar rotation has never
been observed in spermiogenesis of G. catostomi, re-assessment of their description and illustrations leads us to conclude that flagellar rotation must logically occur in
that species. The value of various morphological features of sperm in phylogenetic inference is discussed.
Malhotra et al. (2011) described Wenyonia rhincodoni n. sp. a caryophyllaeid cestode from Rhincodon typus (Shark) at west coast of Goa, and considered the cestode to be new to the science of helminthology. Unfortunately, they usedpolythetic division classificatory system applications to substantiate morphometric differences between body organs ofthe species described by them & Wenyonia (acuminata, minuta and virilis) but the description suffers from a numberof lacunae (death inside) specially presence of an intestine in a cestode & hence the present authors have kept thespecies of Malhotra et al. (2011) under enquiry.
Ultrastructural evidence for early intraurerine embryonic development of Wenyonia virilis is presented. At the initial stage of egg formation, the fertilized oocyte or ovum is surrounded by numerous vitellocytes and newly formed eggshell. Individual vitellocytes undergo progressive fusion into a vitelline syncytium. During cleavage divisions, three types of blastomeres are formed: macromeres, mesomeres and micromeres. Two large macromeres contain a large nucleus with spherical nucleolus and numerous small heterochromatin islands dispersed in moderately electron-dense nucleoplasm. The granular cytoplasm shows a few large mitochondria. Medium-sized mesomeres contain a spherical nucleus with numerous heterochromatin islands, adjacent to the nuclear envelope, and a prominent electron-dense nucleolus. Their nuclei are embedded in granular cytoplasm with a few large and numerous small mitochondria and Golgi complexes. The small micromeres are characterized by presence of spherical nucleoli with large areas of highly condensed heterochromatin and a few islands of granular electron-lucent nucleoplasm. Their granular cytoplasm shows a few small lipid droplets and several spherical mitochondria. Majority of micromeres give rise to the hexacanth but many of them also undergo degeneration or apoptosis. Both mesomeres and macromeres are engaged in the formation of the oncospheral envelopes. The outer envelope is formed by a fusion of two macromeres whereas the inner envelope originates from a fusion of mesomeres. The intrauterine eggs of W virilis usually contain an embryo at the early preoncopheral phase of development and possesses three primary envelopes: (1) thick eggshell; (2) thin cytoplasmic layer of the outer envelope and (3) inner envelope. Based on embryonic development, egg type and life-cycle characteristics, caryophyllideans tend to show closer affinities to spathebothriideans than to the former pseudophyllideans.
