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At least 379 records · Page 21Linked to original sources
PubMed2001

Four new genera and five new species of lecanicephalideans (Cestoda: Lecanicephalidea) from elasmobranchs in the Gulf of California, Mexico.

A total of 53 spiral intestines from 3 species of rays collected in the Gulf of California, Baja, Mexico, was examined for cestodes of the order Lecanicephalidea. Four new genera and 5 new species were discovered as a result of this study. These are Aberrapex senticosus n. gen., n. sp., from Myliobatis californica, Paraberrapex manifestus n. gen., n. sp., from Squatina californica and Healyum harenamica n. gen., n. sp., Healyum pulvis n. sp. and Quadcuspibothrium francisi n. gen., n. sp., from Mobula japanica. Aberrapex n. gen. and Paraberrapex n. gen. can be distinguished from all other lecanicephalidean genera based on the lack of an apical structure (pars apicalis) on their scolex. Aberrapex n. gen. can be distinguished from Paraberrapex n. gen. based on the presence of an external seminal vesicle, a vagina positioned lateral rather than medial in the proglottid, and an ovary that is tetralobed rather than bilobed in cross section. Healyum n. gen. and Quadcuspibothrium n. gen. are unique among lecanicephalidean genera, including Aberrapex n. gen. and Paraberrapex n. gen., in their possession of a trilobed ovary in cross section. Quadcuspibothrium n. gen. can be distinguished from Healyum n. gen. based on its unique shape of the acetabula, which are diamond-shaped. The 2 species of Healyum n. gen. can be distinguished from one another based on the dimensions and the shape of the scolex, the diameter of the suckerlike acetabula, as well as the shape of the spiniform microtriches on the acetabular rims. Discobothrium arrhynchum is transferred to the genus Aberrapex n. gen. and the original description of this species is emended to include details of the vas deferens and the uterine duct and uterus. The microtrich patterns of the 5 new species and Aberrapex arrhynchum n. comb. are described. These are the first records of tapeworms of the Lecanicephalidea from the Gulf of California. Squatina californica and Mobula japanica represent new host records for lecanicephalidean tapeworms. The ordinal diagnosis of the Lecanicephalidea by Euzet (1994) is emended to include these 4 new genera.

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PubMed2001

Identity of Cysticercoides menidiae Chandler, 1935 (Cestoda: Dilepididae).

Cysticercoides menidiae Chandler, 1935, described as a metacestode of an unknown dilepidid cestode from the intestinal wall and mesenteries of the silversides Menidia menidia (Pisces: Atherinidae), from Galveston Bay, Texas, was found to be conspecific with Ascodilepis transfuga (Krabbe, 1869), a tapeworm described from the spoonbill. Platalea ajaja Linnaeus (syn. Ajaja ajaja), from Brazil. Consequently. C. menidiae becomes a junior synonym of A. transfuga.

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PubMed2001

Phenotypic modification of roach (Rutilus rutilus L.) infected with Ligula intestinalis L. (Cestoda: Pseudophyllidea).

In European freshwater, cyprinid fish may be heavily infected by plerocercoids of the pseudophyllidea cestode Ligula intestinalis (L.). During their development, these parasites grow rapidly to a large size in the fish's body cavity, characteristically distending the abdomen. In this study, the influence of this tapeworm on roach (Rutilus rutilus L.) morphology was analyzed. Forty-five infected and 45 uninfected roach were collected from the Lavernose-Lacasse gravel pit in Toulouse, south western France and examined for 40 morphological measurements to study phenotypic modification of the body and 14 bilateral characters for an analysis of asymmetry. Results indicate that the degree of bilateral asymmetry does not change between infected and uninfected roach, despite the strong host-morphological modifications such as deformation of the abdomen, fin displacements at the level of the tail, and sagging of the vertebral column. The intensity of abdominal distension and fish morphology changes depends on the total parasite biomass present. Differences were observed in morphology at different levels of infection, which relate to established effects of L. intestinalis on the physiology and behavior of intermediate hosts. These morphological changes induced by the parasite could increase trophic transmission to the definitive avian hosts.

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PubMed2001

Monticellia ophisterni n. sp. (Cestoda: Monticelliidae) from the swamp-eel Ophisternon aenigmaticum (Synbranchiformes) from Mexico.

Monticellia ophisterni n. sp. is described from the swamp-eel Ophisternon aenigmaticum Rosen and Greenwood (Synbranchiformes: Synbranchidae) from Lake Catemaco, Veracruz, Mexico. The new species is placed into Monticellia because of the cortical position of the testes, ovary, and uterus. It differs from other Monticellia species (with the exception of Monticellia magna (Rego, Santos and Silva, 1974)) in the position of longitudinal musculature that crosses the vitelline follicles, making them paramuscular. The new species can be distinguished from M. magna--which possesses a similar number of testes (107-139), paramuscular vitelline follicles, and numerous gland cells distributed between the apex of the scolex and suckers--in the position of the genital pore (8-21% vs. 19-27%), in the presence of a weak internal longitudinal musculature, in the arrangement of the testes in the median field, and in the absence of a vaginal sphincter. This is the first proteocephalidean tapeworm reported from a synbranchid fish and the first species of Monticellia found in North America.

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PubMed2002

Effects of concurrent infections on Hymenolepis diminuta (Cestoda) and Moniliformis dubius (Acanthocephala). I. General effects and comparison with crowding. 1961.

Hymenolepis diminuta developing in the presence of Moniliformis dubius are lighter, shorter, have a lower average weight:length ratio, and are limited to the posterior part of the intra-intestinal range they occupy in single infections. M. dubius in the concurrent infections are lighter, possibly shorter, have a lower average weight:length ratio, and tend to attach further anterior than in single infections. No effects were noted on the percent recovery of either helminth. Highly significant regressions of the wet weight, length, and weight:length ratio of H. diminuta and M. dubius on the number of larvae administered in single infections have been demonstrated. The weight and length of the H. diminuta, and the weight and weight:length ratios of the M. dubius, from concurrent infections were significantly lower than values predicted for single-species infections with a comparable number of worms. In crowded single-species infections, the distribution of attachment points of the H. diminuta is extended to include the anterior three-fourths of the intestine; in concurrent infections the tapeworms are limited to the posterior part of this range. Under crowded conditions, the M. dubius extend their linear intestinal distribution only slightly, all of the acanthocephalans attaching in the anterior half of the small intestine; in concurrent infections the acanthocephalans tend to be limited to the anterior part of this range. The distributional limitations in concurrent infections and the similarities between the effects of concurrent infection and crowding suggest that similar mechanisms, i.e., competition, possibly for carbohydrate, may be involved in the production of the effects of concurrent infection.

Acanthocephala↗
PubMed2004

Phylogenetic analysis on genera of Corallobothriinae (Cestoda: Proteocephalidea) from North American ictalurid fishes, using partial sequences of the 28s ribosomal gene.

Partial sequences of the 28S rDNA (ribosomal gene) were obtained from a total of 11 populations of 5 species (in 3 genera) of North American corallobothriine proteocephalideans. These included Corallobothrium fimbriatum (3 populations), Corallobothrium parafimbriatum (1 population), Corallotaenia minutia (1 population), Megathylacoides giganteum (2 populations), and Megathylacoides lamothei (4 populations). These sequences were used in a phylogenetic analysis to test the monophyly of Corallobothriinae and to investigate the interrelationships of the North American species. The results indicate that Corallobothriinae, as conventionally understood, is not monophyletic and that only the North American corallobothriines, parasites of ictalurid catfishes, form a monophyletic group. Corallobothrium parafimbriatum is sister taxon to a clade that includes Corallotaenia intermedia and C. minutia and not to its congener C. fimbriatum. Also, M. giganteum from Mexico appears to be more closely related to M. lamothei than to its conspecific in Canada. This and the amount of sequence divergence indicate possible cryptic speciation in its endemic host, the Lerma catfish, Ictalurus dugesi.

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PubMed2003

Taxonomic status of Choanoscolex lamothei García-Prieto, 1990 (Cestoda: Proteocephalidea) using morphological and molecular evidence.

The taxonomic status of Choanoscolex lamothei, a proteocephalidean tapeworm described from the catfish Ictalurus meridionalis (= I. furcatus) from Oaxaca, Mexico, was evaluated on the basis of morphological examination of types and freshly collected specimens from the type host and partial sequences of the large subunit (28S) ribosomal DNA. This study revealed that C. lamothei is a species of Megathylacoides (Proteocephalidae: Corallobothriinae) because of the medullary position of the genitalia (entirely cortical in Choanoscolex), the presence of semispherical sphincters on the suckers, a follicular ovary, and the alternating position of the vagina. Megathylacoides lamothei n. comb. differs from congeneric species in lacking an apical organ and in the number (130-208) of testes. Molecular data confirm the position of M. lamothei within Megathylacoides, which contains species parasitizing ictalurid fishes in North America.

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PubMed2004

Occurrence of Proteocephalus tetrastomus (Rudolphi, 1810) (Cestoda: Proteocephalidea) in larval rainbow smelt (Osmerus mordax) in North America: identification of a potential pathogen confirmed.

A morphological evaluation and genetic analysis (sequencing of ITS2 region of rDNA) of proteocephalidean cestodes from rainbow smelt (Osmerus mordax) in the Saint Lawrence Estuary, Canada, has shown their conspecificity with Proteocephalus tetrastomus, a specific parasite of smelt (Osmeridae), previously known only from northern Europe, Russia, and Japan. The parasite occurs only in larval, but not adult, smelt in the Saint Lawrence Estuary. Prevalence of larval smelt infection was 42% (n = 50), mean intensity 2.1 +/- 2.4 and mean abundance 1.1 +/- 1.0.

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PubMed2004

Bathycestus brayi n. gen. and n. sp. (Cestoda: Pseudophyllidea) from the deep-sea fish Notacanthus bonaparte in the northeastern Atlantic.

Bathycestus brayi n. gen., n. sp. (Pseudophyllidea: Triaenophoridae) is proposed to accommodate a new cestode from a deep-sea fish, the shortfin spine eel Notacanthus bonaparte (Notacanthiformes: Notacanthidae), from the northeastern Atlantic. The new genus is placed in the Triaenophoridae because it possesses a uterine pore on the ventral surface, a marginal genital pore, and a follicular vitellaria. Bathycestus most closely resembles Eubothrioides, Fistulicola, Probothriocephalus, and Pseudeubothrioides, which have also an unarmed scolex, a single set of genital organs per proglottid, an unarmed cirrus, cortical vitellaria, and a compact rather dendritic ovary. It differs from these genera by combination of the following features: a sagittate scolex with a weakly developed apical disc and free posterior margins of bothria, no neck, a long cirrus sac, reaching to the median third of proglottids and angled anteromedially in its proximal part, the posterior position of the vagina in relation to the cirrus sac, the testes in 2 lateral fields confluent postovarially, circumcortical vitellaria continuous longitudinally, and unoperculate eggs. Bathycestus brayi n. sp. is the first cestode to be described from a deep-sea fish of the genus Notacanthus.

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PubMed2004

A paraphyly of the genus Bothriocephalus Rudolphi, 1808 (Cestoda: Pseudophyllidea) inferred from internal transcribed spacer-2 and 18S ribosomal DNA sequences.

Phylogenetic relationships between Bothriocephalus species from freshwater and marine teleosts from different geographical regions were studied using internal transcribed spacer-2 and partial 18S ribosomal DNA. The analyses revealed a paraphyly of Bothriocephalus with respect to the genera Polyonchobothrium, Anantrum, and Clestobothrium. The freshwater species Bothriocephalus claviceps, B. acheilognathi, and Bothriocephalus sp. from Dorosoma petenense formed a well-supported monophyletic cluster, with Polyonchobothrium at its base. In contrast, the type species, B. scorpii, clustered within a distinct lineage formed by a heterogeneous assemblage of marine species, Clestobothrium crassiceps and Anantrum tortum, and the freshwater species B. cf. japonicus. This shows that the current morphology-based classification is unlikely to reflect the phylogenetic relationships within this group and will require a thorough revision.

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PubMed2006

Two new species of Paraorygmatobothrium (Cestoda: Tetraphyllidea) from weasel sharks (Carcharhiniformes: Hemigaleidae) of Australia and Borneo.

Two new species of Paraorygmatobothrium Ruhnke, 1994, P. janineae n. sp. and P. kirstenae n. sp., are described from the spiral intestine of 2 shark species of the Family Hemigaleidae: Hemigaleus microstoma and Hemipristis elongata. The 2 new cestode species differ from other members of Paraorygmatobothrium in vitelline follicle distribution and possession of a cephalic peduncle. The 2 new species differ from 1 another in total length, maximum width, scolex size, number of proglottids per strobila, and number of testes per proglottid. The generic diagnosis of Paraorygmatobothrium is emended to include the new species. The results of this study extend the distribution of Paraorygmatobothrium to include the carcharhinid shark family Hemigaleidae.

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PubMed2006

Australicola pectinatus n. gen. and n. sp. (Cestoda: Pseudophyllidea) from the deep-sea fish Beryx splendens from Tasmania.

Australicola pectinatus n. gen., n. sp. (Pseudophyllidea: Triaenophoridae) is proposed to accommodate a new cestode from a deep-sea fish, the splendid alfonsino, Beryx splendens Lowe, 1834 (Beryciformes: Berycidae), from the Pacific coast of Tasmania. The new genus is placed in the Triaenophoridae, because it possesses a ventral uterine pore, marginal genital pore, and follicular vitellarium. Australicola is characterized by possessing a massive strobila with very short and wide, markedly craspedote proglottids; vitelline follicles forming a transverse equatorial band; a very deep and narrow genital atrium; a wide, convoluted vaginal canal; and unoperculate eggs. Australicola most closely resembles Eubothrium Nybelin, 1922 and Probothriocephalus Campbell, 1979 in having an unarmed scolex, an unarmed cirrus, the vagina anterior to the cirrus-sac, and cortical vitellaria. It differs from these 2 genera, in addition to the characteristics listed above, in possessing a dendritic rather than an entire ovary. Australicola pectinatus n. sp. is the third cestode described from B. splendens.

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PubMed2005

A new species of Acanthobothrium (Cestoda: Tetraphyllidea: Onchobothriidae) from the ocellate river stingray, Potamotrygon motoro (Chondrichthyes: Potamotrygonidae), in Argentina.

Examination of the spiral intestines of 44 freshwater stingrays, Potamotrygon motoro, from tributary rivers of the Parana River in Argentina, allowed for the collection of specimens of an undescribed species of Acanthobothrium. Acanthobothrium ramiroi n. sp. can be distinguished from all other congeners by the combination of the following characters: asymmetrical hooks (medial and lateral hooks conspicuously different in size and form, with axial prong of medial hooks stouter than abaxial prong), hook size (total length of medial hooks up to 242 microm, total length of lateral hooks up to 239 microm), bothridia not fused to the scolex proper at posterior ends, worm size (51-84 mm long), and the presence of a conspicuous vaginal sphincter. The new species is different from all other species of Acanthobothrium in freshwater potamotrygonids, except Acanthobothrium terezae, in having conspicuous asymmetrical hooks. The main differences that allow for the distinction between A. ramiroi and A. terezae include hook size, the way the bothridia are attached to the scolex proper, and the shape of the older gravid segments. The discovery of a new species of Acanthobothrium from a potamotrygonid extends our understanding of the diversity of the genus in freshwater stingrays in South America.

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PubMed2006

Three new species of Rhinebothrium (Cestoda: Tetraphyllidea) from the freshwater whipray, Himantura chaophraya, in Malaysian Borneo.

Three new Rhinebothrium Linton, 1890 species, R. kinabatanganensis n. sp., R. megacanthophallus n. sp., and R. abaiensis n. sp., collected from the spiral intestines of 6 freshwater whiprays (Himantura chaophraya, Dasyatidae) in the Kinabatangan River, Malaysian Borneo, are described. This is the first record of cestodes from the Kinabatangan River and from H. chaophraya. The new Rhinebothrium species are differentiated from the 34 valid Rhinebothrium species in addition to 2 species, Echeneibothrium hui Tseng, 1933 and E. oligotesticularis Subramaniam, 1940 that are herein transferred to Rhinebothrium. Each of the new species was examined with light and scanning electron microscopy. Two of the new species possess cilia on their bothridia, which have not previously been reported for members of this genus.

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PubMed2006

Spermiogenesis and sperm ultrastructure of Cyathocephalus truncatus (Pallas, 1781) Kessler, 1868 (Cestoda: Spathebothriidea).

Spermiogenesis and sperm ultrastructure of adult Cyathocephalus truncatus, a member of presumably basal group of "true" cestodes (Eucestoda), have been examined for the first time by using transmission electron microscopy. The process of sperm formation corresponds in basic pattern to that of the Pseudophyllidea. In addition, the 2 pairs of electron-dense attachment zones are present in median cytoplasmic process of C. truncatus. However, mature spermatozoa of C. truncatus differ significantly from those of the pseudophyllideans, especially in the morphology of the proximal and distal spermatozoon extremities. The proximal extremity of the mature spermatozoon lacks a crested body, which is present in more derived cestodes and some pseudophyllideans. The distal end of the mature spermatozoa exhibits different morphology in the gametes from testes and those from receptaculum seminis. New for the Eucestoda is a finding that a lateral cytoplasmic extension creates the distal end of the spermatozoa from testes, resembling sperm of some Monogenea and Digenea. In contrast, the distal extremity of the spermatozoa from receptaculum seminis contains only a nucleus. Despite the above-mentioned peculiarities, the ultrastructural data on sperm/spermiogenesis suggest close relationships of the Spathebothriidea and Pseudophyllidea.

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PubMed2006

Cellular organization of the oncosphere of Mosgovoyia ctenoides (Cestoda: Anoplocephalidae).

The ultrastructure of the infective oncosphere of the cestode Mosgovoyia ctenoides (Anoplocephalidae) is described. The surface of the infective oncosphere is covered by a thin cytoplasmic layer of tegument connected by a narrow cytoplasmic process with the binucleate subtegumental cell, situated deeper in the body. Below the basal matrix of the cytoplasmic layer of the tegument are situated wide bands of the peripheral, somatic musculature responsible for body movements. The 3 pairs of hooks and their muscles form a complex hook muscle system, responsible for coordinated hook action. Five major types of cells have been distinguished: (1) a binucleate subtegumental cell, (2) a binucleate penetration gland, (3) 2 nerve cells, (4) numerous somatic cells, and (5) about 6 germinative cells. The approximate number of cells is 24 (26 nuclei, including 2 syncytial structures). The results of this study, when compared with other published reports from other cestode taxa, support previous hypotheses that the progressive reduction of oncosphere cells is an adaptive feature in cestode evolution.

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PubMed2003

Seasonal and yearly population dynamics of two exotic helminths, Camallanus coti (Nematoda) and Bothriocephalus acheilognathi (Cestoda), parasitizing exotic fishes in Waianu Stream, O'ahu, Hawaii.

Exotic poeciliid fishes introduced into Hawaiian freshwaters are responsible for the introduction of several exotic parasites, of which the most important are Camallanus cotti and Bothriocephalus acheilognathi in terms of potential disease threat to native stream fishes. This roundworm and tapeworm are the most prevalent and abundant freshwater fish helminths in Hawaiian streams. This study examined the seasonal and yearly population structure of C. cotti and B. acheilognathi to determine if the tropical Hawaiian environment characterized by low climatic variability permits continuous opportunities for parasite transmission regardless of time of year. Camallanus cotti displayed seasonal differences in prevalence and mean abundance, whereas B. acheilognathi did not. Camallanus cotti prevalence and mean abundance were higher in the Hawaiian summer (47.7%, 0.79) than in winter (25.8%, 0.36). A seasonal relationship of C. cotti levels is likely explained by extensive rains associated with the Hawaiian winter season, which may act to decrease parasite transmission by flushing infected poeciliid hosts, intermediate copepod hosts, and possibly free-living infective worm stages downstream. Bothriocephalus acheilognathi displayed low prevalence and mean abundance in both summer (4.0%, 0.06) and winter (6.5%, 0.07), and it may be difficult to detect seasonal changes due to these low levels. Camallanus cotti prevalence and mean abundance remained relatively constant from the summer of 1995 to the summer of 1999, indicating that levels of this roundworm are stable in Waianu Stream. Whereas B. acheilognathi prevalence and mean abundance were low during the summer of 1995 and the summer of 1997, a dramatic peak in prevalence and mean abundance was observed in the summer of 1998 (41.2%, 1.06), with levels decreasing sharply in the summer of 1999 (4.4%, 0.07). It appears that B. acheilognathi also is present in stable populations at low levels, even though levels rose sharply during a single year.

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