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Egg structure and early embryonic development of the aspidogastrean, Rohdella amazonica, a basal trematode, were studied by transmission electron microscopy (TEM) to gain insight into functional, developmental, and phylogenetic characteristics. Gravid worms were removed from the intestine of naturally infected banded puffer fish Colomesus psittacus, collected from the Bay of Marajó, Paracauari River (Pará, Brazil) and processed by standard TEM methods. By the time of pronuclear fusion, the fertilized zygote was already enclosed in a thick, electron-dense pre-operculate eggshell and an underlying layer of vitellocytes that fused into a vitelline syncytium as they were still secreting their shell granules. When cleavage commenced, a small number of macromeres moved to the area just underneath the eggshell, where they fused to form a single syncytial embryonic envelope. Simultaneously, the smaller blastomeres continued to divide as they maintained contact with each other, but remained separate from the vitelline syncytium. Concurrent with these cellular changes, a thickened knob expanded at one pole of the eggshell and began to form an opercular suture. By the time the operculum was fully formed, the vitelline syncytium had mostly degenerated, while the smaller blastomeres had become cohesive as a single mass that preceded the differentiation and morphogenesis of the cotylocidium larva. The general pattern of cleavage and eggshell formation resembles that of other trematodes and polylecithal cestodes, but the single embryonic envelope has been reported only in a few basal taxa. The only other aspidogastrean studied in detail to date is very similar, indicating close phylogenetic affinity and conservatism within this basal neodermatan and neoophoran group.

Species of the eutetrarhynchid genus Hispidorhynchus Schaeffner and Beveridge, 2012 possess an uncinate macrohook on the bothrial surface of the basal swelling of each tentacle. This unique feature of the oncotaxy is only shared with the closely related genus Oncomegas Dollfus, 1929 . A new species of Hispidorhynchus is described from specimens infecting Styracura schmardae (Werner, 1904) (Potamotrygonidae) from the western Caribbean Sea off the coast of Belize and Panama. Hispidorhynchus styracurae n. sp. differs from its 3 congeners in the possession of smaller and narrower bulbs, fewer principle hooks in the metabasal armature, size of the macrohook, and different scolex proportions. Scanning electron microscopy reveals new information on the microthrix morphology of the genus. A diagnostic key for the differentiation of species of Hispidorhynchus is provided. In addition, new host and locality records are reported for Oncomegas wageneri ( Linton, 1890 ) Dollfus, 1929 , collected from Hypanus guttatus (Bloch and Schneider, 1801) (Dasyatidae) off the coast of Maceió, Alagoas (Brazil). This considerably expands the geographical distribution of this species in the western Atlantic Ocean.

The cestode fauna of Squaliolus aliae was examined for the first time following the collection of elasmobranch specimens from Taiwan in 2005, 2013, and 2017. This small shark was found to host 2 tapeworm species. These consist of Acanthobothrium katherineae n. sp., which is new to science and is described herein, and a second species, in the genus Scyphophyllidium, which also appears to be new, but which is represented by insufficient material for formal description. Acanthobothrium katherineae is a category 5 species. It can be distinguished from 5 of the 19 other category 5 species in that it is apolytic, retaining proglottids on its strobila until they are gravid. This new species differs from the remaining 14 category 5 species in its combination of the following features: It is a smaller worm, has fewer than 100 proglottids, has a relatively short cephalic peduncle, and differs in bothridial size and loculus ratio. Sequence data for the D1-D3 region of the 28S rDNA gene were generated for one specimen of A. katherineae. This sequence, along with comparable sequence data for adults of 14 described and 2 undescribed species as well as specimens of 6 undescribed larval members of the genus, was included in a maximum likelihood phylogenetic analysis. The resulting tree places the shark-hosted A. katherineae within a clade of stingray-hosted species, with Acanthobothrium romanowi as its sister taxon. Acanthobothrium katherineae is 1 of only 19 Acanthobothrium species known to parasitize sharks. The tree resulting from this study, which is preliminary given the relatively poor taxon sampling of the diversity in the genus, included 3 of the shark-parasitizing Acanthobothrium species and suggests that all 3 represent host-switching events. This is the first report of an Acanthobothrium species from the family Dalatiidae and the first report of a Scyphophyllidium species from the order Squaliformes. These findings suggest that other members of the Squaliformes, many of which have not previously been examined for parasites, may host additional novel cestode taxa.

Here we describe a new species of RhinebothriumLinton, 1890, from Hypanus guttatus (Bloch and Schneider). Rhinebothrium ramosi n. sp. can be differentiated from all 51 valid species of the genus by having 4-5 testes and uterus that extends throughout the entire length of the proglottid. Only 8 of the above species closely resemble R. ramosi in total length (Rhinebothrium bunburyense, Rhinebothrium chollaense, Rhinebothrium corbatai, Rhinebothrium dasyatidis, Rhinebothrium kruppi, Rhinebothrium lintoni, Rhinebothrium margaritense, and Rhinebothrium reydai). Despite the resemblance, R. bunburyense, R. corbatai, R. dasyatidis, R. lintoni, and R. margaritense can be distinguished from the new species by possessing a larger number of proglottids. The remaining 3 species (R. chollaense, R. kruppi, and R. reydai) overlap in total length and number of proglottids with R. ramosi. However, they can be distinguished from the new species by possessing a single posterior-most bothridial loculus instead of arranged as a pair, as found in the new species. This is the first report of the genus from the coastal waters of Brazil and brings to 52 the number of valid species for this genus. Additionally, we use the patterns of infection and distribution for species of Rhinebothrium to make predictions of expected diversity within the genus, especially for unsurveyed hosts in endemic marine ecoregions of the world.

The endoparasite fauna of Ansell's mole-rat, Fukomys anselli (Burda, Zima, Scharff, Macholan and Kawalika) (Rodentia, Bathyergidae), was studied for the first time near Lusaka, Zambia. We recovered 7 endoparasite taxa including 5 nematodes (Hexametra sp.; Protospirura numidica Seurat, 1914; Protospirura muricola Gedoelst, 1916; Protospirura sp.; and Mammalakis zambiensis Junker, Lutermann and Mutafchiev, 2017); and 2 cestodes (Inermicapsifer sp. and Rodentolepis cf. microstoma Dujardin, 1845) from 272 individuals sampled between February 2009 and February 2010. Species richness (0–2), prevalence (14.7%), and abundance (0.44 ± 0.10) were low, probably as a result of the subterranean lifestyle of the study species. Although effect of host sex on helminth burden was largely absent, helminth burden varied with season and breeding status of the host. This may be a result of seasonal variation in burrow size in response to rainfall, but also the division of labor present in the study species.

Free pre-tetrathyridia of Mesocestoides sp. are described, for the first time, from samples obtained from the coelomic cavity of a ground skink, Scincella lateralis, from Oklahoma. Closer examination of these early-stage tapeworms revealed they were transitional metamorphosis stages between a post-hexacanth procercoid form to the full metacestode of Mesocestoides. A series of transitional stages was found that span the full period of sucker and apical organ development. However, we did not see any fully developed tetrathyridia, i.e., having classic Mesocestoides morphology but with the apical sucker absent following developmental atrophy. This is the first time that metamorphic pre-tetrathyridial stages of a Mesocestoides sp. have been reported in vivo from a natural infection. These observations corroborate earlier reports of such stages of Mesocestoides vogae developed in vitro, though the previously reported isolate of M. vogae is asexually proliferative, and the species from the present study showed no sign of asexual proliferation. The fact that these immediately post-hexacanth stages can occur in a single lizard intermediate host may suggest that Mesocestoides spp. might develop through a simple 2-host life cycle rather than an obligate 3-host cycle that has been speculated to occur by most previous authors. DNA sequence comparisons and phylogenetic analyses based on mitochondrial 12S, cox1, and nad1 genes have demonstrated that our specimens from S. lateralis represent a species clearly distinct from all previously sequenced Mesocestoides and closely related to 2 forms from domestic dogs and Channel Island fox in California previously published as Mesocestoides sp. C.

The lizard Nothobachia ablephara is endemic to dune areas and sandy soils adjacent to the Sao Francisco River in semiarid northeastern Brazil. Forty-nine lizard specimens were collected in 2 Caatinga areas in the municipality of Petrolina in Pernambuco state. Three gastrointestinal helminth taxa were identified, the nematodes Parapharyngodon alvarengai and Physaloptera sp. and the cestode Oochoristica sp. Nothobachia ablephara showed low parasite richness, but high levels of infection by P. alvarengai. There were no significant differences between the parasitism rates of the 2 study areas or between male and female lizards. This is the first study on parasitism in N. ablephara, thereby increasing knowledge of parasite fauna that infect gymnophthalmid lizards in the Sertao of Brazil.

Collections from the dwarf sawfish, Pristis clavata, near Darwin, Australia, in 1997 led to the discovery of the new onchoproteocephalidean genus Matticestus n. gen.-a taxon that has been referred to in molecular phylogenetic analyses in which it has been included as "New genus 8." Its type species, Matticestus anneae n. gen., n. sp., and a second species, Matticestus kathleenae n. sp., are described. Placement of this taxon in the Onchoproteocephalidea is supported morphologically in that both species bear a scolex with 4 bothridia each with a pair of bi-pronged hooks and spinitriches that extend throughout the length of the body. Sequence data for the D1-D3 region of the 28S rDNA gene also place the genus solidly among the other elasmobranch-hosted members of the order. The new genus differs from the other elasmobranch-hosted genera in the order in that its members possess a combination of biloculated bothridia with lateral lappets on the posterior margin of the anterior loculus and a pair of bi-pronged hooks with a distinctive configuration of tubercles and internal channels. Its members are also extremely small. In summary, Matticestus n. gen. is an unusually tiny, "spiny," genus of cestode that seems to exclusively parasitize sawfish of the genus Pristis.

A taxonomic study of monozoic cestodes of the genus Glaridacris Cooper, 1920 (Cestoda: Caryophyllidea), parasites of catostomid fishes in North America, confirmed artificial character of the genus which is split to 2 different, morphologically distinct, and not closely related genera. Glaridacris is newly circumscribed to include only 3 species, Glaridacris catostomi Cooper, 1920 (type species), Glaridacris terebrans ( Linton, 1893 ), and Glaridacris vogei Mackiewicz, 1976 , which are characterized by an elongate body, a cuneiloculate or wedge-shaped scolex with 6 shallow loculi, male and female gonopores at a distance from each other, follicular ovary, and circum-medullary vitelline follicles (lateral and median). A new genus, Pseudoglaridacris n. gen., is proposed to accommodate 3 species characterized by a shorter body, a bothrioloculodiscate scolex with a pair of deeper median bothria and 2 shallower loculi, male and female gonopores close together, non-follicular ovary, and with only lateral vitelline follicles. The species are: Pseudoglaridacris laruei ( Lamont, 1921 ) n. comb. (type species), Pseudoglaridacris confusa (Hunter, 1929) n. comb., and Pseudoglaridacris oligorchis ( Haderlie, 1953 ) n. comb. An annotated list of all species of both genera, with data on their hosts and distribution and keys to their identification, is provided.

Regobothrium microhamulinum n. gen. and n. sp. (Bothriocephalidea: Bothriocephalidae) is proposed to accommodate a new cestode from flatfish Catathyridium jenynsii (Chabanaud, 1922) (Pleuronectiformes: Acharidae; type host) and another 3 freshwater fishes of the orders Characiformes, Cyprinodontiformes, and Siluriformes in the Neotropical Region. The new genus is placed in the Bothriocephalidae because it possesses medioventral uterine and mediodorsal genital pores and a follicular vitellarium. Regobothrium n. gen. is characterized by possessing a tiny, slightly subovate scolex narrower than the strobila, with an apical disc armed with 2 semicircles of 15-17 tiny hooks in each and an acraspedote strobila. Regobothrium n. gen. differs from all bothriocephalid cestodes that have a scolex armed with hooks by their small size (maximum length less than 20 μm) and a triangular shape with the basal part (handle or basal plate) shorter than the distal coniform part (blade). In the other hooked bothriocephalids, hooks have a longer handle than a blade. Regobothrium microhamulinum n. gen. and n. sp. is the third bothriocephalidean cestode described from freshwater teleosts in South America but the first out of Patagonia. Molecular phylogenetics consider Regobothrium as a member of a lineage consisting of (up to now exclusively) freshwater bothriocephalids from the Ethiopian biogeographic region, thus indicating Gondwanan relationship.

The freshwater fish faunas of the Palaearctic and Nearctic regions show similarities but also notable differences, resulting in diverse distributions of their parasites. Relatively few parasite species occur in both regions and fewer still have been examined using molecular data. We report a rare example of 'amphi-Pacific' distribution, involving the common Palaearctic parasite, the caryophyllidean cestode Caryophyllaeides fennica (Schneider, 1902), in the chiselmouth Acrocheilus alutaceus Agassiz and Pickering, 1855, an endemic cyprinid in northwestern Nearctic, Oregon. Available information on nonnative fish species in Oregon suggests that the parasite is native to the area and not introduced. Molecular data (18S ribosomal [r]DNA, 28S rDNA, internal transcribed spacer 2, and cytochrome c oxidase subunit 1 gene) indicate very little genetic divergence between representatives from the Palaearctic and Nearctic, and possibly a relatively more recent colonization of the Nearctic region by this cestode via the Beringian land bridge. This is remarkable considering that Acrocheilus has reportedly been in Oregon since the Miocene.

Raillietina celebensis is a cestode that parasitizes the small intestine of rats and humans. Here, we detail the morphology and morphometry of R. celebensis based on specimens collected from Rattus norvegicus in the municipality of São Gonçalo, state of Rio de Janeiro, Brazil, by light and confocal scanning laser microscopies and also report the results of molecular phylogenetic analyses to determine its relationships within the family Davaineidae. Analysis of the number and size of testes, number and shape of rostellar hooks, cirrus sac length, capsules and eggs per capsule, and morphology of the mature proglottid allowed concluding that the present specimens constitute a new record of R. celebensis in South America. Our genetic and phylogenetic analyses, based on the partial small subunit 18S rRNA gene, revealed R. celebensis to be in the family Davaineidae within the genus Raillietina, in agreement with the morphological taxonomy. Phylogenetic trees obtained by neighbor-joining and maximum likelihood methods demonstrated R. celebensis as a unique taxonomic unit, and also demonstrated some taxonomic inconsistences. The incorporation of Brazilian R. celebensis sequences derived from mammals in the phylogeny of davaineids is consistent with the assertion that neither Raillietina nor Fuhrmannetta can be supported as distinct genera.

Much progress has recently been made in revising the taxonomic assignments of genera originally classified in the polyphyletic "Tetraphyllidea." Many of these genera, including Echeneibothrium, were accommodated in the order Rhinebothriidea. However, beyond this larger taxonomic action, little work has been conducted on this genus over the past 50 yr. Consequently, the criteria used for characterizing species of Echeneibothrium have lagged behind those typically used in more modern descriptions of elasmobranch-hosted cestode taxa. A series of collecting trips to Chile to obtain cestodes from the yellownose skate, Dipturus chilensis , provided a unique opportunity to apply modern morphological and molecular methods to investigate the 3 species of Echeneibothrium reported parasitizing this skate, specifically Echeneibothrium megalosoma, Echeneibothrium multiloculatum, and Echeneibothrium williamsi. In addition to redescribing all 3 species, using morphological data from light and scanning electron microscopy, maximum likelihood and bayesian inference phylogenetic analyses of the D1-D3 regions of the 28S rDNA gene were conducted to assess their relationships among other echeneibothriids for which comparable data are available. Sequencing of 59 specimens representing these 3 species of Echeneibothrium allowed us to assess the intra- and interspecific variation in the 28S rDNA gene. The redescriptions use standardized terminology for scolex morphology, proglottid anatomy, and microthrix forms and pattern; they also expand on the original descriptions to include data on scolex size, ovary size, vas deferens and vaginal configurations, testes arrangement, and genital pore position. Our morphological work led to a major reinterpretation of the scolex morphology with the recognition that all 3 species bear an apical bothridial sucker, rather than an apical loculus, prompting emendation of the diagnosis for the family Echeneibothriidae. The presence of a band of spinitriches at the apex of the apical modification of the scolex proper seems to represent an important feature for distinguishing the 2 portions of the myzorhynchus across species. Intraspecific variation ranged from 0 to 7 bp across species and interspecific variation ranged from a low of 39-46 bp between E. williamsi and E. multiloculatum to a high of 61-66 bp between E. multiloculatum and E. megalosoma. Phylogenetic analyses indicate that the 3 species of Echeneibothrium hosted by the yellownose skate are not each other's closest relatives, suggesting multiple colonization events of D. chilensis have occurred. Further phylogenetic investigation is also likely to confirm the status of the genus Pseudanthobothrium as a synonym of Echeneibothrium because its species generally group among members of Echeneibothrium.

Examination of a small portion of the viscera of an oarfish (Regalecus russellii) recovered from Santa Catalina Island, southern California, revealed numerous tetraphyllidean tapeworm plerocercoids, Clistobothrium cf. montaukensis; 2 juvenile nematodes, Contracaecum sp.; and a fragment of an adult acanthocephalan, family Arhythmacanthidae. This suggests that the fish was relatively heavily parasitized. The presence of larval and juvenile worms suggests that oarfish are preyed upon by deep-swimming predators such as the shortfin mako shark, Isurus oxyrinchus, known to be a definitive host for the adult tapeworm, and also by diving mammals such as sperm whales, Physeter catodon L., hosts of Contracaecum spp. nematodes.

Cichlidocestus n. gen. is proposed to accommodate 2 new species of proteocephalidean cestodes, Cichlidocestus gillesi n. Sp. from Cichlasoma amazonarum in Peru (type species) and Cichlidocestus janikae n. Sp. from Hypsophrys nicaraguensis (all Perciformes: Cichlidae) in Costa Rica. The new genus is unique among all but 1 proteocephalidean genera in the position of the ovary that occupies the middle and posterior thirds of the median region of proglottids (vs. the ovary in the posterior third of proglottids near their posterior margin in all but 1 remaining taxa). In addition, Cichlidocestus is typified by the presence of a voluminous, spherical, internal seminal vesicle, several pairs of ventral excretory canals in the medulla, a pyramidal, quadrilobed scolex with an apical muscular sucker, and the posterior extent of the testes that may reach almost to the posterior margin of proglottids. The new genus shares the position of the ovary and its extension with Sciadocephalus (also a parasite of cichlids in the Neotropics as the new taxon); in all remaining proteocephalideans the ovary occupies the posterior third only. Sciadocephalus differs from Cichlidocestus by a different morphology of the scolex, which possesses an umbrella-like metascolex that is markedly wider than the strobila, the number of ventral osmoregulatory canals, and development of the uterus, which forms capsule-like formations filled with eggs in Sciadocephalus megalodiscus (vs. simple lateral diverticula in Cichlidocestus spp.). Both new species of Cichlidocestus can be easily distinguished from one another by the anterior extent of the poral vitelline follicles (anterior to the cirrus-sac, i.e., preporal, in C. gillesi vs. posterior, i.e., only postporal in C. janikae), size of the eggs (diameter of the external layer of the embryophore of C. gillesi 30-33 μm vs. 44-46 μm in C. janikae), and the number of uterine lateral diverticula (16-21 on 1 side in C. gillesi vs. only 8-12 in C. janikae) and the testes (37-46 in C. gillesi vs. 63-74 in C. janikae). Based on a phylogenetic analysis of the 28S rRNA gene (lsrDNA) sequences, C. gillesi forms a lineage sister to S. megalodiscus, thus supporting the morphological similarity of both genera that occur in fishes of the same family in the same zoogeographical region. Fil: De Chambrier, Alain. Natural History Museum. Department of Invertebrates; Suiza Fil: Pinacho Pinacho, Carlos Daniel. Universidad Nacional Autónoma de México; México. Natural History Museum. Department of Invertebrates; Suiza Fil: Hernández Orts, Jesús Servando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Natural History Museum. Department of Invertebrates; Suiza. Universidad Nacional del Comahue. Instituto de Biología Marina y Pesquera Almirante Storni; Argentina Fil: Scholz, Tomás. Natural History Museum. Department of Invertebrates; Suiza. Biology Centre of the Academy of Sciences of the Czech Republic; República Checa

Four new species are described in the lecanicephalidean genus Hornellobothrium from the ocellated eagle ray, Aetobatus ocellatus, from Australia and Indonesian Borneo. The species possess flat, laterally expanded immature proglottids and a small internal, glandular apical organ diagnostic of the genus. To date, only 2 valid species are recognized in the genus: Hornellobothrium cobraformis ShipleyHornell, 1906 , from " Aetobatus narinari " from Sri Lanka, and Hornellobothrium extensivum Jensen, 2005 , from A. ocellatus , also from Australia. The new species differ from H. cobraformis in the shape of the apical organ and mature proglottids, and from H. extensivum in testes number and scolex dimensions. The new species can be distinguished from one another based on the following combination of features: Hornellobothrium gerdaae n. sp. possesses testes arranged in 2 layers and lacks post-ovarian vitelline follicles; Hornellobothrium iotakotta n. sp. has a single column of 4 testes and lacks spiniform microtriches on the distal bothridial surface; both Hornellobothrium kolossakotta n. sp. and Hornellobothrium najaforme n. sp. possess a single column of 6 testes, but H. najaforme n. sp. is a longer worm with a greater number of laterally expanded immature proglottids. Host associations suggest this genus is potentially limited to A. ocellatus . While reports of up to 9 lecanicephalidean congeners in a single host species exist, they are considered dubious and in need of verification, mainly because of host identification issues. This study demonstrates the presence of at least 5 species of Hornellobothrium in A. ocellatus . Insufficient sampling of this host species across the Indo-Pacific and at each locality may account for the apparent restricted distribution of species of Hornellobothrium.

Floriparicapitus n. gen. (Cestoda: Lecanicephalidea), with Floriparicapitus euzeti n. gen., n. sp. as its type, is erected to house 3 new tapeworm species and 2 known species that are transferred to the new genus, all parasitizing sawfishes and guitarfishes (order Rhinopristiformes) in Indo-Pacific waters. The new genus differs from the 21 valid lecanicephalidean genera in its possession of a large scolex bearing a laterally expanded apical organ in the form of a rugose sheet in combination with a cirrus conspicuously armed with spinitriches and 3 pairs of excretory vessels. It most closely resembles Lecanicephalum, but differs conspicuously in its possession of 3, rather than 1, pair of excretory vessels. Two new species are described from sawfishes: Floriparicapitus euzeti n. sp., from Pristis clavata and Floriparicapitus juliani n. sp. from Pristis pristis, both from Australia. Floriparicapitus plicatilis n. sp. is described from the guitarfish Glaucostegus typus in Australia and the guitarfish Glaucostegus thouin in Malaysian Borneo. Two species formerly assigned to Cephalobothrium are transferred to the new genus; Floriparicapitus variabilis ( Southwell, 1911 ) n. comb. from the sawfish Anoxypristis cuspidata in Sri Lanka and Floriparicapitus rhinobatidis ( Subhapradha, 1955 ) n. comb. from the guitarfish Glaucostegus granulatus in India. The species from guitarfish differ conspicuously from those parasitizing sawfish in their possession of only 4 ( F. plicatilis n. sp.) or 5 (F. rhinobatidis n. comb.) testes per proglottid versus 9 or more in the 3 sawfish-parasitizing species. The latter 3 species differ from one another in scolex width, acetabular size, number of proglottids, and cirrus sac size. As it stands, the new genus appears to be restricted to a subclade of the Rhinopristiformes consisting of the sawfishes and species of Glaucostegus.

In the present paper, species of the Proteocephalus-aggregate de Chambrier, Zehnder, Vaucher, and Mariaux, 2004 (Cestoda: Proteocephalidae) reported from centrarchid and percid fishes in N...

Studies on helminth communities associated with didelphids are scarce; the majority of works have focused at taxonomic level. To increase the ecological knowledge of these host-parasite associations, during March (dry season) of 3 consecutive years (2013-2015) a total of 49 adults of the gray four-eyed opossum (Philander opossum) was collected in the Neotropical portion of Mexico (Agua Fria, Chiapas State) and examined for helminths. The main objectives of this study were to describe the infra- and component communities of helminths associated with P. opossum and to compare the helminth fauna of the Mexican population of this host species with those studied in French Guiana and in other Mexican terrestrial didelphids. The helminthological record of this host consisted of 12 species: 7 taxa of Nematoda, 3 of Trematoda, 1 Cestoda, and 1 Acanthocephala. Eight of the 12 taxa have been previously recorded in Didelphidae and 4 represent accidental infections ( Glossocercus sp., Stomylotrema vicarium, Spirura mexicana and Acanthocephala gen. sp.). Diet of hosts is the main structuring factor of the communities (92% of the helminth species were recruited through ingestion). Forty-eight hosts were parasitized by at least 1 helminth species; Rhopalias coronatus was the most prevalent and abundant species in the hosts sampled. No significant differences were found in global prevalence among the helminth species present in all samplings, considering host sex and year. The dominance exerted by R. coronatus led to low values of evenness and diversity at both community levels. No significant differences were observed in composition of helminth species among the 3 sampling years regarding sex. The results of our study showed changes in helminth abundance at infracommunity level; during the first sampling these changes are explained by species with direct life cycle ( Viannaia sp. and Cruzia tentaculata), whereas in last 2 surveys the explanation can be attributed to species with heteroxenous life cycles (particularly R. coronatus, Duboisiella proloba, and Turgida turgida). Thirty-three percent of the helminth species recorded in P. opossum in Agua Fria is shared with the other 2 terrestrial species of didelphids sampled in different sites of Mexico: Didelphis marsupialis and Didelphis virginiana. In contrast, samples from French Guiana and Agua Fria, differ in terms of helminth fauna, confirming that the helminth communities of opossum species inhabiting the same locality show higher levels of taxonomic similarity than communities of conspecific marsupials allopatrically distributed.

Collection of cestodes from the Taiwan saddled carpetshark, Cirrhoscyllium formosanum, for the first time led to the discovery of Pentaloculum hoi n. sp. This species provided important in...

A new species of the recently erected genus of proteocephalid cestodes, Synbranchiella Arredondo, Alves and Gil de Pertierra, 2017 , is described based on specimens found in the mountain mullet, Dajaus monticola (Bancroft, 1834), from Costa Rica. The new species is placed in Synbranchiella because of the cortical position of the genital organs (typical of the former subfamily Monticelliinae); a robust scolex (lacking a metascolex) having a dome-shaped apex and biloculate suckers (lacking free posterior margins); vitelline follicles in 2 narrow lateral bands; a vagina always anterior to the cirrus-sac; and a genital pore that is markedly pre-equatorial, i.e., close to the anterior margin of proglottids. The new species, Synbranchiella megacirrus, differs from the type and only other species of the genus, Synbranchiella mabelae Arredondo, Alves and Gil de Pertierra, 2017 , that infects the marbled swamp eel, Synbranchus marmoratus Bloch, 1795, in Argentina by the absence of preporal vitelline follicles (present in S. mabelae); a well-developed, large, elongate vaginal sphincter (small and ring-like in S. mabelae); and a large cirrus-sac relative to the proglottid size (cirrus-sac length is on average 48% of the proglottid width in S. megacirrus vs. 31% in the latter species). This is the first adult tapeworm reported from mountain mullet and the first record of the genus outside of South America, thereby greatly extending the range of distribution of species of Synbranchiella.

Staphylocystoides gulyaevi n. sp. is described based on specimens obtained from the dusky shrew Sorex monticolus collected on Sukkwan Island, southeast Alaska. Staphylocystoides gulyaevi n. sp. is compared with other North American members of the genus having 10 rostellar hooks. The new species is morphologically similar to Staphylocystoides parvissima and Staphylocystoides asketus. The uterus in S. gulyaevi n. sp. develops much more rapidly, and a well-developed uterus appears abruptly after it is barely visible in a previous proglottid. In S. parvissima the uterus grows gradually, and its early development is seen in several proglottids. At the level of pre-gravid proglottids the uterus of S. gulyaevi n. sp. occupies only the middle field of the proglottid, while in S. parvissima it fills the whole proglottid including lateral fields. The rostellar hooks in the new species are significantly smaller in size than in S. asketus. Additionally, the new species has fewer proglottids than S. asketus, while having a similar strobila length. Molecular comparison, using 3 genes (28s rDNA, cox1, and nad1), between S. gulyaevi n. sp. and S. parvissima, further corroborates the status of S. gulyaevi n. sp. as a new species. The new species is the seventh species of Staphylocystoides found in North America and the first cestode or any helminth reported from shrews in southeast Alaska.

Two previously unrecognized species of the genus Hymenolepis are described based on specimens obtained from murid rodent species Bullimus luzonicus, Apomys microdon, and Rattus everetti collected on Luzon Island, Philippines. Hymenolepis bicauda n. sp. differs from all known Hymenolepis spp. in relative position of the poral dorsal and ventral osmoregulatory canals, gravid uterus occupying less than half the length of proglottid, relatively few eggs, and the highly characteristic longitudinal split of proglottids at the end of the gravid strobila. Hymenolepis haukisalmii n. sp. differs from all known Hymenolepis spp. in the relative position of both poral and aporal dorsal and ventral osmoregulatory canals and uterus lacking dorsal and ventral diverticula. The shift in the relative position of the dorsal and ventral osmoregulatory canals was not known in Hymenolepis from rodents in other regions of the world and is reminiscent of the situation observed in Hymenolepis erinacei, parasitic in hedgehogs, and members of the genus Talpolepis, parasitic in moles. The cosmopolitan species Hymenolepis diminuta was the only member of the genus previously reported from the Philippines. The genus Hymenolepis Weinland, 1858, includes hymenolep- idid cestodes with an unarmed scolex and rudimentary rostellar apparatus, parasitic primarily in rodents, with a few species known from bats and 1 from hedgehogs. Members of the genus have been reported from the Palearctic, Nearctic, Ethiopian, and Oriental regions (Lopez-Neyra, 1942a, 1942b; Skrjabin and Matevosyan, 1948; Spassky, 1954; Yamaguti, 1959; Hunkeler, 1972; Ryzhikov et al., 1978; Genov, 1984; Gardner, 1985; Schmidt, 1986; Gardner and Schmidt, 1988; Czaplinski and Vaucher, 1994; Mas-Coma and Tenora, 1997; Sawada, 1997; Gulyaev and Melnikova, 2005; Makarikova et al., 2010; Makarikov and Tkach, 2013). To the best of our knowledge, Hymenolepis diminuta (Rudolphi, 1819) is the only species of Hymenolepis previously reported from the Philippines (Tubangui, 1931; Fedorko, 1999). As part of a biodiversity survey of terrestrial vertebrates and their parasites in the Philippines, we found hymenolepidid cestodes belonging to Hymenolepis in three species of murid rodents, namely, the large Luzon forest rat Bullimus luzonicus (Thomas, 1895), the small Luzon forest mouse Apomys microdon Hollister, 1913, and the Philippine forest rat Rattus everetti (G ¨ unther, 1879), collected in Aurora Province, Luzon Island. These 2 species of cestodes, described herein, are morphologically distinct from previously known Hymenolepis species.

The proteocephalidean cestode Harriscolex nathaliae n. sp. (Proteocephalidae: Zygobothriinae) is described from the intestine of the spotted sorubim Pseudoplatystoma corruscans (Spix and Agassiz) (Siluriformes: Pimelodidae) from the Parana River basin in Argentina. This new species differs from the only species of the genus, Harriscolex kaparari (Woodland, 1935), which is a parasite of Pseudoplatystoma tigrinum (Linnaeus) from the Amazon River in Brazil, by its larger scolex (width of 450–750 μm vs. 305–340 μm), the position of the vagina in relation to the cirrus sac (anterior and posterior vs. only anterior), an asymmetrical vaginal sphincter, the arrangement of vitelline follicles (1 narrow longitudinal band on each side of the proglottid vs. 2 pairs of wide longitudinal bands on dorsal and ventral sides), and a higher number of uterine diverticula (22–45 vs. 16–20). Harriscolex nathaliae is covered with 2 types of microtriches, acicular filitriches and gladiate spinitriches.

Unexplained and episodic die-offs of the dwarf surf clam, Mulinia lateralis , have been reported on the West Atlantic coast, with such an occurrence in South Carolina in June 2010. A sample of live clams from the 2010 South Carolina event was collected, and 200 clams were measured and necropsied. Two species of tapeworm larvae were observed. Plerocercoids (Duplicibothrium sp.) occupied the digestive gland ducts, and merocercoids (Rhodobothrium sp.) were found beneath the mantle. Specimens of both species were sequenced to obtain partial 28S rRNA gene sequences, and they were identified as the tetraphyllidean D. minutum and the rhinebothriidean R. paucitesticulare, based on an NCBI Standard Nucleotide BLAST search. Of the 200 clams, 2.1% were infected with merocercoids (mean intensity 1.3 ± 0.2) and 75% with plerocercoids (mean intensity 4.3 ± 3.7). Intensity of infection by plerocercoids increased significantly with individual shell length. The presence of plerocercoids was associated with enlargement of the digestive gland ducts, but no other pathology was observed. Because uninfected clams were abundant among the stranded molluscs, these parasites are not considered to be the causative agent of the die-off. This is a new host record for both elasmobranch tapeworms.

A new species of Grillotia was found from teleosts and elasmobranchs along the Patagonian shelf off Argentina. Grillotia patagonica n. sp. is described from plerocerci recovered from gadiform (Moridae) and perciform fish (Cheilodactylidae, Bovichtidae, and Nototheniidae) and adults from the smallthorn sand skate Psammobatis rudis (Rajiformes, Rajidae). Grillotia patagonica most closely resembles species in the Grillotia erinaceus species complex (viz., Grillotia borealis, Grillotia brayi, Grillotia dollfusi, G. erinaceus, and Grillotia musculara) in having 4 hooks per principal row and 2 or more intercalary rows in the metabasal region, a band of hooks on the external surface of the tentacle, numerous proglottids, a hermaphroditic sac, internal and external seminal vesicles, uterine pore, and attachment of the retractor muscle in the mid region of the tentacular bulb. Grillotia patagonica n. sp. is unique among all valid species in the genus by having the hooks on the first row reduced and of a different shape from the rest of the metabasal rows. Despite the diversity of elasmobranchs that are available as definitive hosts for species in Grillotia, most species (10/14) are oioxenous or mesostenoxenous. The specificity for the last intermediate host is variable among species of Grillotia, with most plerocerci being oioxenous (5/15) or euryxenous (8/15). Host specificity is higher for the adult stage in the definitive host (mean HS(S) = 4.07) than for the plerocerci (mean HS(S) = 7.30). All the species with oioxenous specificity (either larvae or adults) have limited geographic distributions. Some previous records of species of Grillotia from fishes caught off Argentina require reconsideration, i.e., G. erinaceus, Grillotia minuta (reported as Grillotia bothridiopunctata) and G. borealis . An updated host-parasite checklist for the valid species of Grillotia is also presented along with new host records for Grillotia carvajalregorum.

Yorkeria chonburiensis n. sp. (Tetraphyllidea: Onchobothriidae) is described from the spiral intestine of a specimen of the brownbanded bamboo shark, Chiloscyllium punctatum, collected from the Gulf of Thailand, Chon Buri Province, Thailand. Yorkeria chonburiensis n. sp. is distinguished from all other species of Yorkeria by the pattern of proglottids (craspedote as opposed to acraspedote) and the proglottid number (more than 168). The new species is larger than all other members of Yorkeria, and the medial hooks are slightly larger than the lateral hooks with a ratio of 1:1.87–1:1.96. The position of the genital pore is 29–34% from the anterior margin of proglottid, greater than all other members of Yorkeria.

The bear tapeworm Diphyllobothrium ursi is described based upon the morphology of adult tapeworms recovered from the brown bear (Ursus arctos middendorffi) and larval plerocercoids found in sockeye salmon (Oncorhynchus nerka) from Kodiak Island in Alaska in 1952. However, in 1987 D. ursi was synonymized with Diphyllobothrium dendriticum, and the taxonomic relationship between both species has not subsequently been revised. In this study mitochondrial cytochrome c oxidase subunit 1 gene (cox1) sequences of holotype and paratype D. ursi specimens that had been preserved in a formalin-acetic acid-alcohol solution since the time the species was initially described approximately 60 yr ago were analyzed. Molecular and phylogenetic analysis of the cox1 sequences revealed that D. ursi is more closely related to D. dendriticum than it is to Diphyllobothrium nihonkaiense and Diphyllobothrium latum. In addition to molecular evidence, differences in the life cycle and ecology of the larval plerocercoids between D. ursi and D. dendriticum also suggest that D. ursi is a distinct species, separate from D. dendriticum and D. nihonkaiense, and also possibly from D. latum .

Atriotaenia sanmarci n. sp. (Cestoda: Anoplocephalidae) is described as a parasite of the Andean hog-nosed skunk, Conepatus chinga (Carnivora: Mephitidae), from Cusco, Perú. The new species is primarily distinguished from related species by the distribution, and greater number, of testes, i.e., 194-223 versus 40-60 in Atriotaenia sandgroundi (Sandground, 1926) Baer, 1935, 47-73 in Atriotaenia procyonis (Chandler, 1942) Spasskii, 1951, and 21-84 in Atriotaenia incisa Railliet, 1899. Also, there are differences with respect to the larger dimensions of suckers (300-371 µm vs. 140 in A. sandgroundi, 83-134 in A. procyonis, 70-140 in A. incisa, and 155-192 in Atriotaenia hastati Vaucher, 1982) and in the cirrus pouch length (204-732 µm vs. 90 in A. sandgroundi, 200-220 in A. procyonis, 100-180 in A. incisa, and 150-205 in A. hastati). The new species differs from A. sandgroundi and A. hastati in having a larger body size (122-133 mm vs. 10.6 and 10, respectively). This cestode is the fifth species of Atriotaenia Sandground, 1926.

Specimens originally identified as Arostrilepis horrida from the Nearctic are revised, contributing to the recognition of a complex of cryptic species distributed across the Holarctic region. Previously unrecognized species are described based on specimens in cricetid (Neotominae) and geomyid rodents. Arostrilepis mariettavogeae n. sp. in Peromyscus californicus from Monterey County, California and Arostrilepis schilleri n. sp. in Thomomys bulbivorus from Corvallis, Oregon are characterized. Consistent with recent studies defining diversity in the genus, form, size, and spination (pattern, shape, and size) of the cirrus are diagnostic; species are further distinguished by the relative position and length of the cirrus sac and arrangement of the testes. Species of Arostrilepis have not previously been described in rodents outside of the Arvicolinae or from localities in the Nearctic. These studies emphasize the need for routine deposition of archival specimens and information, from survey, ecological, and biogeographic studies, in museum collections to serve as self-correcting records for biodiversity at local, regional, and continental scales.

The cestode fauna of the shortfin devilray, Mobula kuhlii (MüllerHenle, 1841) was examined for the first time. The work resulted in the discovery of a new genus and species of rhinebothriidean tapeworm. Crassuseptum pietrafacei, n. gen. n. sp. is erected here on the basis of its unique scolex and proglottid morphology. Histological sections and examination by light and scanning electron microscopy demonstrated that this new genus differs from all other rhinebothriidean genera in its possession of bothridia in which the proximal and distal sides are confluent, i.e., not separated by a rim of tissue, and in its possession of testes that extend to the posterior margin of the ovary. This new species is characterized in part by its possession of stalked, elongate bothridia lacking lateral constrictions, with 13-15 prominent transverse bothridial septa and 4 reduced transverse septa, craspedote proglottids, each with 2-3 layers of testes in cross section, and a vas deferens that joins the cirrus sac at its anterior margin. Histological and optical sections through bothridial septa revealed that the transverse septa are formed by septal muscles separate from bothridial radial musculature, extending from the anterior side to the posterior side of each septum. This is only the second species rhinebothriidean cestode reported from mobulids. This study adds to the number of new species and genera of elasmobranch cestodes discovered off of the island of Borneo.

International audience; The mature spermatozoon of Bothriocotyle sp. is filiform and tapered at both extremities. It possesses 2 axonemes of unequal length, showing the 9 + "1" pattern of Trepaxonemata. The anterior extremity exhibits a crest-like body. Thereafter, the crest-like body disappears, and the first axoneme is surrounded by a ring of cortical microtubules (about 27 units) that persist until the appearance of the second axoneme. This ring of cortical microtubules is characteristic only for species of Bothriocephalidea and represents a very useful phylogenetic character. The spermatozoon cytoplasm is slightly electron-dense and contains numerous electron-dense granules of glycogen in several regions. The anterior and posterior extremities of the spermatozoon lack cortical microtubules. The posterior extremity of the spermatozoon of Bothriocotyle sp. possesses a nucleus and a disorganized axoneme, which also characterizes spermatozoa of the Echinophallidae studied to date.

A new proteocephalidean cestode is described from spot pangasius, Pangasius larnaudii (Siluriformes: Pangasiidae), from Tonle Sap Lake in Cambodia and a new genus, Pangasiocestus , is proposed to accommodate it. The genus is placed in the Gangesiinae because its scolex possesses a large rostellum-like apical organ and its genital organs (testes, ovary, vitellarium, and uterus) are situated in the medulla, with some vitelline follicles paramuscular. Pangasiocestus romani n. gen. and n. sp., the type and only species of the new genus, is characterized mainly by its rosette-like scolex composed of 4 lobes bearing a small sucker in their center, and the apical part with a large, discoidal, rostellum-like apical organ devoid of hooks, by weakly developed inner longitudinal musculature formed by very few isolated muscle fibers, uneven size of testes in immature and mature proglottids, with lateral testes smaller and more dense than median ones, by very narrow lateral bands of vitelline follicles, formed usually by single follicles, and by the vagina anterior to the cirrus sac. This is the first proteocephalidean cestode from a pangasiid catfish identified to the species level (proteocephalidean cestodes from 3 Pangasius spp. reported in an unpublished account from Vietnam, misidentified as Proteocephalus osculatus (Goeze, 1782) [ = Glanitaenia osculata ], are not considered).

Three new species of diphyllidean cestodes are described from rhinobatid elasmobranchs of the genus Glaucostegus from the Indian and Pacific Oceans. All 3 new species have 11 apical hooks (6 type-A and 5 type-B hooks) and, therefore, differ in this feature from all but 5 of the 39 valid species of Echinobothrium. In addition, Echinobothrium tetabuanense n. sp. from Glaucostegus cf. typus in the Sulu Sea, Borneo differs from all of its congeners in the number and arrangement of hooklets, number of spines on the cephalic peduncle, and the number and distribution of testes. Echinobothrium sematanense n. sp. from Glaucostegus thouin in the South China Sea, Borneo, can be distinguished from its congeners based on the following combination of characters, i.e., small size (worms less than 1 mm long), number of hooklets, spines per column on the cephalic peduncle, and number of testes. Echinobothrium weipaense n. sp. from northern Australia is unique in the position of the cirrus sac and genital pore, both structures being well posterior and not overlapping the ovary. An emended description of the microthrix pattern on the scolex of Echinobothrium chisholmae from G. typus in Australia is also presented.

New lecanicephalidean cestodes inhabiting the spiral intestine were investigated in 4 of the 6 known species of eagle rays of the genus Aetomylaeus Garman. Hosts examined consisted of 5 specimens of Aetomylaeus vespertilio from northern Australia, 5 of Aetomylaeus maculatus from Borneo, 10 of Aetomylaeus nichofii sensu stricto from Borneo, and 7 of Aetomylaeus cf. nichofii 2 from northern Australia. As a result of these new collections, 3 new genera and 6 new species of lecanicephalideans are formally described. Aetomylaeus vespertilio hosted the new genera and species Collicocephalus baggioi n. gen., n. sp. and Rexapex nanus n. gen., n. sp., as well as Aberrapex weipaensis n. sp. Aetomylaeus maculatus and A. nichofii sensu stricto hosted 3 new species of the novel genus Elicilacunosus , with the former eagle ray hosting Elicilacunosus sarawakensis n. sp. and the latter hosting both Elicilacunosus dharmadii n. sp. and Elicilacunosus fahmii n. sp. No new lecanicephalideans were described from A. cf. nichofii 2. Collicocephalus n. gen. is conspicuously unique among the genera of its order in possessing a large, retractable apical organ that, in cross-section, is transversely oblong, rather than round. Rexapex n. gen. is distinctive in its possession of an apical organ that bears 18 papilliform projections around its perimeter, and Elicilacunosus n. gen. is unlike any other known lecanicephalidean, or eucestode, in its possession of a region of musculo-glandular tissue along the midline of the dorsal and ventral surfaces of its proglottids, manifested externally as a tandem series of depressions. Among other features, A. weipaensis n. sp. differs from its congeners in its lack of post-ovarian vitelline follicles. All 6 new species were each restricted to a single species of Aetomylaeus . These records formally establish species of Aetomylaeus as hosts of lecanicephalideans. A summary of cestodes of myliobatid rays is presented.

A larval marine cestode was found in 82.0% of 834 Pacific hake (Merluccius productus) stomachs collected from 341 trawl stations along the United States west coast during the summers of 2008 and 2009. Morphology and DNA sequencing was used to identify the cestode as Nybelinia surmenicola. In an examination of 131 Pacific hake stomachs collected from the same region in 1999, N. surmenicola prevalence was 35.1%. The results from a general linear model suggested that their prevalence is influenced by year and latitude, Pacific hake size, and sex. Mean intensity of N. surmenicola in 2008-2009 was 20.22 (±1.13 SE) and was positively related to Pacific hake length and the latitude of collection. Year-1 Pacific hake (27 cm length) had significantly lower prevalence and intensity of N. surmenicola compared to older and larger fish. Pacific hake collected south of Point Conception, California (32.5 to 35°N) had lower prevalence and intensity of N. surmenicola compared to those collected in northern latitudes (35.1 to 48.4°N). Higher N. surmenicola prevalence in Pacific hake in recent years suggests food-web fluctuations in the northern California current ecosystem caused by changes in ocean transport of zooplankton or pelagic fish distributions and warrants future monitoring as a metric for ecosystem change.

The parasite fauna of many Australian rodents is poorly known. The ectoparasite and helminth faunas of Pseudomys delicatulus, Pseudomys desertor, Pseudomys gracilicaudatus, and Pseudomys hermannsburgensis were determined and compared. In total, 12 species of arthropods, 2 cestodes, and 13 nematodes were found. Species richness of parasites was highest in P. hermannsburgensis and lowest in P. desertor. Despite the sampling effort, the number of parasite species discovered did not reach an asymptote for any of the host species, indicating that the full parasite fauna was not examined. Helminth species richness was highest in the insectivorous P. hermannsburgensis and lower in the obligate herbivores. The structure of parasite component communities was influenced by the social structure of the host species, not surprisingly, with the most highly social species having the highest richness of parasites. Habitat preferences also provided contrast between the helminth component communities, with heligmonellid nematodes occurring in damp woodlands and dominating the parasite fauna of P. gracilicaudatus. Oxyurid nematodes dominated the component communities of the 3 other species, all of which inhabit drier habitats.

The proteocephalidean tapeworm, Corallobothrium solidum, type species of the genus, is redescribed on the basis of the examination of its type specimens and extensive material recently collected from Malapterurus electricus (type host). Some morphological characteristics of taxonomic importance are reported for the first time, such as the presence of semispherical (U-shaped) sphincters on the external (outer) margin of the suckers, a vaginal sphincter, a well-developed seminal receptacle, and a unique morphology of the eggs. Corallobothrium solidum differs from the 2 remaining species of the genus, both parasitic in channel catfishes (Ictaluridae), in its scolex shape, morphology of its suckers, presence of longitudinal and transverse grooves on the body surface, dense network of excretory canals in the apical part of the scolex, morphology of the eggs, and uterine development. The non-monophyletic nature of Corallobothrium is further supported by molecular data (partial sequences of the 28S rRNA gene) because C. solidum and the 2 remaining species from ictalurids do not form a monophyletic assemblage. Therefore, Essexiella n. gen. is proposed to accommodate Essexiella fimbriatum new comb. (type and only species; syn. Corallobothrium fimbriatum) from channel catfish. Essexiella n. gen. differs from Corallobothrium, Megathylacoides, and Megathylacus by the absence of a sphincter in the suckers, from Corallotaenia by the shape of the scolex and the number and shape of proglottids, and from Paraproteocephalus by the structure of the uterus. The diagnosis of Corallobothrium, which becomes monotypic and restricted to electric catfishes in Africa, is emended. The remaining species of Corallobothrium, Corallobothrium parafimbriatum, is tentatively transferred to Corallotaenia as Corallotaenia parafimbriata n. comb., based on molecular data, small size of the strobila, and shape of the scolex.

This study was undertaken to identify the community composition, structure, and dynamics of helminths infecting the gastrointestinal tract (GIT) of lake whitefish (Coregonus clupeaformis) collected from 4 sites in northern lakes Huron (Cheboygan and De Tour Village) and Michigan (Big Bay de Noc and Naubinway) from fall 2003 through summer 2006. A total of 21,203 helminths was retrieved from the GITs of 1,284 lake whitefish. Approximately 42% (SE = 1.4%) of the examined lake whitefish were infected with at least 1 helminth species in their GIT, with a mean intensity of 39.4 worms/fish (SE = 0.3) and a mean abundance of 16.4 worms/fish (SE = 0.1). Collected helminths appeared to be generalists and consisted of 2 phyla (Acanthocephala and Cestoda) and 5 species (Acanthocephalus dirus, Neoechinorhynchus tumidus, Echinorhynchus salmonis, Cyathocephalus truncatus, and Bothriocephalus sp.). Lake whitefish from Lake Huron on average had greater infection prevalences, abundances, and intensities than did fish from Lake Michigan. Infection parameters for each of the helminth species generally followed the same pattern observed for the combined data. Acanthocephalus dirus was the most prevalent and abundant helminth in lake whitefish GITs, although intensity of infection was the greatest for C. truncatus. Helminth infection parameters often peaked in the spring while diversity was greatest in the winter samples. There was substantial temporal variability in helminth infections with prevalences, abundances, and intensities often fluctuating widely on consecutive sampling occasions. Analysis of the GIT helminth community composition suggested that 3 (Big Bay de Noc, De Tour Village, and Cheboygan) of the 4 primary spawning sites, overall, had similar community compositions. The reason for the observed spatial and temporal variability in the lake whitefish GIT helminth infections remains to be elucidated. The findings of this study represent the most comprehensive parasitological study ever conducted on lake whitefish in the Great Lakes and will provide valuable information for future comparisons.

The stinging catfish Heteropneustes fossilis (Bloch) (Siluriformes: Heteropneustidae) has been reported to harbor as many as 19 species of caryophyllidean tapeworms (Cestoda) of 11 genera in tropical Asia (Indomalayan zoogeographical region). However, a critical review of the species composition has shown that only 1 species, Lucknowia fossilisi Gupta, 1961 (Lytocestidae), is a specific parasite of H. fossilis. Three other species, Djombangia penetrans Bovien, 1926 (syn., Djombangia caballeroi Sahay and Sahay, 1977 ), Pseudocaryophyllaeus ritai Gupta and Singh, 1983 (syn. Pseudocaryophyllaeus lucknowensis Gupta and Sinha, 1984 ), and Pseudocaryophyllaeus tenuicollis (Bovien, 1926) Ash, Scholz, Oros and Kar, 2011 (syn. P. mackiewiczi Gupta and Parmar, 1982 ), were found only once. Lucknowia fossilisi is redescribed on the basis of new material collected in West Bengal and voucher specimens from Maharashtra, India. A total of 9 species of Capingentoides, Lucknowia, Lytocestus, Pseudoadenoscolex, Pseudocaryophyllaeus, Pseudoheteroinverta, and Sukhapatae are newly synonymized with L. fossilisi and previous synonymies of 9 other species, proposed by Hafeezulah (1993), are confirmed. Generic diagnosis of Lucknowia Gupta, 1961 is amended. In addition, 1 species of Pseudobatrachus and 2 species of the monotypic genera Pseudoneckinverta and Sudhaena are invalidated as nomina nuda.

Larval tapeworms (Polypocephalus sp.) reside within the central nervous system of decapod crustaceans. Living within the nervous system would seem to create an excellent opportunity for the parasites to manipulate the behavior of their hosts, so we tested the hypothesis that behavior of white shrimp ( Litopenaeus setiferus ) would be correlated with the level of parasitic infection. We videorecorded the behavior of L. setiferus for 8 hr, then examined the nervous system and digestive glands for parasite infection. Larval Polypocephalus sp. were found in the nerve cord, often in large numbers, but only very rarely in the digestive gland, which was typically infected by the larval stage of the nematode, Hysterothylacium sp. There were significantly more Polypocephalus larvae in the abdominal and thoracic ganglia than the subesophageal ganglia and brain. Walking, but not swimming, was significantly and positively related to the number of Polypocephalus sp. lodged in nervous tissue, as well as shrimp carapace length. Polypocephalus sp. is 1 of only a few parasites residing inside the host nervous system and it may, therefore, be suitable for investigating mechanisms of parasite manipulation of invertebrate host behavior.

The diphyllobothriidean cestode Schistocephalus solidus typically infects threespine sticklebacks that are too small to allow the parasite to reach a mature size. As a result, the parasite must allow further growth of its host to reach the size at which it becomes competent to infect and reproduce in the definitive host. At times, however, intensity of infection can be high, leading to crowding among parasites and to heavy burdens causing mortality among hosts. Our data show that, during a previously observed epizootic, large percentages of plerocercoids (average 75% per host, 82% among all parasites pooled) did not grow to become massive enough in 1-yr-old threespine sticklebacks to be capable of establishment and maturation in the definitive host. Massive deaths of 1-yr- old sticklebacks due to infection during the epizootic resulted in the great misfortune of a disaster for a large number of parasites, resulting in dramatically reduced transmission of S. solidus.

The great white shark Carcharodon carcharias Linnaeus, 1758 is a versatile and fierce predator (and responsible for many shark attacks on humans). This apex predator feeds on a wide range of organisms including teleosts, other elasmobranchs, cephalopods, pinnipeds, and cetaceans. Although much is known about its diet, no trophic links have been empirically identified as being involved in the transmission of its tapeworm parasites. Recently, the use of molecular tools combined with phylogenetics has proven useful to identify larval and immature stages of marine tapeworms; utilization of the technique has been increasing rapidly. However, the usefulness of this approach remains limited by the availability of molecular data. Here, I employed gene sequence data from the D2 region of the large subunit of ribosomal DNA to link adults of the tapeworm Clistobothrium carcharodoni Dailey and Vogelbein, 1990 (Cestoda: Tetraphyllidea) to larvae for which sequence data for this gene are available. The sequences from the adult tapeworms were genetically identical (0% sequence divergence) to those available on GenBank for "SP" 'small' Scolex pleuronectis recovered from the striped dolphin (Stenella coeruleoalba) and Risso's dolphin (Grampus griseus). This study is the first to provide empirical evidence linking the trophic interaction between great white sharks and cetaceans as a definitive route for the successful transmission of a tetraphyllidean tapeworm. Using the intensity of infection data from this shark and from cetaceans as proxies for the extent of predation, I estimate that this individual shark would have consumed between 9 to 83 G. griseus , fresh, dead, or both, in its lifetime.

The endoparasite fauna of the spiny mouse (Acomys spinosissimus) was studied for the first time from April 2007 until April 2009 in a population from the Limpopo Province of South Africa. In a total of 129 mice examined, only 6 endoparasite taxa were found, 2 nematode species (Syphacia minuta, Monanema joopi), 1 genus of cestodes ( Rodentolepis spp.), and unidentified hymenolepidid fragments. In addition, 1 pentastomid species (Armillifer grandis) as well as unidentified porocephalid specimens were recovered. The overall prevalence was low, at 15.5%, and only 1 individual harbored more than 1 parasite species. With 12.4% prevalence, S. minuta was the most prevalent parasite. Its prevalence and abundance were significantly higher during the dry and cooler season than during the wet and warm season, while a female-biased burden was observed during the wet season only. For the remaining parasite species, low prevalence prevented meaningful statistical analyses. The observed parasite species richness, prevalence, and abundance for A. spinosissimus were low compared to values reported for other Acomys spp. This may be linked to the lack of anthropogenic influences in the study population as well as the small size of A. spinosissimus .

New collections of cestodes from the spiral intestines of the lanternsharks Etmopterus spinax and Etmopterus pusillus off the island of Faial, in the Azores, Atlantic Ocean, have yielded 2 new species of trypanorhynchs belonging to Aporhynchus. Both species share the distinctive lack of all elements of the rhyncheal system that are characteristic of this genus. The identity of Aporhynchus norvegicus is clarified to allow it to be distinguished from A. menezesi n. sp., which also parasitizes E. spinax. This new species differs conspicuously from its congeners in that its mature and gravid proglottids are wider than long, rather than longer than wide, and also in its lack of spinitriches on the scolex. Aporhynchus pickeringae n. sp., the new species from E. pusillus , differs from all of its congeners except A. norvegicus in that it is a relatively delicate worm with relatively fewer testes. It also possesses fewer proglottids and a wider pedunculus scolecis than does A. norvegicus. Sections through the scolex of A. menezesi n. sp. support use of the term bothriate, rather than difossate, in reference to the scolex configuration of some trypanorhynchs. A key to the 4 species of Aporhynchus is provided.

Cellular details of early embryogenesis have been studied extensively among cyclophyllidean cestodes, but have been reported for only 2 species of the order Proteocephalidea, both belonging to the genus Proteocephalus. Thus, we performed a detailed ultrastructural analysis of early embryos of a second species, Corallobothrium fimbriatum, including early events in the formation of the embryonic envelopes. Adult worms were collected from the small intestine of brown bullhead catfish, Ameiurus nebulosus, from the St. Lawrence River in North America and processed by standard methods for transmission electron microscopy. The vitelline capsule consists of 2 closely apposed electron-dense membranous layers, separated by a more electron-lucent material. The 2 vitellocytes that accompany each oocyte contain numerous ribosomes, vesicles, and lipid droplets. These fuse to form a vitelline syncytium, which elongates and almost completely encircles the cleaving embryo by the 4-blastomere stage, forming a partial lipid-rich cellular envelope that undergoes apoptosis as cleavage continues. This envelope is later replaced by outer and inner embryonic envelopes. The outer envelope derives from the fusion of the vitelline syncytium with the cytoplasm of macromeres, whereas the inner envelope originates from 3 mesomeres. Simultaneous to the formation of the embryonic envelopes, other blastomeres multiply and differentiate, while some micromeres undergo degeneration or apoptosis. In most respects, ultrastructural features of early C. fimbriatum embryos closely resemble those of previously studied Proteocephalus longicollis, but differ somewhat from those of other orders. This demonstrates that, despite marked ultrastructural heterogeneity within some orders such as the Cyclophyllidea, some embryonic traits distinguish cestode orders from each other.

We studied patterns of variation in cestode communities of 3 abundant rodent species that live in sympatry in the Niayes of the Retba Lake, Western Senegal. We evaluated whether the host species have the same parasites and, within host species, whether the variability in parasite community is related to intrinsic (sex, age of the host individual) or extrinsic (habitat, season) factors. Arvicanthis niloticus was parasitized by 2 cestode species, namely Inermicapsifer madagascariensis and the highly dominant Raillietina trapezoïdes . Raillietina baeri was the only cestode species found in Mastomys erythroleucus , and there was no cestode in M. huberti . Prevalence and abundance levels of cestodes were very high in A. niloticus , especially in adults. Seasonal and habitat effects were found in both cestode communities of M. erythroleucus and A. niloticus . Local host specificity and abundance/prevalence levels suggested variations in the interaction between rodents and cestode intermediate host species among habitats and seasons.

These are the first paleoparasitological results from the Late Holocene in Patagonian coprolites. Coprolites collected from layers dated at 3,480 and 2,740 yr before present (B.P.), from the archaeological site Cerro Casa de Piedra, were examined. The site is a hill located in a forest steppe ecotone in Perito Moreno National Park. The coprolites could belong to humans or to other carnivores such as canids. After rehydration and spontaneous sedimentation of the samples, the parasite contents were examined. Results obtained showed the common presence of eggs of a Calodium sp., eggs of other capillariids and trichostrongylids, oocysts of Eimeria macusaniensis (Apicomplexa), and eggs of taeniids (Cestoda). Although the generic identification of some parasites could not be provided, the presence of tapeworm eggs represents the first record for the Late Holocene in Patagonia and shows that parasitism by cestodes existed in the region in pre-Columbian times. Results indicate that in the Late Patagonic Holocene, zoonotic helminths may have been commonly present in the inhabitants of Patagonia. The parasites found in the coprolites allow us to deduce what these people were eating and, thus, indicate what other pathogens, such as viruses, bacteria, and parasitic protozoans, may have infected them via the same sources.

Anoplocephalid cestodes have a worldwide distribution, but relatively few species are known from South American rodents. By examining the collections of the Harold W. Manter Laboratory of Parasitology and the United States National Parasite Collection, 6 new species of Monoecocestus Beddard, 1914, are described, along with a redescription of Monoecocestus mackiewiczi Schmidt and Martin, 1978, based on the type specimens. The discussion includes commentary about uterine development, an important taxonomic character of the family, the vaginal dilation in immature segments (a character of potential taxonomic importance), and the implication of host usage to the evolutionary history and biogeography of species in this genus.

Host specificity evidently is not expressed by various species of Diphyllobothrium that occur typically in marine mammals, and people become infected occasionally when dietary customs favor ingestion of plerocercoids. This report mainly concerns 2 species, Diphyllobothrium pacificum and Diphyllobothrium arctocephalinum, for which sea lions (Otariidae) are final hosts. The taxonomic status of those cestodes has not been clearly discernible because of misinterpretation of relationships; complex synonymies have resulted from misidentification(s). Stiles and Hassall in 1899 obtained, but did not describe, cestodes from the northern fur seal (Otariidae; Pribilof Islands). That taxon was subsequently studied by several investigators, with diverse conclusions. The valid designation is D. pacificum (Nybelin, 1931). In 1937, Johnston and Drummond described separately 2 conspecific cestodes from sea lions near Australia, designated D. arctocephalinum and Diphyllobothrium arctocephali. Both names have been listed incorrectly as synonyms of D. pacificum.