Two new species of Scyphophyllidium (Cestoda: Phyllobothriidea) from Chaenogaleus macrostoma (Bleeker) (Elasmobranchii: Carcharhiniformes) from the Persian Gulf, Iran

Two new species of Scyphophyllidium Woodland, 1927 are described from the Hooktooth shark, Chaenogaleus macrostoma (Bleeker), from the Persian Gulf, Iran. Scyphophyllidium hormuziense n. sp. is assigned to morphological category 2 of its genus because it possesses bothridial marginal loculi and an apical sucker on each flat bothridium, and lacks bothridial facial loculi. Within category 2, it is distinguished from its congeners, except for S. janineae (Ruhnke, Healy and Shapero, 2006), by possessing, rather than lacking, a prominent cephalic peduncle. It differs from S. janineae in the distribution of the vitelline follicles. Scyphophyllidium iraniense n. sp. is assigned to morphological category 5 because its bothridia are essentially flat and lack proximal apertures, marginal loculi, facial loci and semi-circular muscle bands, and bears weakly serrate gladiate spinitriches on its distal bothridial surfaces. Within its morphological category, the presence of a long cephalic peduncle distinguishes S. iraniense n. sp. from its congeners lacking this structure or possessing a short cephalic peduncle. It further differs from S. arnoldi (Ruhnke and Thompson, 2006) and S. typicum (Subhapradha, 1955) in total length, from S. paulum (Linton, 1897) in lacking a conspicuous band of muscles along the locular periphery of the bothridia, and from S. kirstenae (Ruhnke, Healy and Shapero, 2006) in the distribution of the vitelline follicles. This study brings the number of the valid Scyphophyllidium species of the Persian Gulf to five.

Cestodes of Pseudobatos horkelii (Mller and Henle) (Rhinopristiformes) including Rhinebothrium quequense n. sp. (Rhinebothriidea) and Caulobothrium pieroi n. sp. (Tetraphyllidea) from the southwestern Atlantic

Two new species of cestodes were described from the Brazilian guitarfish, Pseudobatos horkelii (Mller and Henle) (Rhinopristiformes: Rhinobatidae), from coastal waters off Argentina in the southwestern Atlantic Ocean. Rhinebothrium quequense n. sp. (Rhinebothriidea) differs from its congeners by a combination of morphological characters, including the total number of loculi, the absence of loculi at the level of bothridial constriction, the number of testes per proglottid, and the number of proglottids per worm. Caulobothrium pieroi n. sp. (Tetraphyllidea) can be distinguished from the other members of the genus by the following set of morphological features including the presence of stalked bothridia with apical sucker, the number of loculi per bothridium, the number of testes per proglottid, and the number of proglottids per worm. The discovery of R. quequense n. sp. and C. pieroi n. sp. in the Brazilian guitarfish not only increases the number of rhinebothriideans and tetraphyllideans in the southwestern Atlantic, but also expands the elasmobranchs list to include P. horkelii for the first time as a new host record for cestodes globally. In addition, this is not only the first report of a species of Rhinebothrium in rhinobatids in the region, but it is also the first Caulobothrium species infecting a rhinopristiform batoid.

Endoparasites of Adelophryne maranguapensis Hoogmoed, Borges & Cascon, 1994 (Anura, Eleutherodactylidae), an endemic and threatened species from an altitude swamp in northeastern Brazil

Adelophryne maranguapensis is an endangered anuran species endemic to the Maranguape residual mountain, Ceará State, northeaster Brazil, which is under strong anthropogenic pressure. There are still few studies on the natural history of this species that allow a better understanding of its biology and can provide the basis for conservation actions. Studies on endoparasitism are an important source for the comprehension of ecological relationships, as well as for providing information on host biology and its relevance to ecosystems. Thus, we present information about the endoparasites helminths, the relationship of parasite abundance with the size of individuals and the parasite difference between the sexes in A. maranguapensis, to elucidate some characteristics in the host-parasite relationship and the use of the area of this anuran. We analysed 107 specimens deposited in the Herpetological Collection of the Federal University of Ceará, sampled from 2010 to 2012. Total prevalence of 24.30% was recorded, and four parasitic taxa were identified, Aplectana sp., Physaloptera sp., Parapharyngodon sp. and an unidentified Ascarid. No relationship between the abundance of parasites and snout-vent length was found and the parasite difference between the sexes. Even though identification of the parasites at species level was not possible, A. maranguapensis follows a common pattern in parasitism of Neotropical species.

Host relationships and geographic distribution of species of Acanthobothrium Blanchard, 1848 (Onchoproteocephalidea, Onchobothriidae) in elasmobranchs: a metadata analysis

Species of Acanthobothrium have been documented as parasites of the spiral intestine of elasmobranchs. Results of a metadata analysis indicate that 114 species of elasmobranchs have been reported as hosts of 200 species of Acanthobothrium. The metadata analysis revealed that 3.7% of species of sharks and 14.9% of species of rays that have been reported as hosts to date; some species are parasitized by more than one species of Acanthobothrium. This work provides a Category designation, as proposed by Ghoshroy and Caira (2001), for each species of Acanthobothrium. These Category designations are a tool to facilitate comparisons among members of Acanthobothrium for descriptions of new species in the future.

Insights from new cestodes of the crocodile shark, Pseudocarcharias kamoharai (Lamniformes: Pseudocarchariidae), prompt expansion of Scyphyophyllidum and formal synonymization of seven phyllobothriidean genera - at last!

Three new cestode species are described from the crocodile shark (Pseudocarcharias kamoharai) in Ecuador. All three were examined with light and scanning electron microscopy. The unique combination of morphological features in one of the new species prompted formal investigation of the non-monophyly of Paraorygmatobothrium relative to the morphologically similar genera Doliobothrium, Guidus, Marsupiobothrium, Nandocestus, Orectolobicestus, Ruhnkecestus and Scyphophyllidium. Sequence data generated for part of the 28S rDNA gene were subjected to maximum likelihood (ML) analysis. The resulting tree led to the synonymization of six of these seven genera with Scyphophyllidium, and transfer of their species to the latter genus. With the new species, the number of described members of Scyphophyllidium is now 45. The diagnosis of Scyphophyllidium is revised to accommodate these species. In addition, to expedite future descriptions, eight categories of Scyphophyllidium species are circumscribed, based largely on bothridial features. Scyphophyllidium timvickiorum n. sp. is a category 1 species. Beyond being the smallest category 1 species, it bears, rather than lacks, apical suckers and lacks, rather than bears, strobilar scutes. The two other new species are members of Clistobothrium. Clistobothrium amyae n. sp. differs from its congeners in bothridial shape, elongate cephalic peduncle and tiny size. Clistobothrium gabywalterorum n. sp. differs from the two of its congeners that also possess foliose bothridia in overall size and testis number. Despite their substantial morphological differences, the ML tree indicates they are sister taxa. Both are unique among their congeners in possessing cephalic peduncle spinitriches. The diagnosis of Clistobothrium is revised accordingly.

Two new species of Acanthobothrium Blanchard, 1848 (Onchobothriidae) in Narcineentemedor Jordan & Starks, 1895 (Narcinidae) from Acapulco, Guerrero, Mexico

Two species of Acanthobothrium (Onchoproteocephalidea: Onchobothriidae) are described from the spiral intestine of Narcineentemedor Jordan & Starks, 1895, in Bahía de Acapulco, Acapulco, Guerrero, Mexico. Based on the four criteria used for the identification of species of Acanthobothrium, A.soniae sp. nov. is a Category 2 species (less than 15 mm in total length with less than 50 proglottids, less than 80 testes, and with the ovary asymmetrical in shape). Acanthobothriumvidali sp. nov. is a Category 6 species (more than 15 mm in total length with more than 50 proglottids, fewer than 80 testes, and the ovary is asymmetrical). The new species differ from similar species from the Pacific Ocean by total length, the number of proglottids, diameter of the accessory sucker, the length of the cirrus sac, the number of testes per proglottid and the measurements of hooks. With the recognition of A.soniae sp. nov. and A.vidali sp. nov., 42 species of Acanthobothrium have been reported from the Pacific coast of the Americas. This is the first report of species of Acanthobothrium from a member of Narcine from Mexico and it brings the number of species reported from elasmobranchs from the Pacific Coast of Mexico to 13.

Systematics and diversification of Anindobothrium Marques, Brooks & Lasso, 2001 (Eucestoda: Rhinebothriidea)

Tapeworms of the genus Anindobothrium Marques, Brooks & Lasso, 2001 are found in both marine and Neotropical freshwater stingrays of the family Potamotrygonidae. The patterns of host association within the genus support the most recent hypothesis about the history of diversification of potamotrygonids, which suggests that the ancestor of freshwater lineages of the Potamotrygonidae colonized South American river systems through marine incursion events. Despite the relevance of the genus Anindobothrium to understand the history of colonization and diversification of potamotrygonids, no additional efforts were done to better investigate the phylogenetic relationship of this taxon with other lineages of cestodes since its erection. This study is a result of recent collecting efforts to sample members of the genus in marine and freshwater potamotrygonids that enabled the most extensive documentation of the fauna of Anindobothrium parasitizing species of Styracura de Carvalho, Loboda & da Silva, Potamotrygon schroederi Fernández-Yépez, P. orbignyi (Castelnau) and P. yepezi Castex & Castello from six different countries, representing the eastern Pacific Ocean, Caribbean Sea, and river basins in South America (Rio Negro, Orinoco, and Maracaibo). The newly collected material provided additional specimens for morphological studies and molecular samples for subsequent phylogenetic analyses that allowed us to address the phylogenetic position of Anindobothrium and provide molecular and morphological evidence to recognize two additional species for the genus. The taxonomic actions that followed our analyses included the proposition of a new family, Anindobothriidae fam. n., to accommodate the genus Anindobothrium in the order Rhinebothriidea Healy, Caira, Jensen, Webster & Littlewood, 2009 and the description of two new species-one from the eastern Pacific Ocean, A. carrioni sp. n., and the other from the Caribbean Sea, A. inexpectatum sp. n. In addition, we also present a redescription of the type species of the genus, A. anacolum (Brooks, 1977) Marques, Brooks & Lasso, 2001, and of A. lisae Marques, Brooks & Lasso, 2001. Finally, we discuss the paleogeographical events mostly linked with the diversification of the genus and the protocols adopted to uncover cryptic diversity in Anindobothrium.

Annotated checklist of fish cestodes from South America

An exhaustive literature search supplemented by a critical examination of records made it possible to present an annotated checklist of tapeworms (Cestoda) that, as adults or larvae (metacestodes), parasitize freshwater, brackish water and marine fishes, i.e. cartilaginous and bony fishes, in South America. The current knowledge of their species diversity, host associations and geographical distribution is reviewed. Taxonomic problems are discussed based on a critical evaluation of the literature and information on DNA sequences of individual taxa is provided to facilitate future taxonomic and phylogenetic studies. As expected, the current knowledge is quite uneven regarding the number of taxa and host-associations reported from the principal river basins and marine ecoregions. These differences may not only reflect the actual cestode richness but may also be due to the research effort that has been devoted to unravelling the diversity of these endoparasitic helminths in individual countries. A total of 297 valid species, 61 taxa identified to the generic level, in addition to unidentified cestodes, were recorded from 401 species of fish hosts. Among the recognized cestode orders, 13 have been recorded in South America, with the Onchoproteocephalidea displaying the highest species richness, representing c. 50% of all species diversity. The majority of records include teleost fish hosts (79%) that harbour larval and adult stages of cestodes, whereas stingrays (Myliobatiformes) exhibit the highest proportion of records (39%) among the elasmobranch hosts. Fish cestodes are ubiquitous in South America, being mostly recorded from the Warm Temperate Southeastern Pacific (WTSP; 31%) for marine hosts and the Amazon River basin (45%) for freshwater ones. The following problems were detected during the compilation of literary data: (i) unreliability of many records; (ii) poor taxonomic resolution, i.e. identification made only to the genus or even family level; (iii) doubtful host identification; and (iv) the absence of voucher specimens that would enable us to verify identification. It is thus strongly recommended to always deposit representative specimens in any type of studies, including faunal surveys and ecological studies. An analysis of the proportion of three basic types of studies, i.e. surveys, taxonomic and ecological papers, has shown a considerable increase of ecological studies over the last decade.

Diversification and species boundaries of Rhinebothrium (Cestoda; Rhinebothriidea) in South American freshwater stingrays (Batoidea; Potamotrygonidae)

BACKGROUND

Neotropical freshwater stingrays (Batoidea: Potamotrygonidae) host a diverse parasite fauna, including cestodes. Both cestodes and their stingray hosts are marine-derived, but the taxonomy of this host/parasite system is poorly understood.

METHODOLOGY

Morphological and molecular (Cytochrome oxidase I) data were used to investigate diversity in freshwater lineages of the cestode genus Rhinebothrium Linton, 1890. Results were based on a phylogenetic hypothesis for 74 COI sequences and morphological analysis of over 400 specimens. Cestodes studied were obtained from 888 individual potamotrygonids, representing 14 recognized and 18 potentially undescribed species from most river systems of South America.

RESULTS

Morphological species boundaries were based mainly on microthrix characters observed with scanning electron microscopy, and were supported by COI data. Four species were recognized, including two redescribed (Rhinebothrium copianullum and R. paratrygoni), and two newly described (R. brooksi n. sp. and R. fulbrighti n. sp.). Rhinebothrium paranaensis Menoret & Ivanov, 2009 is considered a junior synonym of R. paratrygoni because the morphological features of the two species overlap substantially. The diagnosis of Rhinebothrium Linton, 1890 is emended to accommodate the presence of marginal longitudinal septa observed in R. copianullum and R. brooksi n. sp. Patterns of host specificity and distribution ranged from use of few host species in few river basins, to use of as many as eight host species in multiple river basins.

SIGNIFICANCE

The level of intra-specific morphological variation observed in features such as total length and number of proglottids is unparalleled among other elasmobranch cestodes. This is attributed to the large representation of host and biogeographical samples. It is unclear whether the intra-specific morphological variation observed is unique to this freshwater system. Nonetheless, caution is urged when using morphological discontinuities to delimit elasmobranch cestode species because the amount of variation encountered is highly dependent on sample size and/or biogeographical representation.

Brevimulticaecum sp. (Nematoda: Heterocheilidae) larvae parasitic in freshwater fish in the Pantanal wetland, Brazil

During the study of metazoan parasites of freshwater fish in the Pantanal wetland (state of Mato Grosso do Sul, Brazil), third-stage larvae of Brevimulticaecum sp. were collected from the abdominal cavity, liver parenchyma, mesentery, skeletal muscles and stomach wall of the following species: Gymnotus inaequilabiatus, Hemisorubim platyrhynchos, Hoplias aff. malabaricus, Myleus levis, Pseudoplatystoma corruscans, Pygocentrus nattereri, Serrasalmus marginatus and Sorubim lima. The larvae exhibited the main characteristics of the genus Brevimulticaecum, such as short ventricular appendices and the position of excretory pore and excretory nucleus. This is the first report and description of larval specimens of Brevimulticaecum parasitic in these hosts, which are fish species distributed throughout South America.