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A new species of Bacciger Nicoll, 1914, is described from the digestive tract of the American gizzard shad, Dorosoma cepedianum (Lesueur), in some inland waterways of Mississippi, and in Mobile Bay, Alabama, U.S.A. This now represents the only nominal species in the genus from the northwest Atlantic Ocean or inland tributaries of eastern North America north of Mexico. Two potentially close relatives that range in the northwest Atlantic Ocean are Baccigeroides ovatus (Price, 1934) Cutmore, Bray and Cribb, 2018, and Pseudobacciger manteriNahhas and Cable, 1964. The new species differs from Bo. ovatus mainly by having the genital pore opening immediately anteriad from the ventral sucker rather than far anteriad from it at the pharynx level, and from P. manteri mainly by having a distinct cirrus sac rather than having the terminal genitalia free in the parenchyma. The 3 genera are currently classified in the Faustulidae Poche, 1926. Although life cycles are unknown for the American species, evidence from life history of the related species Bacciger bacciger (Rudolphi, 1819) Nicoll, 1914, and Pseudobacciger harengulae (Yamaguti, 1938) Nahhas and Cable, 1964, combined with molecular phylogenetic evidence, indicate that the studied digeneans likely have a nonoculate trichocercous cercaria. We discovered sporocysts containing nonoculate trichocercous cercariae we identified as Cercaria rangiaeWardle, 1983, infecting the viscera of the Gulf wedge clam, Rangia cuneata (G. B. Sowerby I), in the Pascagoula River, Mississippi, U.S.A. We generated the internal transcribed spacer 2 (ITS2) region and a portion of the 28S rDNA gene from the new species and C. rangiae. Dissimilarity at both sequences demonstrated that the stages were not conspecific. Bayesian inference analyses applied separately to the ITS2 region, and the partial 28S rDNA gene, resulted in trees with similar topology, both depicting the new species and C. rangiae as sister taxa. The possible identity of C. rangiae and the phylogenetic relationships among species of Bacciger and related genera are discussed. We consider Bacciger lesteriBray, 1982, and Bacciger sprentiBray, 1982, incertae sedis in the Microphalloidea Ward, 1901. All other species of Bacciger, and species belonging in PseudobaccigerNahhas and Cable, 1964, and Baccigeroides Dutta, 1995, are transferred from the Faustulidae to the Gymnophalloidea Odhner, 1905, where their familial affinities remain incertae sedis. [ABSTRACT FROM AUTHOR]

Hypostomus commersoni is a freshwater fish, native to the Paraná River basin, which plays an important role in trophic networks of this system. This study aimed at analyzing the structure of the endohelminth community of H. commersoni from two shallow lagoons in the municipality of Santa Fe, Argentina. In the 51 hosts analyzed, 2103 helminths were found. Hosts from Belgrano Park lagoon were infested with Genarchella genarchella, Saccocoelioides nanii, Raphidascaris (Sprentascaris) sp., and Gorytocephalus elongorchi. Hosts from the Western Urban Nature Reserve lagoon were infested with Thometrema magnifica, Procamallanus (Procamallanus) annipetterae, Raphidascaris (Sprentascaris) sp., Gorytocephalus elongorchi, and Proteocephalidae spp. In both host populations, the prevalence of some parasites was high, and species richness and diversity of component communities were low. The distribution pattern of helminth was aggregated in all cases. No correlation was found between the length of the host and the richness and abundance of endoparasites. The total number of parasites and the specific richness per host in both lagoons did not differ significantly. The findings on G. genarchella, P. (P.) annipetterae, G. elongorchi, and Proteocephalidae spp. were the first records in his host. [ABSTRACT FROM AUTHOR]

Two cases of human philophthalmosis have been reported in Japan. Gravid flukes removed from the eyes of the patients were broken, but their morphological characteristics suggest that an unknown species of the genus Philophthalmus is involved as a pathogen for humans. The mitochondrial DNA barcode of the human eye fluke enabled us to discover its larval stage from the Japanese mud snail, Batillaria attramentaria. The discovered cercaria had previously been temporarily described as "Philophthalmid sp. I." In this study, we examined the infection status of B. attramentaria with Philophthalmid sp. I found on a muddy seashore of the Seto Inland Sea, Japan, and the resulting metacercariae were experimentally administered to Japanese quails to develop them into the gravid adult stage. The complete specimens of the adult and larval stages allowed us to describe a new species. Based on morphological and molecular analyses, Philophthalmus hechingeri n. sp. is proposed for the human-infecting eye fluke in Japan. The natural definitive hosts of the new species are unknown. However, the habitat of B. attramentaria suggests that shorebirds (seagulls, sandpipers, and plovers) might be the possible candidates. [ABSTRACT FROM AUTHOR]

A new species of the candiru genus Paracanthopoma is described from the floodplains of the Bananal Island, a transition area between the Cerrado and Amazon, in the Araguaia River basin, central Brazil. Paracanthopoma cangussu sp. nov. is distinguished from its congeners, Paracanthopoma parva and Paracanthopoma saci, by the presence of seven opercular odontodes, five dentary teeth, five median premaxillary teeth, and first dorsal‐fin pterygiophore in a vertical through the centrum of the 23th or 24th vertebra. It is further distinguished from each congener by an exclusive combination of character states, comprising the number of vertebrae, number of precaudal vertebrae, number of dorsal procurrent caudal‐fin rays, number of ventral procurrent caudal‐fin rays, number of dorsal‐fin rays, disposition of pores on the cephalic portion of the latero‐sensory system, absence of an anterior process on the anterior margin of parieto‐supraoccipital, number of dorsal‐fin pteryigiophores and number of interopercular odontodes. Although vandelliines are known for being exclusively hematophagous, with guts gorged with blood, two cleared and stained specimens of P. cangussu sp. nov. had Chironomidae larvae (Insecta) on their guts. Because most specimens of P. cangussu sp. nov. were collected with stomachs filled with blood, it was hypothesized that the species feeds accidentally or occasionally on insects. [ABSTRACT FROM AUTHOR]

[Display omitted] • The rate of recognition of new marine trematode families, genera and species is reducing. • Molecular approaches have dramatically improved the delineation of species. • Molecular phylogenetics have stabilised the higher classification of marine trematode. • Life cycle information for marine trematode families lags that of terrestrial and freshwater taxa. • The next 50 years could see an approach to a complete inventory of marine trematodes. Trematodes are the richest class of platyhelminths in the marine environment, infecting all classes of marine vertebrates as sexual adults and many phyla of marine invertebrates as part of their life cycles. Despite the cryptic nature of their existence (almost all marine trematodes are internal parasites), they have been the focus of study for almost 250 years, with the first species described in 1774. Here we review progress in the study of the "biodiversity" of these parasites, contrasting the progress made in the last 50 years (post-1971) to that in the almost 200 years before it (pre-1972). We consider an understanding of biodiversity to require knowledge of the species present in the system, an understanding of their evolutionary relationships (which informs higher classification), and, specifically for trematodes, an understanding of their complex life cycles. The fauna is now large, comprising well over 5,000 species. Although species description continues, we see evidence of a slow-down in all aspects of discovery. There has been only one completely new family identified since 1984 and the proposal of new genera is in decline as is the description of new species, especially for those of tetrapods. However, the extent to which this slow-down reflects an approach to the richness asymptote is made uncertain by changes in the field; reduced effort and difficulty of study may be important components of the effect. Regardless of how close we are to a complete description of the fauna, we infer that the outline is well-understood although the details are not. Adoption of molecular methodologies over the last 40 years have complemented morphometric analyses to facilitate objective recognition of species; however, despite these objective data, there is still inconsistency between authors on species delimitation. Molecular methodologies have also completely revolutionised inference of relationships at all levels, from within genera to between orders, and underpinned elucidation of novel life cycles. We expect the next 50 years to produce further dividends from technological innovations. The backdrop to the field will be global environmental concerns and the growing problem of funding for basic biodiversity studies. [ABSTRACT FROM AUTHOR]

The digenetic trematode family Gorgocephalidae comprises just a few species, and the literature devoted to the lineage consists of only a handful of reports. With one exception, all reports have been based on material collected in the Indo-West Pacific, an expansive marine ecoregion stretching from the east coast of Africa to Easter Island, Hawaii and French Polynesia. We collected adult and intramolluscan gorgocephalids from kyphosid fishes and littorinid gastropods from several Australian localities, and from South Africa and French Polynesia. Specimens of Gorgocephalus kyphosi and G. yaaji were collected from, or near, their type-localities, providing new morphological and molecular (COI , ITS2 and 28S) data needed for a revised understanding of species boundaries in the family. Two new species are recognized: Gorgocephalus euryaleae sp. nov. and Gorgocephalus graboides sp. nov. New definitive host records are provided for described species and three new intermediate hosts are identified. These new records are all associated with Kyphosus fishes and littorinid gastropods, reaffirming the restriction of gorgocephalids to these hosts. Most significantly, we provide evidence that G. yaaji is distributed from South Africa to French Polynesia, spanning the breadth of the Indo-West Pacific. Our findings have significant relevance regarding digenean species delineation over geographic range. [ABSTRACT FROM AUTHOR]

Thirty dolphin fish Coryphaena hippurus Linnaeus, 1758 (Perciformes: Coryphaenidae) were collected from the Gwadar Coast, Balochistan. Four hosts were found positive with trematodes of genus Tetrochetus Looss, 1912. Present specimen differs from its congeners in having a smaller body, muscular and robust body; both the oral sucker and ventral suckers have same size, oral sucker terminal; testes oval-shaped, pre-ovarian and laterally positioned in middle of the body; median, oval-shaped ovary located near hind testis; vitelline glands tubular, compact, extending from anterior border of ovary up to mid-level of ventral sucker. On the basis of these varying characters between present species and its congeners, a new species Tetrochetus balochistanensis proposed. However, this genus is the first host recorded from Balochistan, Pakistan. [ABSTRACT FROM AUTHOR]

This study was conducted to determine seasonal infections of the metazoan parasite fauna of Mesopotamian spiny eel (Mastacembelus mastacembelus) inhabiting in Euphrates and Tigris Basin, Eastern Anatolia, Turkey. A total of 122 fish were caught between November 2016 and August 2017 and 4932 parasites were recorded. One species of protozoan parasite (Ichthyophthirius multifiliis), two species of Monogenea (Mastacembelocleidus heteranchorus and Diplozoon sp.), one species of Digenea (Diplostomum spathaceum), one species of Cestoda (Polyonchobothrium magnum), two species of Nematoda (Procamallanus viviparous and Rhabdochona denudata), two species of Copepoda (Eergasilus sieboldi and Argulus foliaceus), one species of Hridunea (Piscicola geometra) and one species of Unionidae (Unio pictorum) observed respectively. According to their prevalence, I. multifiliis (10.66%), M. heteranchorus (58.19%), Diplozoon sp. (0.1%), D. spathaceum (63.93%), P. magnum (24.59%), P. viviparous, (0.41%), R. denudata (9.01%), E. sieboldi (14.75%), A. foliaceus (3.27%), P. geometra (3.3%) and U. pictorum (58.19%) were found. All parasite species except A. foliaceus in this study are new records. From these parasites, Diplozoon sp. and P. geometra are the first records for the Mesopotamian spiny eel parasite fauna worldwide. [ABSTRACT FROM AUTHOR]

Purpose: Cardiocephaloides comprises strigeid trematodes that represent a small genus. In this study, metacercaria identified as Cardiocephaloides sp. was collected from the Gangetic leaffish Nandus nandus from the Ganga River at Bairaj, Bijnor (29º01'N, 77º45'E) in the state of Uttar Pradesh (U.P.), India. Partial DNA sequences of the internal transcribed spacers (ITS1-5.8S-ITS2) and 28S gene of nuclear ribosomal DNA were generated and compared with available sequences of Cardiocephaloides species from Genbank database. Methods: Encysted metacercariae of Cardiocephaloides sp. were collected from Nandus nandus were processed, identified and documented using morphological methods. The ITS1-5.8S-ITS2 cluster and 28S gene of ribosomal DNA of metacercariae were also sequenced and used for phylogenetic analysis. Results: The infections of brain parasites are poorly understood in India and if studies are available, they are not properly described. During this study, the species collected were found belongs to the genus Cardiocephaloides. Metacercariae of Cardiocephaloides sp. is distinguished morphologically from others that also harbor brain by the presence of having an egg shape cyst and body elongate oval in shape with well-developed anterior part. The metacercariae are identified by matching of molecular sequence data and is compared to other species of Strigeidae. Conclusion: This is the first record of metacercaria of Cardiocephaloides sp. from India. This molecular data from the present study will provide future comparative insights into species of Cardiocephaloides and its close affiliation to other congeners from different geographical areas. [ABSTRACT FROM AUTHOR]

Introduction: The cercariae of avian blood flukes Trichobilharzia szidati (Digenea, Schistosomatidae) are known to cause cercarial allergic dermatitis ("swimmer's itch") in humans. Global epidemics can have significant impacts on local tourism-related economies in recreational areas. Little is known about the genetic polymorphism of the parasite population, or about the variability of the non-coding regions of mitochondrial DNA (mtDNA) and the possibility of using this as a genetic marker. Materials and Methods: The T. szidati cercariae were collected over 7 years from 33 naturally infected Lymnaea stagnalis snails from five sites at two neighboring lakes in Belarus. We investigated the variability of the short (SNR) and long (LNR) non-coding regions of mt DNA and the genetic diversity within the 1125-bp sequences of the gene for subunit 1 of cytochrome c oxidase (cox1). Results: In the SNR sequences, we found only length variability caused by changes in the number of bases in the mononucleotide tracts T6–T8. LNR demonstrates high variability in nucleotide sequence length (182–260 bp) depending on the presence of two long deletions of 59 and 78 nucleotides. Both mitochondrial loci (LNR and cox1) are characterized by high haplotype diversity (H = 0.922 and H = 1.0, respectively); the nucleotide diversity is significantly higher for LNR (π = 1.926 ± 0.443) compared to cox1 (π = 0.704 ± 0.059). Phylogenetic reconstructions based on the variability of each of the loci (LNR and cox1) and their concatenated sequences revealed their shallow structure and the absence of a correlation between the distribution of single-nucleotide polymorphisms and the geographic origin of parasites from two Belarusian lakes. We identified at last four weakly sublineages in the phylogenetic pattern of T. szidati. The carriers of each deletion have specific patterns for each of the two loci and form their own phylogeographic sublineages. An association between two fixed LNR substitutions and a fixed non-synonymous substitution in cox1 was found in four representatives of one lineage that had a short deletion in the LNR. Conclusions: This study clarified the phylogeographic structure of the Belarusian population of T. szidati. Our data provide the basis for the use two mt markers in large-scale population studies of the parasite, as well as for studying the molecular evolution of coding and non-coding mtDNA in trematodes. [ABSTRACT FROM AUTHOR]

Abstract Background Parasitic flatworms (Trematoda: Digenea) represent one of the most remarkable examples of drastic morphological diversity among the stages within a life cycle. Which genes are responsible for extreme differences in anatomy, physiology, behavior, and ecology among the stages? Here we report a comparative transcriptomic analysis of parthenogenetic and amphimictic generations in two evolutionary informative species of Digenea belonging to the family Psilostomatidae. Methods In this study the transcriptomes of rediae, cercariae and adult worm stages of Psilotrema simillimum and Sphaeridiotrema pseudoglobulus, were sequenced and analyzed. High-quality transcriptomes were generated, and the reference sets of protein-coding genes were used for differential expression analysis in order to identify stage-specific genes. Comparative analysis of gene sets, their expression dynamics and Gene Ontology enrichment analysis were performed for three life stages within each species and between the two species. Results Reference transcriptomes for P. simillimum and S. pseudoglobulus include 21,433 and 46,424 sequences, respectively. Among 14,051 orthologous groups (OGs), 1354 are common and specific for two analyzed psilostomatid species, whereas 13 and 43 OGs were unique for P. simillimum and S. pseudoglobulus, respectively. In contrast to P. simillimum, where more than 60% of analyzed genes were active in the redia, cercaria and adult worm stages, in S. pseudoglobulus less than 40% of genes had such a ubiquitous expression pattern. In general, 7805 (36.41%) and 30,622 (65.96%) of genes were preferentially expressed in one of the analyzed stages of P. simillimum and S. pseudoglobulus, respectively. In both species 12 clusters of co-expressed genes were identified, and more than a half of the genes belonging to the reference sets were included into these clusters. Functional specialization of the life cycle stages was clearly supported by Gene Ontology enrichment analysis. Conclusions During the life cycles of the two species studied, most of the genes change their expression levels considerably, consequently the molecular signature of a stage is not only a unique set of expressed genes, but also the specific levels of their expression. Our results indicate unexpectedly high level of plasticity in gene regulation between closely related species. Transcriptomes of P. simillimum and S. pseudoglobulus provide high quality reference resource for future evolutionary studies and comparative analyses.

The developments in the study of digeneans of deep-sea fish in the 21st Century are documented and discussed. Most recent work has been on the bathyal fauna (i.e. 1,000m-2,999 m depth), with virtually nothing on the abyssal fauna (i.e. deeper than 3,000 m). The one study on hydrothermal vent digeneans has indicated that these regions probably harbour a distinctive fauna. The demarcation of the deep-sea fauna is blurred at the poles, where the cold-adapted fauna appears similar to the shallower bathyal fauna. The abyssal fauna, however, appears distinct, possibly due to adaptations to variable or ultra-high pressures. The digenean fauna of bathypelagic fishes is depauperate. Recent phylogenetic studies reinforce the view that the typical deep-sea fauna has radiated in the deep-sea. Encroachment into the deep from shallow water is relatively rare. Overall, the digenean fauna in the deep-sea is distinctly less diverse that the equivalent fauna in shallow waters. A major conclusion is that our understanding of the deep-sea digenean fauna is poor, and that much further work over a much wider area is needed.

Abstract Background Parasites may mediate the success of biological invasions through their effect on host fitness and thus, on host population growth and stability. However, a release from the pressure of parasites is strongly related to the genetic differentiation of the host. In invasive host populations, the number of available genetic variants, allowing them to ‘fight’ the infection, are likely to be influenced by founder events and genetic drift. The level standing genetic variation of invasive populations may be crucial in successfully adapting to new environments and resisting diseases. We studied invasive populations of raccoon that experienced a random reduction in genetic diversity during the establishment and evaluated the relationship between host immune genetic diversity and intestinal parasites infection. Results We distinguished two different genetic clusters that are characterized by different sets of functionally relevant MHC-DRB alleles. Both clusters were characterized by considerably different allele-parasite associations and different levels of parasite infection. The specific resistance MHC-DRB alleles explained the lower prevalence of Digenea parasites. An increased infection intensity was related to the presence of two MHC-DRB alleles. One of these alleles significantly decreased in frequency over time, causing a decrease of Digenea abundance in raccoons in consecutive years. Conclusions Our findings suggest that intestinal parasites can exert selective pressure on an invasive host with lowered levels of immune genetic diversity and contribute to promoting local adaptation over time. The random genetic drift that created the two different genetic clusters in the invasive raccoon range imposed completely different MHC-parasite associations, strongly associated with the infection status of populations. Our findings underline the role of standing genetic variation in shaping host-parasite relationships and provide empirical support that functional genetic variation may be, at least partly, responsible for differences in the success of invasive populations.

Seven species of Didymozoidae were found parasitizing three species of scombrid fishes along the Rio de Janeiro coast, southwestern Atlantic Ocean. All these species are reported here for the first time in Brazil and new hosts are presented, which adds to the knowledge of these species. The main morphological and morphometric features of each species are presented. A new combination of two species allocated to Lobatocystis Yamaguti, 1965 is proposed here, based on the previously established synonymy of Lobatocystis and Lobatozoum Ishii, 1935.

Background: Allocreadiids are relatively small digeneans that appear to be restricted to freshwater systems distributed across the world. Allocreadiids are highly diverse in the Americas, particularly in the Neotropical biogeographical region. Their taxonomic history has been rather controversial, with several taxonomic reassessments and the description of new genera and species., Methods: We sampled Creptotrematina specimens from a characid collected in the Pardo River, Paranapanema River basin in Brazil, and specimens of C. aguirrepequenoi, from Astyanax spp. in several localities between northern Mexico and Costa Rica. The specimens were studied through integrative approaches using morphological and molecular analyses of the 28S rDNA gene and two different regions of the COI mtDNA gene., Results: We describe a new species of Creptotrematina which is differentiated from other congeners by the overall body size, but in particular by the size and position of the cirrus-sac, distribution of the vitelline follicles, and extension of uterine loops in the posterior end of body. Phylogenetic analyses of the 28S rDNA and COI mtDNA genes placed the new species in a monophyletic clade together with all other sequenced species of Creptotrematina, and as a sister species of C. batalhensis. Genetic divergences between the new species and other Creptotrematina spp. varied from 1.1 to 1.2% for the 28S rDNA and 12.4-14.3% for the COI mtDNA. Phylogenetic analysis based on COI mtDNA showed the isolates of C. aguirrepequenoi grouped in four monophyletic clades representing populations geographically separated along a wide geographical range spanning between northern Mexico and Costa Rica, with an estimated genetic divergence between 3.9% and 8.9%., Conclusions: Our findings based on integrative analyses recognize Creptotrematina saltograndensis n. sp. from a characid collected in the Pardo River, Paranapanema River basin in Brazil and provide validation of the wide geographical distribution of C. aguirrepequenoi across Middle-America parasitizing Astyanax spp.; the genetic divergence of the species through the analysis of two regions of COI mtDNA points towards considering it represent a species complex, although we refrain at the moment on describing a new species, awaiting for further verification using other molecular markers, and obtaining fresh material for a more detailed taxonomic analyses. This study increases the known diversity of allocreadiids and contributes to the understanding of evolutionary relationships, host-parasite relationships, and biogeographic history of the group., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Rastrelliger brachysoma (Bleeker, 1851), the short mackerel, is a dietary staple and of significant economic demand in Southeast Asia and Thailand. However, the demand for short mackerel has precipitated an overfishing crisis, leading to a depletion of fish stocks. Overfishing, coupled with parasitism, may result in a decline in the population of R. brachysoma. Digenetic trematode infection is prevalent in marine fish and has a considerable impact on the overall health of the fish. Here, to identify digenetic trematodes infecting R. brachysoma, we aim to determine the identity, prevalence, and intensity of digenean infections in R. brachysoma from the Gulf of Thailand. A total of 194 short mackerel were obtained from Chon Buri Province, where digeneans were isolated and identified. The molecular identity of the digeneans was confirmed using the nuclear 28S rRNA gene. Of the 194 short mackerel, 100% were found to be infected with digeneans, comprising of Lecithocladium, Prodistomum, Opechona, and Aphanurus. Lecithocladium was the most prevalent (98%) and had the highest intensity of infection (37 mean intensity), followed by Prodistomum (75% prevalence and 17 mean intensity). Our study thus presents the first evidence of digeneans infecting the economically important short mackerel from the Gulf of Thailand. The high infection rate of digenetic trematodes may have implications on the health of R. brachysoma, further driving their population decline. These data underscore the importance of safeguarding fisheries resources in the Gulf of Thailand, and downstream conservation efforts are crucial for evidence-based management decisions to safeguard the long-term sustainability of fish resources., (© 2024. The Author(s).)

The construction of dams and hydroelectric plants affects biodiversity in aquatic environments and can facilitate the invasion of species. Few studies assess the long-term response of parasite fauna under these events. The aim of this study was to investigate possible changes in the endoparasite composition of the invasive catfish Trachelyopterus galeatus (Linnaeus, 1766) in the floodplain of the upper Paraná River over a 27-year study period. A total of 79 fish were collected in period 1 (1993) and 31 in period 2 (2019/2020) at the same sampling points, and the endoparasites were located in the gastrointestinal system using a stereomicroscope. It was found that the development of the fish and the composition of their endoparasitic fauna changed over time. In the second period, the fish presented smaller values for mass (g) and standard length (cm) when compared to period 1. It was found that three species of endoparasites were found per period, but although the richness was the same, the composition differed, and only one digenean (Microrchis oligovitellum Lunaschi, 1987 (Trematoda: Paramphistomidae)) was shared. The Porto Primavera Dam was built upstream of the site between the sampling periods (1999) and caused a number of environmental changes, possibly being the main factor responsible for changes in components of the parasite community. Anthropic modification to an environment can cause loss of diversity and loss of ecological interactions. Through our results, we emphasize the importance of including parasite fauna in studies that assess environmental impacts., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Among parasites of the digestive tract of the black-headed gull (Chroicocephalus ridibundus) in Poland, the best known are species of digenetic trematodes and cestodes. Nematodes of this bird species are not well known. Black-headed gulls, due to their varied diet, migration, life in a flock, and changes of habitat, can become infected with various species of helminths, and like synanthropic birds, they can spread the dispersal stages of parasites across urban and recreational areas. In the present study, an attempt was made to identify the helminth fauna of C. ridibundus from breeding colonies in north-central Poland. The aim of the study was to describe the taxonomic structure of parasites of the digestive tract of the black-headed gull and determine the quantitative parameters of their occurrence. A total of 43 black-headed gulls were examined post-mortem for gastrointestinal helminths, resulting in the identification of four cestodes (Paricterotaenia porosa, Lateriporus clerci, Anomotaenia micracantha, and Wardium fusum), three trematodes (Diplostomum pseudospathaceum, Plagiorchis laricola, and Apophallus muehlingi), and three nematodes (Eucoleus contortus, Cosmocephalus obvelatus, and Porrocaecum ensicaudatum). Lateriporus clerci (in adult form), C. obvelatus and P. ensicaudatum (in larval form) were recorded for the first time in the black-headed gull in Poland., (© 2024. The Author(s).)

A new spionid polychaete, Spio pigmentata sp. nov., is described from the southern and western coasts of Korea. This new species differs from its congeners by the combination of the following morphological characteristics: the presence of orange-brown pigmentation on the anterior part of the prostomium, black pigmentation on the peristomium and along the body, U-shaped nuchal organs, a comparatively long extension of metameric dorsal ciliated organs, three pairs of white dots per chaetiger, two to three posterior abranchiate chaetigers, and the presence of tridentate neuropodial hooded hooks. The partial 16S ribosomal DNA (rDNA) and nuclear 18S rDNA sequences of the new species and Spio sp. 2 reported by Abe and Sato-Okoshi (2021) from Japan showed high similarity, indicating that these two specimens belong to the same species. A detailed description and illustrations of the new species, together with molecular information, are provided. [ABSTRACT FROM AUTHOR]

The bent-toed geckos of the Cyrtodactylus pulchellus group are widely distributed along the Thai-Malay Peninsula. Although taxonomic and phylogenetic studies of this species group have been continuously conducted, only some populations from Thailand have been included, resulting in hidden diversity within this group. In this study, we used morphological and molecular data to clarify the taxonomic status and describe a new population from Tarutao Island, Satun Province, southern Thailand. Cyrtodactylus stellatus sp. nov. can be distinguished from its congeners by the combination of the following morphological characters: body size; tuberculation; number of dark body bands, ventral scales, and femoroprecloacal pores in males; presence of precloacal pores in females; and scattered pattern on dorsum. Phylogenetic analyses of the mitochondrial ND2 gene recovered the new species as the sister species to C. astrum, with an uncorrected pairwise divergence of 9.78-12.37%. Cyrtodactylus stellatus sp. nov. is currently only known from Tarutao Island, Thailand. The discovery of this species suggests that the diversity within the C. pulchellus group remains underestimated and future exploration of unsurveyed areas are needed to further the understanding of this group and its geographic range. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sporocysts and cercariae corresponding morphologically to those of monorchiids are reported from vermetid gastropods. • These are the first monorchiid intramolluscan stages from gastropods and represent a striking intermediate host shift. • All other known monorchiid life cycles use a bivalve first intermediate host. • The infections are genetically matched to two species of Hurleytrematoides , H. loi and H. morandi. • The exceptional feeding biology of vermetids might be key in their adoption of some trematode groups. The trematode superfamily Monorchioidea comprises three families of teleost parasites: the Monorchiidae Odhner, 1911, Lissorchiidae Magath, 1917, and Deropristidae Cable & Hunninen, 1942. All presently known lissorchiid and deropristid life cycles have gastropods as first intermediate hosts, whereas those of monorchiids involve bivalves. Here, we report an unexpected intermediate host for monorchiids; two species of Hurleytrematoides Yamaguti, 1954 use gastropods as first intermediate hosts. Sporocysts and cercariae were found infecting two species of the family Vermetidae, highly specialised sessile gastropods that form calcareous tubes, from two locations off the coast of Queensland, Australia. These intramolluscan infections broadly corresponded morphologically to those of known monorchiids in that the cercariae have a spinous tegument, oral and ventral suckers, a simple tail and distinct eye-spots. Given the simplified morphology of intramolluscan infections, genetic data provided a definitive identification. ITS2 rDNA and cox 1 mtDNA sequence data from the gastropod infections were identical to two species of Hurleytrematoides , parasites of butterflyfishes (Chaetodontidae); Hurleytrematoides loi McNamara & Cribb, 2011 from Moreton Bay (south-eastern Queensland) and Heron Island (southern Great Barrier Reef) and Hurleytrematoides morandi McNamara & Cribb, 2011 from Heron Island. Notably, species of Hurleytrematoides are positioned relatively basal in the phylogeny of the Monorchiidae and are a sister lineage to that of species known to infect bivalves. Thus, the most parsimonious evolutionary hypothesis to explain infection of gastropods by these monorchiids is that basal monorchiids (in our analyses, species of Cableia Sogandares-Bernal, 1959, Helicometroides Yamaguti, 1934 and Hurleytrematoides) will all prove to infect gastropods, suggesting a single host switching event into bivalves for more derived monorchiids (17 other genera in our phylogenetic analyses). A less parsimonious hypothesis is that the infection of vermetids will prove to be restricted to species of Hurleytrematoides , as an isolated secondary recolonisation of gastropods from a bivalve-infecting lineage. Regardless of how their use arose, vermetids represent a dramatic host jump relative to the rest of the Monorchiidae, one potentially enabled by their specialised feeding biology. [ABSTRACT FROM AUTHOR]

This is the first confirmed report of Pholeter gastrophilus infecting three delphinid species from Brazilian waters, Steno bredanensis, Tursiops truncatus, and Feresa attenuata. The worms were identified based on morphological and molecular data using the 28S rDNA and COI mtDNA genes. The present study increases the distribution area of this trematode species and provides new molecular data to be used in future phylogenetic studies of the group, thus contributing to scientific knowledge on marine parasites. [ABSTRACT FROM AUTHOR]

The Siamese shield leech (Placobdelloides siamensis) is one of the external parasites found in snail-eating turtles (Malayemys macrocephala and Malayemys subtrijuga). It has a muscular proboscis with numerous needle-like tips for penetrating the host body, and its consumption of blood and tissues differs from arhynchobdellid leeches that use a jaw tearing strategy. Dorsal coloration is attributed to pigment cells under the dorsal muscular layer, while the absence of pigment on the ventral side indicates transparency. Morphology and histology reveal the parental care behavior of this glossiphoniid leech, with the juveniles using their caudal sucker to attach an annulus around the ventral groove of the parent. Further, the histological structure of the posterior part demonstrates the presence of four contributing muscle fibers and chloragogen cells on the caudal sucker. Hence, this first report provides increasing morphological and histological knowledge of this leech for use as a representative model of a glossiphoniid leech. [ABSTRACT FROM AUTHOR]

Most migratory aquatic birds are regarded as reservoir hosts for many parasitic diseases, including digenetic trematodes that cause significant losses to farmed fish. However, in Tanzania, studies of birds focus more on their species diversity and patterns of speciation than their parasites. The current study attempted to use molecular methods, mitochondrial DNA (mtDNA), cytochrome c oxidase subunit I (COX-1) in particular, and ribosomal DNA (rDNA) i.e. 28S rRNA and internal transcribed spacer (ITS1-5.8S-ITS2) regions, to investigate the occurrence of intestinal echinostomatoid species recovered from fish-eating birds, i.e. Grey Herons (Ardea cinerea) and Great Cormorants (Phalacrocorax carbo), from Mwanza Gulf in Lake Victoria. Both morphology and molecular markers revealed the presence of three echinostomatoid species: Stephanoprora amurensis and Petasiger phalacrocoracis in P. carbo, and the Patagifer vioscai in A. cinerea. The present species are reported for the first time in African bird species. [ABSTRACT FROM AUTHOR]

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The trematode Bolbophorus damnificus (Digenea: Bolbophoridae) has caused significant economic losses since the late 1990s, with deleterious effects on production efficiency in farm‐raised catfish. Previous work has demonstrated that even mild outbreaks, which may go unnoticed by producers, can result in over 60% reduction in net economic returns. Although transmission rates in Channel Catfish Ictaluruspunctatus and hybrid catfish (Channel Catfish × Blue Catfish Ictalurus furcatus) are similar in controlled studies, anecdotal industry reports imply that the impacts of B. damnificus on hybrid catfish are less severe. In this study, mortality in juvenile Channel and hybrid catfish exposed to B. damnificus was evaluated in two discrete, replicated infectivity challenges. Mortality curves in Channel and hybrid catfish were consistent with trends previously established for B. damnificus in Channel Catfish, although in both challenges cumulative mortality was significantly lower in hybrids. All exposed fish presented clinical signs consistent with B. damnificus infection—namely lethargy, exophthalmia, distended abdomens, and metacercariae grossly visible below the skin. No mortality occurred and no parasites were observed in control fish. The biological and economic implications of these findings on catfish production are unknown but suggest that hybrid catfish are less susceptible to the deleterious effects and reduced productivity elicited by B. damnificus in Channel Catfish. [ABSTRACT FROM AUTHOR]

Background: Many annelids, including well-studied species such as Platynereis, show similar structured segments along their body axis (homonomous segmentation). However, numerous annelid species diverge from this pattern and exhibit specialised segments or body regions (heteronomous segmentation). Recent phylogenomic studies and paleontological findings suggest that a heteronomous body architecture may represent an ancestral condition in Annelida. To better understand the segmentation within heteronomous species we describe the myogenesis and mesodermal delineation of segments in Siboglinum fiordicum during development. Results: Employing confocal and transmission electron microscopy we show that the somatic longitudinal musculature consists of four separate strands, among which ventrolateral one is the most prominent and is proposed to drive the search movements of the head of the late metatrochophore. The somatic circular musculature lies inside the longitudinal musculature and is predominantly developed at the anterior end of the competent larva to support the burrowing behaviour. Our application of transmission electron microscopy allows us to describe the developmental order of the non-muscular septa. The first septum to form is supported by thick bundles of longitudinal muscles and separates the body into an anterior and a posterior region. The second group of septa to develop further divides the posterior body region (opisthosoma) and is supported by developing circular muscles. At the late larval stage, a septum reinforced by circular muscles divides the anterior body region into a forepart and a trunk segment. The remaining septa and their circular muscles form one by one at the very posterior end of the opisthosoma. Conclusions: The heteronomous Siboglinum lacks the strict anterior to posterior sequence of segment formation as it is found in the most studied annelid species. Instead, the first septum divides the body into two body regions before segments are laid down in first the posterior opisthosoma and then in the anterior body, respectively. Similar patterns of segment formation are described for the heteronomous chaetopterid Chaetopterus variopedatus and serpulid Hydroides elegans and may represent an adaptation of these annelids to the settlement and transition to the sedentarian-tubiculous mode of life. [ABSTRACT FROM AUTHOR]

We describe a large gecko of genus Hemidactylus from the southern face peneplain foothills of the Central Highlands of Sri Lanka. It closely resembles Hemidactylus hunaeDeraniyagala 1937 but is distinguished by adult males reaching 121.2 mm snout–vent length; presence of 11 or 12 supralabials at the midorbit position; dorsal scalation of homogeneous granules intermixed with large, conical, carinate tubercles that form 12–14 irregularly arranged longitudinal rows at midbody; dorsal furrow distinct with a narrow space between medial parasagittal rows; 3 or 4 pairs of postmentals; no spine-like tubercles on nape; ventrals in 36–39 rows at midbody; 21–24 femoral pores on each side separated medially by 5–7 nonpored enlarged scales; scales on posterior thigh granular, not enlarged; lamellae divided, 12 or 13 below the fourth toe; tail segmented with whorls of lateral tubercles, with each whorl consisting of 6 enlarged, conical, carinate tubercles; median row enlarged and broad; single postcloacal tubercle (spur) on each side; and body dorsum with a series of black edged bright saddles from occiput to tail tip. Additionally, we provide a redescription for H. hunae based on its adult female holotype. [ABSTRACT FROM AUTHOR]

Purpose: Describe a new species of didymozoid digenean Neonematobothrium Yamaguti, 1965 from the operculum of the scombrid fish, Euthynnus alletteratus (Rafinesque, 1810), in the Southwest Atlantic Ocean off Brazil. Methods: Thirty-four specimens of E. alletteratus were collected in the coastal zone of the state of Rio de Janeiro and obtained from local fishermen between 2006 and 2018 in the municipal market of São Pedro in Niterói, Brazil. The parasites were fixed in AFA (93% ethanol 70%, 5% formaldehyde, 2% glacial acetic acid) without pressure, stained with Langeron alcoholic acid carmine, dehydrated in an alcohol series, cleared in beachwood creosote or clove oil and mounted in Canada balsam as permanent slides. Results: Neonematobothrium annakohnae n. sp. is a member of the genus based on a combination of the following characteristics: body free, uncapsulated; body long and dorsoventrally flattened; esophagus surrounded by gland cells; ovary and vitellarium single, long, narrow and unbranched in the anterior and posterior halves of the body, respectively; uterus with three loops; and site of infection in subcutaneous tissue of scombrid fish. The new species differs from the two recognized species of the genus mainly by the size of the body, which is much larger, the shape of the genital pore, which is differentiated in a structure similar to a small sucker and by esophagus without diverticula. Conclusions: Neonematobothrium annakohnae n. sp. parasite of E. alletteratus from the Southwest Atlantic Ocean, described herein, represents the third species of Didymozoidae belonging to the genus Neonematobothrium. The two known species Neonematobothrium kawakawa Yamaguti, 1965 and Neonematobothrium dorsale Yamaguti, 1970 were described from fish belonging to the same genus of the host from Pacific Ocean. The diagnosis of the genus is enlarged to "esophagus with or without diverticula", to fill the characteristics presented by the new species. The description of N. annakohnae n. sp. demonstrates the need to expand the studies of these interesting and intriguing group of parasites, due to the fact that number of known didymozoids taxa in the Atlantic Ocean is far from representing the real situation. [ABSTRACT FROM AUTHOR]

Purpose: The intertidal and supratidal coastal zone challenges the osmoregulatory capacity of aquatic inhabitants. Four new species of Gyrodactylus ectoparasites on two intertidal fishes from Chile are described based on molecular and morphological analyses. Methods: Monogeneans were found from two fish species, the clingfish Sicyases sanguineus Müller & Troschel, 1843 and the combtooth blenny Scartichthys viridis Valenciennes, 1836. The morphology was described by drawings, and minimal measurements. The parasites were barcoded via the sequencing of the ribosomal DNA over ITS1-5.8S-ITS2. Results: The air-breathing clingfish S. sanguineus carried Gyrodactylus amphibius sp. nov., hiding in the ventral sucker formed by the modified pectoral fins of the fish. The intertidal combtooth blenny S. viridis carried three other new species: Gyrodactylus scartichthi sp. nov., Gyrodactylus viridae sp. nov., and Gyrodactylus zietarae sp. nov. Conclusion: The four new species were all phylogenetically related with the previously described G. chileani Ziętara et al. 2012 on triplefin Helcogrammoides chilensis Cancino, 1960 in the same habitat. Thus, the five Chilean Pacific Gyrodactylus species formed a statistically well-supported (100%) monophyletic clade together with three geographically distant species recorded in Europe. The Chilean Pacific parasites are not related to G. salinae and G. magadiensis, parasites described in extreme osmotic stress environments earlier. [ABSTRACT FROM AUTHOR]

Two new species of philometrid nematodes (Philometridae), Barracudia notabilis n. sp. and Philometra consimilis n. sp., are described from males found in the ovary of the hound needlefish Tylosurus crocodilus (Péron et Lesueur) (Belonidae) from off the Atlantic coast of Florida, USA. Both species are described and illustrated based on light and scanning electron microscopical examinations. Barracudia notabilis n. sp., the first representative of this genus from fishes in the Atlantic Ocean, can be differentiated from other congeners by the body length of the male (2.69 mm), the length of the gubernaculum (57 μm) and spicules (81 μm), and by the shape of the gubernaculum. Philometra consimilis n. sp. differs from all congeners mainly in the unique structure of the distal tip of the gubernaculum (bearing two smooth dorsal barbs) and the species is also characterized by the length of spicules (111 μm) and the length of the gubernaculum (84 μm). Further studies are needed to discover and describe so far unknown gravid females of Barracudia spp. [ABSTRACT FROM AUTHOR]

Abstract Centrocestus formosanus is a digenean parasite first described from Asia, which parasitizes Melanoides tuberculata (Gastropoda: Thiaridae) at the first intermediate stage, and different fish species as second intermediate host. C. formosanus was previously recorded in Brazilian states, but never before in the southern region of this country. Recording and identification of digenean species through morphological identification is a taxonomic challenge. In light of this, we use an integrative taxonomic approach to report the occurrence of cercariae and metacercariae of C. formosanus in molluscs and fish, respectively, in an urban park located in southern Brazil. Specimens of M. tuberculata and the fishes Poecilia reticulata and Xiphophorus sp. (Poeciliidae) were collected for screening for parasites and molecular analyses using partial fragments of the 28S rDNA gene. The identification of C. formosanus obtained from molluscs and fish specimens permitted us to partially solve the life cycle of this parasite for the first time in the studied environment, demonstrating the necessity of monitoring and controlling molluscs populations. Nevertheless, our results will support future studies aiming to elucidate the life-cycle of C. formosanus in this region, since all sampled hosts’ species are invasive in this environment.

The larvae of the fresh-water mite Limnochares aquatica (L., 1758) feeding on the pond-skaters Gerris lacustris (L. 1758) and their stylostome were studied using laboratory observations, light-microscope, SEM and TEM methods. The emergence of unfed larvae from the eggshell in the laboratory was also traced. Larvae possess a lamellar area on the ventral surface of the hypostome (supposed sucker or velum), which adheres to the host cuticle during feeding. The bifurcated palpal claws do not pierce the host cuticle and remain outside it during the larval feeding. The larvae secrete at least two saliva portions – the initial one gradually penetrating the host cuticle to which the cheliceral movable digits firmly adhere, and the main one forming the stylostome as such situated underneath the host cuticle. The developed stylostome does not immerse deep into the body cavity and is represented by associations of the uniformly electron-dense globules, the largest of which are pierced by the axial canal. This type of stylostome may be conventionally identified as unclearly ramified structured totally composed of the saliva secretion. The host tissue is partly destructed by the parasite saliva action, and the host defence reaction is imperceptible. The observed stylostome structure may be considered as an initial form for the fresh-water mite branch of the Parasitengona. [ABSTRACT FROM AUTHOR]

Using the immunocytochemical method and confocal scanning laser microscopy, we obtained pioneering data on the muscle system organization and presence and localization of biogenic amine serotonin and FMRFamide-related peptides in the nervous system of the trematode Prodistomum alaskense (Ward and Fillingham, 1934) Bray and Merrett 1998 (family Lepocreadiidae). This flatworm is an intestinal parasite of endemic representatives of the marine fauna of the northwestern Pacific Ocean — the prowfish (Zaprora silenus Jordan, 1896) and the lumpfish (Aptocyclus ventricosus (Pallas, 1769)). We provide data of scanning electron microscopy on the tegumental topography of P. alaskense. The body wall musculature of P. alaskense has three layers of muscle fibres — the outer circular, intermediate longitudinal, and inner diagonal. The muscle system elements are well developed in the attachment organs, digestive and reproductive systems, and in the excretory sphincter. Serotonin– and FMRFamide–immunopositive neurons and neurites are found in the head ganglia, circular commissure, longitudinal nerve cords, and in the transversal connective commissures. The innervation of the oral and ventral suckers, pharynx, and the reproductive system compartments by the serotonergic and FMRFamide–immunopositive neurites is revealed. The results discus connection with the published data on the presence and functional roles of the serotonin and FMRFamide-related peptides in Platyhelminthes. [ABSTRACT FROM AUTHOR]

The genus Clinostomum has been recently a subject of a large number of molecular phylogenetic studies that have uncovered a larger species diversity than we thought. In Argentina, only two nominal species have been reported, namely C. detruncatum and C. marginatum. Three putative species represented by metacercariae were recently molecularly diagnosed, and there are at least two additional metacercarial morphotypes diagnosed on morphological grounds. Here, we molecularly characterized specimens of Clinostomum sampled from freshwater fishes and fish-eating birds from Argentina through mtDNA cytochrome c oxidase subunit I (COI). Unexpectedly, the phylogenetic analysis uncovered three new additional genetic lineages, two of them corresponding to metacercarial stages and another matching COI sequences of C. heluans Braun, 1899, being considered conspecific, whereas the others still require formal description. Additionally, we add a new host species for a lineage molecularly diagnosed in a previous study. The adult specimens recovered from A. cocoi in Buenos Aires Province represented a new species clearly distinguished from the two species previously reported in Argentina. Clinostomum detruncatum is distinguished from the new species by possessing a characteristic tenoidean uterus, and testes located more posteriorly. Clinostomum marginatum is morphologically similar but differs from the new species in having rounded ovary, posterior testis lobated, and lateral cirrus-sac and displacing the anterior testis, and vitelline follicles not extending beyond the caeca end. Our study raises the number of Clinostomum species in Argentina up to 10. We describe the new species herein. [ABSTRACT FROM AUTHOR]

Acanthoparyphium shinanense n. sp. (Digenea: Echinostomatidae) is described from chicks experimentally infected with the metacercariae encysted in 2 brackish water clam species, Ruditapes philippinarum and Coecella chinensis, in the Republic of Korea. The metacercariae were round to oval, armed with 23 collar spines, and 0.216 (0.203-0.226) mm in diameter. From 5 chicks experimentally infected each with 200 metacercariae, 34 juvenile (5-day-old worms) and 104 adult flukes (7-day-old worms) were harvested from their small intestines, with the average worm recovery rate of 13.8%. The adult flukes were 3.18 (2.89-3.55) mm long and 0.68 (0.61-0.85) mm wide, with an elongated, posteriorly tapering body, and a prominent head collar armed with 23 collar spines arranged in a single uninterrupted row. The posterior testis of A. shinanense was longitudinally elongated, which is similar to Acanthoparyphium spinulosum Johnston, 1917 but unique from the other closely related species, including Acanthoparyphium tyosenense Yamaguti, 1939, Acanthoparyphium kurogamo Yamaguti, 1939, and Acanthoparyphium marilae Yamaguti, 1934. The eggs of A. shinanense were larger than those of A. spinulosum, and the anterior extent of 2 lateral groups of vitellaria was slightly more limited in A. shinanense than in A. spinulosum. Molecular analysis of nuclear and mitochondrial genes revealed low homology with A. spinulosum from USA (96.1% in 5.8S rRNA) and Ukraine (97.9% in 28S rRNA), Acanthoparyphium n. sp. from USA (98.0% in 28S rRNA), and Acanthoparyphium sp. from Australia, Kuwait, and New Zealand. Biological characteristics, including its first intermediate host and natural definitive hosts, as well as its zoonotic capability, should be elucidated. [ABSTRACT FROM AUTHOR]

Members of Forticulcitinae Blasco-Costa, Balbuena, Kostadinova & Olson, 2009 include endoparasites of mullet fishes distributed worldwide. Adult specimens were collected from the intestines of white mullet (Mugil curema) and flathead grey mullet (Mugil cephalus) from five localities in the Gulf of Mexico and a single locality in Venezuela. Photogenophores were sequenced for two nuclear molecular markers, the large subunit (LSU) and second internal transcribed spacer (ITS2) of nuclear rDNA. The new sequences were aligned with other sequences downloaded from GenBank. The maximum likelihood and Bayesian inferences were deduced using the combined dataset (LSU + ITS2). The phylogenetic analyses revealed four new lineages belonging to Forticulcitinae. Three new species are described in the present study. Ekuarhuni mexicanusn. sp. can be differentiated from its congeneric species by presenting a longer hermaphroditic sac length (136–180 μm) and a wider testis (91–123 μm). Forticulcita macropharyngisn. sp. and Forticulcita venezuelensisn. sp. are the 8th and 9th species described in Forticulcita. Both species belong to the diminutive morphotype of Forticulcita. Forticulcita macropharyngisn. sp. can be morphologically distinguished from the other congeneric species by the presence of a massive and muscular pharynx (46–110 μm long, 74–106 μm wide). Forticulcita venezuelensisn. sp. is the second species of the studied genus recorded in South America and can be differentiated from congeneric species by possessing the largest testis (138–201 μm long, 83–100 μm wide). Finally, the fourth lineage corresponds to Overstreetoides Andrade-Gómez & García-Varela, 2021; however, few specimens of this lineage were collected, precluding any description of the species. In addition, a key is proposed for differentiating the genera and species of Forticulcitinae. [ABSTRACT FROM AUTHOR]

[Display omitted] • The presence of Apharyngostrigea pipientis in Nearctic, Neotropic and Afrotropic regions shown using CO1. • First known report of A. pipientis in Africa, but no evidence of recent introduction. • First known experimental demonstration of A. pipientis compatibility with a teleost second intermediate host. • Molecular links were found among all life-cycle stages of A. pipientis and Apharyngostrigea simplex. • The whole mitogenome and rDNA operon of A. pipientis show paraphyly in Strigeidae. When subjected to molecular study, species of digeneans believed to be cosmopolitan are usually found to consist of complexes of species with narrower distributions. We present molecular and morphological evidence of transcontinental distributions in two species of Apharyngostrigea Ciurea, 1924, based on samples from Africa and the Americas. Sequences of cytochrome c oxidase I and, in some samples, internal transcribed spacer, revealed Apharyngostrigea pipientis (Faust, 1918) in Tanzania (first known African record), Argentina, Brazil, USA and Canada. Sequences from A. pipientis also match previously published sequences identified as Apharyngostrigea cornu (Zeder, 1800) originating in Mexico. Hosts of A. pipientis surveyed include definitive hosts from the Afrotropic, Neotropic and Nearctic, as well as first and second intermediate hosts from the Americas, including the type host and type region. In addition, metacercariae of A. pipientis were obtained from experimentally infected Poecilia reticulata , the first known record of this parasite in a non-amphibian second intermediate host. Variation in cytochrome c oxidase I haplotypes in A. pipientis is consistent with a long established, wide-ranging species with moderate genetic structure among Nearctic, Neotropic and Afrotropic regions. We attribute this to natural dispersal by birds and find no evidence of anthropogenic introductions of exotic host species. Sequences of CO1 and ITS from adult Apharyngostrigea simplex (Johnston, 1904) from Egretta thula in Argentina matched published data from cercariae from Biomphalaria straminea from Brazil and metacercariae from Cnesterodon decemmaculatus in Argentina, consistent with previous morphological and life-cycle studies reporting this parasite—originally described in Australia—in South America. Analyses of the mitochondrial genome and rDNA operon from A. pipientis support prior phylogenies based on shorter markers showing the Strigeidae Railliet, 1919 to be polyphyletic. [ABSTRACT FROM AUTHOR]

Parasites are important components of ecosystems, thus identifying patterns of their diversity is crucial for studies investigating ecosystem functioning, food web structure, trophic interactions and epidemiological parameters. Via an integrative taxonomic approach, we studied the diversity and distribution of trematodes of the genus Plagiorchis Lühe, 1899 in snails in the sub‐Arctic freshwater ecosystems of Iceland and for comparative purposes in West and North Europe (Ireland and Finland, respectively), supplemented by data from Alaska, USA, all regions with remarkably few data on trematode diversity. Molecular genetic and morphological analyses of 68 samples of cercarial isolates of Plagiorchis collected from 3,069 snails belonging to six species revealed a total of 16 species/species‐level lineages of Plagiorchis with five found in Iceland, six in Finland, nine in Ireland and five in Alaska. Two species‐level lineages found in Iceland, Finland and Ireland were reported for the first time; for all species/species‐level lineages identified by DNA sequences we provide the first morphological characterization. Our analysis of the diversity of Plagiorchis and their snail host spectrum in Europe provides evidence for Radix balthica and Lymnaea stagnalis as primary first intermediate hosts. By comparing DNA sequence data for Plagiorchis spp. from this and previous studies, we demonstrate no overlapping spatial distribution for members of the genus in our material between the continents of Europe and North America. We infer that the spatial distribution of Plagiorchis spp. is constrained mainly by migratory birds' ranges. Finally, in Europe, further research is needed to evaluate whether the diversity of Plagiorchis spp. in R. balthica is unique to high latitude ecosystems. [ABSTRACT FROM AUTHOR]

Devonian orthotetides from South America have often been uncritically assigned to a limited number of broadly described species. Schellwienella clarkei n. sp. is described from the Ponta Grossa Formation, Paraná Basin, southern Brazil. These brachiopods had been identified as Schuchertella agassizi. Schellwienella clarkei n. sp. differs from Schuchertella agassizi on the basis of shell structure, dental plates, and cardinalia. UUID: http://zoobank.org/90ebc242-42c3-4bd7-9b63-461df05b6f28 [ABSTRACT FROM AUTHOR]