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Despite their important ecological role, questions remain on mechanisms structuring parasite assemblages. We present an endemic and species‐poor parasite–host system of two species of clupeid fishes Limnothrissa miodon, Stolothrissa tanganicae) and two species of monogenean parasites (Kapentagyrus, Dactylogyridae) from Lake Tanganyika as a model to study parasite distribution patterns and co‐infection dynamics in nature. We modelled spatiotemporal dynamics of parasite–host interaction using infection data along the north–south axis of Lake Tanganyika (660 km) over the course of two seasons and four years (1730 fish, 3710 parasites). We found temporal stability of parasite infection, which contrasts with previously reported seasonally driven fluctuations of fish host abundances. We found a difference in spatial structure between the parasite species which follows the contrasting dispersal pattern of their respective host species. On L. miodon, the host species that is infected by the two parasite species, we discovered a positive correlation with host body size for one parasite species, and a negative correlation for the other species. The apparent host‐size related replacement in the two parasite species infecting L. miodon contrasts with the beneficial influence that each of the parasite species has on the other. Parasites have been reported in previous studies to change habitat depending on host size/age. Differences in abundance and prevalence here reported between parasite species infecting the same host species related to the host body length further illustrate the parasites' dependence on changes in lifestyle of the host during its ontogenetic development. Also, possible mechanisms underlying the reported facilitation of infection are discussed. In conclusion, we show that in this closed, species‐poor system parasite infection dynamics are dependent on a combination of host mobility, host lifestyle changes over ontogenetic development, and interspecific interactions between parasites. [ABSTRACT FROM AUTHOR]

A substantial portion of biodiversity has evolved through adaptive radiation. However, the effects of explosive speciation on species interactions remain poorly understood. Metazoan parasites infecting radiating host lineages could improve our knowledge because of their intimate host relationships. Yet limited molecular, phenotypic and ecological data discourage multivariate analyses of evolutionary patterns and encourage the use of discrete characters. Here, we assemble new molecular, morphological and host range data widely inferred from a species‐rich lineage of parasites (Cichlidogyrus, Platyhelminthes: Monogenea) infecting cichlid fishes to address data scarcity. We infer a multimarker (28S/18S rDNA, ITS1, COI mtDNA) phylogeny of 58 of 137 species and characterize major lineages through synapomorphies inferred from mapping morphological characters. We predict the phylogenetic position of species without DNA data through shared character states, a morphological phylogenetic analysis, and a classification analysis with support vector machines. Based on these predictions and a cluster analysis, we assess the systematic informativeness of continuous characters, search for continuous equivalents for discrete characters, and suggest new characters for morphological traits not analysed to date. We also model the attachment/reproductive organ and host range evolution using the data for 136 of 137 described species and multivariate phylogenetic comparative methods (PCMs). We show that discrete characters not only can mask phylogenetic signals, but also are key for characterizing species groups. Regarding the attachment organ morphology, a divergent evolutionary regime for at least one lineage was detected and a limited morphological variation indicates host and environmental parameters affecting its evolution. However, moderate success in predicting phylogenetic positions, and a low systematic informativeness and high multicollinearity of morphological characters call for a revaluation of characters included in species characterizations. [ABSTRACT FROM AUTHOR]

Many species‐rich ecological communities emerge from adaptive radiation events. Yet the effects of adaptive radiation on community assembly remain poorly understood. Here, we explore the well‐documented radiations of African cichlid fishes and their interactions with the flatworm gill parasites Cichlidogyrus spp., including 10,529 reported infections and 477 different host–parasite combinations collected through a survey of peer‐reviewed literature. We assess how evolutionary, ecological, and morphological parameters determine host–parasite meta‐communities affected by adaptive radiation events through network metrics, host repertoire measures, and network link prediction. The hosts' evolutionary history mostly determined host repertoires of the parasites. Ecological and evolutionary parameters predicted host–parasite interactions. Generally, ecological opportunity and fitting have shaped cichlid‐Cichlidogyrus meta‐communities suggesting an invasive potential for hosts used in aquaculture. Meta‐communities affected by adaptive radiations are increasingly specialised with higher environmental stability. These trends should be verified across other systems to infer generalities in the evolution of species‐rich host–parasite networks. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phylogenetic reconstruction of dactylogyrid monogeneans revealed two well-supported lineages and 16 well-supported clades. • The subfamilies Dactylogyrinae and Ancyrocephalinae are re-evaluated. • Baseline multi-locus alignment was used to infer the phylogenetic position of new species and genera within Dactylogyridae. Dactylogyridae is one of the most studied families of parasitic flatworms with more than 1000 species and 166 genera described to date including ecto- and endoparasites. Dactylogyrid monogeneans were suggested as model organisms for host-parasite macroevolutionary and biogeographical studies due to the scientific and economic importance of some of their host lineages. Consequently, an array of phylogenetic research into different dactylogyrid lineages has been produced over the past years but the last family-wide study was published 16 years ago. Here, we provide a meta-analysis of the phylogenetic relationships of Dactylogyridae including representatives of all genera with available molecular data (n = 67). First, we investigate the systematic informativeness of morphological characters widely used to diagnose dactylogyrid genera through a parsimony analysis of the characters, character mapping, and phylogenetic comparative methods. Second, we provide an overview of the current state of the systematics of the family and its subfamilies, and summarise potentially poly- and paraphyletic genera. Third, we elaborate on the implications of taxonomic, citation, and confirmation bias in past studies. Fourth, we discuss host range, biogeographical, and freshwater-marine patterns. We found two well-supported macroclades which we assigned to the subfamilies Dactylogyrinae and Ancyrocephalinae. These subfamilies further include 16 well-supported clades with only a few synapomorphies that could be deduced from generic diagnoses in the literature. Furthermore, few morphological characters considered systematically informative at the genus level display a strong phylogenetic signal. However, the parsimony analysis suggests that these characters provide little information on the relationships between genera. We conclude that a strong taxonomic bias and low coverage of DNA sequences and regions limit knowledge on morphological and biogeographical evolutionary patterns that can be inferred from these results. We propose addressing potential citation and confirmation biases through a 'level playing field' multiple sequence alignment as provided by this study. [ABSTRACT FROM AUTHOR]

Species interactions are a key aspect of evolutionary biology. Parasites, specifically, are drivers of the evolution of species communities and impact biosecurity and public health. However, when using interaction networks for evolutionary studies, interdependencies between distantly related species in these networks are shaped by ancient and complex processes. We propose using recent interacting host–parasite radiations, e.g. African cichlid fishes and cichlid gill parasites belonging to Cichlidogyrus (Dactylogyridae, Monogenea), as macroevolutionary model of species interactions. The cichlid–Cichlidogyrus network encompasses 138 parasite species and 416 interactions identified through morphological characteristics and genetic markers in 160 publications. We discuss the steps required to develop this model system based on data resolution, sampling bias, and reporting quality. In addition, we propose the following steps to guide efforts for a macroevolutionary model system for species interactions: first, evaluating and expanding model system outcome measures to increase data resolution; second, closing knowledge gaps to address underreporting and sampling bias arising from limited human and financial resources. Identifying phylogenetic and geographic targets, creating systematic overviews, enhancing scientific collaborations, and avoiding data loss through awareness of predatory journal publications can accelerate this process; and third, standardising data reporting to increase reporting quality and to facilitate data accessibility. [ABSTRACT FROM AUTHOR]

Based on new specimens of Myriogenospora spp. from Costa Rica and Panama, we present morphological analyses, systematic conclusions, additions to host ranges, and geographical distribution data for the two species currently classified in this genus. Myriogenospora atramentosa (Berk. & M.A. Curtis) Diehl differs from Myriogenospora linearis (Rehm) J.F. White & Glenn in the ascus and part-spore morphology, a different position in the molecular phylogeny, and the host range. We conclude that the two species are not congeneric and propose that M. linearis should be called Balansia linearis (Rehm) Diehl. [ABSTRACT FROM AUTHOR]

[Display omitted] • Monogeneans are co-introduced with invasive Nile tilapia in sub-Saharan Africa. • DNA barcoding is applied to genetically detect parasite transmissions. • Parasite transmissions occur between invasive Nile tilapia and native tilapias. • A broad host range and environmental tolerance may promote parasite transmission. • Continuous monitoring is important to understand long-term parasitological impact. Invasive Nile tilapias negatively impact native tilapia species through hybridisation and competition. However, the co-introduction of parasites with Nile tilapia, and subsequent changes in parasite communities, are scarcely documented. Monogeneans are known pathogens of cultured Nile tilapia, although little is known about their fate once Nile tilapias establish in new ecosystems. We investigate the parasitological consequences of Nile tilapia introduction on native tilapias in basins in Cameroon, the Democratic Republic of the Congo (DRC), and Zimbabwe, focusing on ectoparasitic dactylogyrids (Monogenea). Using the mitochondrial cytochrome oxidase c subunit I (COI) and nuclear 18S-internal transcribed spacer 1 (18S-ITS1) rDNA region of 128 and 166 worms, respectively, we evaluated transmission of several dactylogyrid species. Parasite spillover from Nile tilapia was detected for Cichlidogyrus tilapiae to Coptodon guineensis in Cameroon, Cichlidogyrus thurstonae to Oreochromis macrochir in the DRC, and Cichlidogyrus halli and C. tilapiae to Coptodon rendalli in Zimbabwe. Parasite spillback to Nile tilapia was detected for Cichlidogyrus papernastrema and Scutogyrus gravivaginus from Tilapia sparrmanii and Cichlidogyrus dossoui from C. rendalli or T. sparrmanii in the DRC, and Cichlidogyrus chloeae from Oreochromis cf. mortimeri and S. gravivaginus from O. macrochir in Zimbabwe. 'Hidden' transmissions (i.e. transmission of certain parasite lineages of species that are naturally present on both alien and native hosts) were detected for C. tilapiae and Scutogyrus longicornis between Nile tilapia and Oreochromis aureus and C. tilapiae between Nile tilapia and Oreochromis mweruensis in the DRC, and Cichlidogyrus sclerosus and C. tilapiae between Nile tilapia and O. cf. mortimeri in Zimbabwe. A high density of Nile tilapia occurring together with native tilapias, and the broad host range and/or environmental tolerance of the transmitted parasites, are proposed as factors behind parasite transmission through ecological fitting. However, continuous monitoring and the inclusion of environmental variables are necessary to understand the long-term consequences of these transmissions on native tilapias and to elucidate other underlying factors influencing these transmissions. [ABSTRACT FROM AUTHOR]

Ergasilidae is a family of globally distributed copepods parasitizing freshwater fishes. Despite their widespread occurrence, their phylogeographic patterns are poorly understood, specifically in the African Great Lakes. Here, we aim to provide an update on the distribution of Ergasilus kandti, a copepod species infecting Tylochromis polylepis, an endemic cichlid fish species in Lake Tanganyika, and the phylogenetic relationship of African ergasilids. We present the first record of E. kandti parasitizing the gills of T. polylepis in Lake Tanganyika proper, identified through light microscopy and, for the first time for any ergasilid, confocal laser scanning microscopy. We suggest that this technique adds spatial context to characters that are hardly visible while using light microscopy. Phylogenetic analyses based on ribosomal DNA fragments suggest two monophyletic groups of African ergasilids. However, the phylogenetic relationships of Ergasilus remain unresolved, possibly because of the insufficient resolution of these widely used phylogenetic markers and low taxonomic coverage. A comparison of ergasilid mitochondrial genomes highlights traits found in other parasite lineages including genome shrinkage and low evolutionary rates of the cox1 gene. This study presents the most extensive molecular characterization of any ergasilid species to date. [ABSTRACT FROM AUTHOR]

The origin of introduced Nile tilapia stocks in sub-Saharan Africa is largely unknown. In this study, the potential of monogeneans as a biological tag and magnifying glass is tested to reveal their hosts' stocking history. The monogenean gill community of different Nile tilapia populations in sub-Saharan Africa was explored, and a phylogeographic analysis was performed based on the mitogenomes of four dactylogyrid species (Cichlidogyrus halli , C. sclerosus , C. thurstonae , and Scutogyrus longicornis). Our results encourage the use of dactylogyrids as biological tags. The magnifying glass hypothesis is only confirmed for C. thurstonae , highlighting the importance of the absence of other potential hosts as prerequisites for a parasite to act as a magnifying glass. With the data generated here, we are the first to extract mitogenomes from individual monogeneans and to perform an upscaled survey of the comparative phylogeography of several monogenean species with unprecedented diagnostic resolution. • Parasites are helpful to explore Nile tilapia introductions in sub-Saharan Africa. • Monogeneans are used as biological tag and magnifying glass of Nile tilapia host. • Phylogeography is performed based on mitogenomes of four dactylogyrid species. • Mitogenomes are extracted from individual monogeneans for the first time. • Parasites need to be host specific to act as a magnifying glass. [ABSTRACT FROM AUTHOR]