Pipimorpha and its crown-group Pipidae possess one of the most extensive fossil records among anurans, which extends into the Early Cretaceous in both Laurasia and Gondwana. This is probably linked to the highly aquatic lifestyle of pipids, which is probably also characteristic of early pipimorphs. In South America, pipids are currently represented only by Pipa, but the fossil record documents an evolutionary radiation of Shelaniinae (a taxon endemic to South America) in the Cretaceous; shelaniines seem to have become extinct in the Eocene. Fewer pipimorph fossils are known from Africa. Our recent redescription of the mid-Late Cretaceous (Coniacian–Santonian) taxon Pachycentrata taqueti from In Becetèn (Niger) partly fills this gap. Our new phylogenetic analysis of Cretaceous and Paleogene pipimorphs shows that this taxon diversified in a West Gondwanan block until about the mid-Cretaceous, but after that, pipimorphs show two distinct evolutionary radiations, one in South America (Pipinae), and the other (Xenopodinae) in Africa. This pattern appears to reflect the breakup of West Gondwana simultaneously with the opening of the South Atlantic during the Cretaceous. This probable vicariant pattern yields slightly different ages for the South Atlantic opening depending on the accepted topology. The tree constrained to reflect the topology of extant taxa supported by molecular data shows a last dispersal between both continents before the Cenomanian (more than 100 Ma), whereas the unconstrained topology that reflects only morphological data is compatible with a more recent last faunal dispersal among pipids. Under this unconstrained topology, the fossil record is too poor to give a reliable minimal age for this last dispersal, but molecular dating analyses suggest that this event harks back to the Mesozoic.
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RBINS Staff Publications 2024 OA
Introduction: Swimmer's itch (or cercarial dermatitis) is caused by avian and mammalian blood flukes, a parasitic infection affecting people worldwide. In particular, avian blood flukes of the genus Trichobilharzia, including Trichobilharzia regenti, are known for causing swimmer's itch. While these parasites typically infect waterfowl as final hosts, incidental infections in humans by cercariae can occur. Such infections trigger immune responses leading to painful, itchy skin lesions. In experimental animals, T. regenti has however shown the ability to evade immune responses, causing neuroinflammation. Recent decades have witnessed an increase in swimmer's itch cases across Europe, turning it into an emerging zoonosis. Methods: Following a swimmer's itch case in Kampenhout (Belgium) in 2022, a malacological and parasitological survey was conducted at the transmission site, consisting of a private pond and adjacent creek. Results: Six snail species were collected, including Ampullaceana balthica, a common intermediate host for Trichobilharzia parasites. Shedding experiments and DNA barcoding identified one snail specimen infected with T. regenti, a new species record for Belgium. This finding further strengthens the link between T. regenti and cercarial dermatitis. Additionally, Echinostomatidae sp. and Notocotylus sp. were isolated from other A. balthica specimens. However, the absence of reference DNA sequences hindered genus- and species-level identification for these parasites. Conclusions: The presence of T. regenti in Belgium may have significant clinical implications, emphasizing the need for heightened diagnostic awareness among medical professionals. The lack of species-level identification for other parasite species underscores the need for comprehensive DNA databases for trematodes. These findings reveal the necessity for a Belgian framework to promptly detect and monitor zoonotic outbreaks of trematode parasites within the One Health context.
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RBINS Staff Publications 2025
