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Purpose: The Diplostomidae is a globally distributed family of digeneans that parasitize a wide variety of tetrapod definitive hosts. Recent molecular phylogenetic studies have revealed unknown diplostomid diversity in avian hosts throughout the New World. Herein, we provide descriptions of a novel genus of diplostomids with two new species., Methods: Two species of diplostomids belonging to the new genus were collected from anhinga birds in Mississippi (USA) and Brazil. Partial nuclear 28S ribosomal and mitochondrial cox1 genes were sequenced. Ribosomal data were used for phylogenetic inference., Results: Both species of Anhingatrema n. gen. were positioned in a 100% supported, monophyletic clade in the phylogenetic tree. The molecular phylogenetic position and a combination of morphological features (e.g., presence of pseudosuckers, testes shape and orientation) supported erection of the new genus. Anhingatrema overstreeti n. sp. and Anhingatrema cararai n. sp. are morphologically similar, but differ in size of and ratios associated with pseudosuckers. The two species differ by 2% of 28S sequences and 13.8% of cox1 sequences. Comparison of DNA sequences revealed that Diplostomidae gen. sp. in GenBank (MZ314151) is conspecific with An. overstreeti n. sp., Conclusion: Anhingatrema n. gen. is the sixth genus of diplostomids known from anhingas worldwide. Anhingatrema cararai n. sp. is the first diplostomid to be reported from anhingas in South America. Combined with previous studies, the molecular phylogenies revealed at least two host switches to anhingas from other birds during the evolutionary history of the Diplostomidae., (© 2022. The Author(s) under exclusive licence to Witold Stefański Institute of Parasitology, Polish Academy of Sciences.)

Kingfishers (Alcedinidae Rafinesque) are common inhabitants of wetlands and are known to be definitive hosts to a wide range of digeneans that parasitize fish as second intermediate hosts. Among these digeneans, members of the Diplostomidae Poirier, 1886 (diplostomids) are particularly common. Recent studies of diplostomids collected from kingfishers have revealed that they are probably more diverse than currently known. This particularly concerns the genera Crassiphiala Van Haitsma, 1925 and Uvulifer Yamaguti, 1934. In the present work, we studied seven diplostomid taxa from kingfishers in Brazil, the USA and the Philippines. Partial DNA sequences of the nuclear large ribosomal subunit (28S) and mitochondrial cytochrome c oxidase I ( cox 1) genes were obtained, and 28S sequences were used to study the phylogenetic interrelationships of these diplostomids. We provide the first DNA sequences from Uvulifer semicircumcisus Dubois et Rausch, 1950 and a member of Subuvulifer Dubois, 1952. Pseudocrassiphiala n. gen. is erected for a previously recognized species-level lineage of Crassiphiala and a new generic diagnosis of Crassiphiala is provided. Crassiphiala jeffreybelli n. sp., Crassiphiala wecksteini n. sp. and Pseudocrassiphiala tulipifera n. sp. are described, and a description of newly collected, high-quality specimens of Crassiphiala bulboglossa Van Haitsma, 1925 (the type-species of the genus) is provided.

Ochoterenatrema is a small genus of lecithodendriid digeneans that includes six species parasitic in Neotropical bats in North and South America. Members of this genus are characterized by the presence of a pseudogonotyl formed by thickened tegument on the left side of the ventral sucker. We examined morphology of specimens belonging to five species of Ochoterenatrema from Brazil, Ecuador and the USA and describe two new Ochoterenatrema spp. (Ochoterenatrema sphaerula n. sp. and Ochoterenatrema gracilis n. sp.). These new species are readily differentiated from their congeners by a combination of morphological characters, including the distribution of vitelline follicles and the body shape. We have provided the first DNA sequences for Ochoterenatrema. Newly generated partial nuclear 28S rDNA and mitochondrial cox1 gene sequences were used to differentiate among species and study the phylogenetic affinities of Ochoterenatrema spp., including one of the new species, O. gracilis n. sp., as well as Ochoterenatrema diminutum, Ochoterenatrema fraternum and Ochoterenatrema cf. labda. The phylogeny of the Microphalloidea based on 28S had well-supported topology, particularly at the family level. The Ochoterenatrema clade was strongly supported; however, the internal topology of the clade was weakly supported. Comparison of sequences revealed 0.4-1.3% interspecific divergence in 28S and 9.1-19.7% interspecific divergence in cox1 among Ochoterenatrema spp. We hypothesize that extremely diverse fauna of bats in South and Central America harbors multiple undescribed species of Ochoterenatrema. Several lecithodendriid genera from bats and other hosts are yet to be included in future molecular phylogenetic analyses to test the monophyly of this extremely diverse digenean family and analyze evolutionary affinities of its constituent taxa., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Anenterotrema is a small genus of dicrocoeliids (Digenea: Dicrocoeliidae) containing 6 species found in Neotropical bats. Members of this genus are characterized by the lack of digestive system organs and, unlike the majority of dicrocoeliids, parasitize the intestine of their definitive hosts. In this study, we have morphologically examined newly collected specimens belonging to four species of Anenterotrema from Brazil, Ecuador, and Panama. Based on the data in original descriptions and our analysis of quality new specimens, we resurrected Anenterotrema freitasi, previously synonymized with A. eduardocaballeroi. We also described a new species of Anenterotrema from Molossus molossus in the Brazilian Amazon. The new species differs from congeners in several morphological features, most prominently in the size and structure of its highly muscular, protuberant ventral sucker. It is also characterized by the lack of the semi-circular thickening of the tegument around the oral sucker typical for some members of the genus. We used partial DNA sequences of the large ribosomal subunit gene (28S) and mitochondrial cytochrome c oxidase subunit 1 gene (cox1) to test the monophyly of Anenterotrema, and study the interrelationships and determine the inter- and intraspecific variation of three Anenterotrema spp. collected from different bat species in Brazil, Ecuador and Panama.

As presently recognized, Herpetodiplostomum is a small genus of proterodiplostomid digeneans parasitic in crocodilians. Most members of Cheloniodiplostomum, a genus of proterodiplostomids that parasitize chelonians, were originally placed within Herpetodiplostomum. The 2 genera were distinguished based on the presence/absence of papillae on the holdfast organ and anterior extent of vitellarium. Our study of Herpetodiplostomum and Cheloniodiplostomum revealed a lack of consistent morphological differences between the genera. Therefore, we consider Cheloniodiplostomum to be a junior synonym of Herpetodiplostomum. Recent molecular phylogenetic studies included a number of proterodiplostomid taxa; however, DNA sequence data are not available for any Herpetodiplostomum or Cheloniodiplostomum species. Herein, we describe a new Herpetodiplostomum species from Geoffroy's side-necked turtle Phrynops geoffroanus from Mato Grosso State, Brazil. The new species can be distinguished from other Herpetodiplostomum species based on the distribution of vitellarium, level of development of holdfast papillae, and ratio of prosoma:opisthosoma width, among other characters. We provide the first molecular phylogeny of the Proterodiplostomidae that includes a Herpetodiplostomum species. The limited geographic distribution of Herpetodiplostomum spp. within the geographic ranges of caimans suggests a secondary host switching event from crocodilians to chelonian definitive hosts in the evolution of Herpetodiplostomum., (© American Society of Parasitologists 2021.)

Sphincterodiplostomum is a monotypic genus of diplostomid digeneans that parasitize fish-eating birds in the neotropics. The type species Sphincterodiplostomum musculosum has a unique, dorsal, tubular invagination in the opisthosoma with a muscular sphincter. Whereas larvae of S. musculosum are relatively commonly reported in Neotropical fish helminth surveys, adult specimens from birds are rarely collected. Prior to our study, no DNA sequence data for S. musculosum were available. Our molecular and morphological study of mature and immature adult Sphincterodiplostomum specimens from three species of birds and one species of crocodilian revealed the presence of at least two species of Sphincterodiplostomum in the neotropics. We provide the first molecular phylogeny of the Diplostomoidea that includes Sphincterodiplostomum. In addition, this is the first record of S. musculosum from caimans, along with the first record of fully mature adult S. musculosum from green kingfisher Chloroceryle americana. The new species of Sphincterodiplostomum (Sphincterodiplostomum joaopinhoi n. sp.) can be morphologically distinguished from S. musculosum based on the anterior extent of vitelline follicles, narrower prosoma, substantially smaller holdfast organ and structure of tegumental spines. Our data revealed 0.7% interspecific divergence in 28S and 10.6-11.7% divergence in cox1 sequences between the two Sphincterodiplostomum species.