Phylogenomics and Diversification of the Schistosomatidae Based on Targeted Sequence Capture of Ultra-Conserved Elements

Abstract

Schistosomatidae Stiles and Hassall 1898 is a medically significant family of digenetic trematodes (Trematoda: Digenea), members of which infect mammals or birds as definitive hosts and aquatic or amphibious gastropods as intermediate hosts. Currently, there are 17 named genera, for many of which evolutionary interrelationships remain unresolved. The lack of a resolved phylogeny has encumbered our understanding of schistosomatid evolution, specifically patterns of host-use and the role of host-switching in diversification. Here, we used targeted sequence capture of ultra-conserved elements (UCEs) from representatives of 13 of the 17 named genera and 11 undescribed lineages that are presumed to represent either novel genera or species to generate a phylogenomic dataset for the estimation of schistosomatid interrelationships. This study represents the largest phylogenetic effort within the Schistosomatidae in both the number of loci and breadth of taxon sampling. We present a near-comprehensive family-level phylogeny providing resolution to several clades of long-standing uncertainty within Schistosomatidae, including resolution for the placement of the North American mammalian schistosomes, implying a second separate capture of mammalian hosts. Additionally, we present evidence for the placement of Macrobilharzia at the base of the Schistosoma + Bivitellobilharzia radiation. Patterns of definitive and intermediate host use and a strong role for intermediate host-switching are discussed relative to schistosomatid diversification.

Systematics and life cycles of four avian schistosomatids from Southern Cone of South America

“…All taxa recovered from the hosts belonged to the DAS clade of avian schistosomatids ( sensu Brant & Loker, 2013; Ebbs et al ., 2022) with robust nodal support (Figure 3). Phylogenetic analysis of BI for both loci supported the morphological identification of T. querquedulae and the placement of Trichobilharzia sp.…”

“…This family is currently composed of 17 genera, 13 of which are found parasitising different orders of freshwater and marine birds (Gibson et al ., 2002; Horák et al, 2015; Flores et al ., 2021; Lorenti et al, 2022). As part of the phylogenetic clade “Derived avian schistosomes”, hereafter clade DAS ( sensu Brant & Loker, 2013), the genus Trichobilharzia Skrjabin & Zakharow, 1920 is considered the most speciose with about 40 species, mostly parasitising birds of order Anseriformes, and is globally distributed (Brant & Loker, 2009, 2013; Horák et al, 2015; Ebbs et al ., 2022).…”

Copy numbers of stress response genes reflect difference in adaptive potential of metazoan parasites

“…Aguoru et al (2022)]. With nine species of Cichlidogyrus, the study provides the most species-rich set of whole-genome sequencing data from a single genus of flatworms to date, followed only by the blood fluke genus Schistosoma with eight species (Ebbs et al, 2022). Furthermore, with 68/277 single-copy ortholog and 43 stress genes, this study is by far the most extensive genomic analysis of monogenean flatworms.…”

Hooking the scientific community on thorny-headed worms: interesting and exciting facts, knowledge gaps and perspectives for research directions on Acanthocephala

“…Using transcriptomic (EST) data, Wey-Fabrizius et al (2014) [182] explored the evolutionary relationships within the Syndermata, in which transcriptomes of one eoacanthocephalan (Paratenuisentis ambiguus) and two palaeacanthocephalans (Echinorhynchus truttae and P. laevis) were included. Targeted sequence capture of UCEs has recently been applied to address schistosomatid diversification [46]. Together with extensive taxonomic sampling, high-throughput phylogenomics should provide a robust phylogeny to apply comparative methods in the future.…”