title: Constraining the Deep Origin of Parasitic Flatworms and Host-Interactions with Fossil Evidence.
abstract: Novel fossil discoveries have contributed to our understanding of the evolutionary appearance of parasitism in flatworms. Furthermore, genetic analyses with greater coverage have shifted our views on the coevolution of parasitic flatworms and their hosts. The putative record of parasitic flatworms is consistent with extant host associations and so can be used to put constraints on the evolutionary origin of the parasites themselves. The future lies in new molecular clock analyses combined with additional discoveries of exceptionally preserved flatworms associated with hosts and coprolites. Besides direct evidence, the host fossil record and biogeography have the potential to constrain their evolutionary history, albeit with caution needed to avoid circularity, and a need for calibrations to be implemented in the most conservative way. This might result in imprecise, but accurate divergence estimates for the evolution of parasitic flatworms.
authors.affiliation: Fachgruppe PaläoUmwelt, GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: Kenneth
authors.initials: K
authors.lastname: De Baets
authors.affiliation: Núcleo de Oceanografia Geológica, Instituto de Oceanografia, Universidade Federal do Rio Grande, Rio Grande, Brazil.
authors.forename: Paula
authors.initials: P
authors.lastname: Dentzien-Dias
authors.affiliation: Department of Geology, University of Latvia, Riga, Latvia.
authors.forename: Ieva
authors.initials: I
authors.lastname: Upeniece
authors.affiliation: Centre de Formation et de Recherche sur les Environnements Méditerranéens, University of Perpignan Via Domitia, Perpignan, France; CNRS, Centre de Formation et de Recherche sur les Environnements Méditerranéens, Perpignan, France; Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa.
authors.forename: Olivier
authors.initials: O
authors.lastname: Verneau
authors.affiliation: School of Earth Sciences, University of Bristol, Life Science Building, Bristol, UK.
authors.forename: Philip C J
authors.initials: PC
authors.lastname: Donoghue
mesh_terms: D000818:Animals; D005075:Biological Evolution; D005580:Fossils; D006790:Host-Parasite Interactions / Q000502:physiology*; D006801:Humans; D007448:Invertebrates / Q000469:parasitology; D010986:Platyhelminths / Q000145:classification / Q000235:genetics / Q000502:physiology*; D013995:Time; D014714:Vertebrates / Q000469:parasitology
keywords: Calibration; Cestoda; Coevolution; Coprolite; Evolutionary history; Fossil record; Molecular clock; Mollusca; Monogenea; Neodermata; Pathology; Platyhelminthes; Platyzoa; Trematoda; Vertebrates