Les Plourdosteidae fam. nov. (Placodermi, Arthrodira)et leurs relations phylétiques au sein des Brachythoraci

The study of Plourdosteus canadensis (Brachythoraci, Placodermi) from the Escuminac Formation (Frasnian) has led to the creaction of a new family: the Plourdosteidae. It is proposed that Plourdosteus mironovi be considered as a synonym of Plourdosteus trautscholdi, found in the Baltic region of the USSR. The characteristics that support the monophyly of the Plourdosteidae are listed and are represented on a phylogenetic diagram. The Dunkleosteidae sup. fam. nov., the Plourdosteidae fam. nov., and the type species Plourdosteus canadensis are defined. The different species of Plourdosteus are also listed.