One such delineation named the Euenantiornithes, was defined by Chiappe (2002) as comprising all species closer to "Sinornis" than to "Iberomesornis". Because "Iberomesornis" is often found to be the most primitive or basal enantiornithine, Euenantiornithes may be an extremely inclusive group, made up of all Enantiornithes except for "Iberomesornis" itself. Despite being in accordance with phylogenetic nomenclature, this definition of Euenantiornithes was severely criticized by some researchers, such as Paul Sereno, who called it "a ill-defined clade [...] a good example of a poor choice in a phylogenetic definition".