Tetralichine trilobites from the Upper Ordovician of Oklahoma and Virginia and phylogenetic systematics of the Tetralichini

Abstract

New material, including a complete exoskeleton, from the Bromide Formation of Oklahoma, allows a complete evaluation ofProbolichasPhleger, 1936 and necessitates a quantitative revision of the lichid tribe Tetralichini Phleger, 1936. A strict consensus tree of nine equally parsimonious trees generated from a branch and bound analysis indicates that the genusProbolichasis monophyletic, and should no longer be restricted as synonymous with, or as a sub-clade ofAmphilichasRaymond, 1905. The genusApatolichasWhittington, 1963 is revised as a synonym ofAmphilichas, and the Tetralichini is defined as clade with three genera:Amphilichas, Probolichas, andLyralichasWeber, 1948.Probolichas kristiaefrom the Bromide Formation andAmphilichas effnensisfrom the Effna Formation of Virginia are new species.