Phalagnostus

Phalagnostus nudus, the type species, was originally described as a species of Battus by Beyrich in 1845, but that name had already been used for a butterfly, and the trilobite genus was also deemed polyphyletic. Due to the high level of effacement, establishing the relationship of Phalagnostus to other Agnostoidea is difficult. The Treatise lists Phalagnostus as family unknown. Species previously assigned to Phalagnostus • P. bituberculata = Toragnostus bituberculatus == Distribution ==

• P. nudus is known from the Middle Cambrian of the Czech Republic (Eccaparadoxides pusillus-zone, Jince Formation, Týřovice and Skryje-Luh, Bohemia). • P. cuneatus was found in the Middle Cambrian of the Russian Federation (Mayan, Kulyumbe River, limestone, Samodi Formation). • P. rasettii and P. shergoldi have been described from the Upper Cambrian of Canada (Marjuman and Steptoean stages, Rabbitkettle Formation, southern Mackenzie Mountains).{{cite book|last= Pratt|first= B.R.|year= 1992|title= Trilobites of the Marjuman and Steptoean stages (Upper Cambrian), Rabbitkettle Formation, southern Mackenzie Mountains, northwest Canada == Description ==

This agnostoid is strongly effaced. The cephalon lacks a border furrow. The glabella and small basal lobes are weakly defined. The rhachis is circular to ovate, clearly defined by deep axial furrows. An elongate axial node may be discerned. The pygidium has a narrow border defined by a furrow. ==References==