Hoplolichoides, Allolichas, Autoloxolichas and Akantharges, and the classification of lichid trilobites

Hoplolichoides PHLEGER, 1936 and Autoloxolichas PHLEGER, 1936 are revised based on redescription of their type species, H. conicotuberculatus (NIESZKOWSKI, 1859) and A. sanctamathiae (SCHMIDT, 1885) respectively. Hoplolichoides is considered to be most closely related to Hoplolichas DAMES, 1877, and both are included in a revised Homolichinae. Autoloxolichas is restricted to its type species, and other species previously assigned to the genus are placed in Allolichas KRUEGER, 1992, the concept of which is expanded. Autoloxolichas and Allolichas are included together with three other genera and subgenera in the Subfamily Platylichinae, previously considered to be a junior synonym of Homolichinae. The hypostomal morphology previously regarded as important in uniting homolichine and platylichine genera is now regarded as primitive for the Lichidae. Metopolichas GÜRICH, 1901, previously included tentatively in the Homolichinae on the basis of its hypostomal morphology, is reassigned tentatively to the Lichinae. The trochurine ‘Acanthopyge’ erbeni MEISCHNER, 1965, from the Givetian of Germany, is assigned to Akantharges PHLEGER, 1936, permitting clarification of the pygidial morphology of the genus. Akantharges and Ceratarges GÜRICH, 1901 are unique amongst lichids in having a curved, transverse ridge on the posterolateral cranidial lobe, suggesting that these genera may have been derived from a common ancestor.