Early elytrification of forewings of Palaeozoic cockroachoids: revision of the Carboniferous–Permian family Poroblattinidae (Insecta, Dictyoptera) based on new finds from Morocco

Abstract

Abstract Recently discovered numerous and partially articulated poroblattinid cockroaches (Insecta, Poroblattinidae) from the Upper Pennsylvanian Souss basin of Morocco provide new insights into intraspecies wing venation variation. Based on them, a complete revision of the family Poroblattinidae is provided here. As a result, only one family (Poroblattinidae Handlirsch) out of two original families remains; only one genus ( Poroblattina Scudder) out of 12 genera and only three out of 48 species remain; these are Poroblattina germari (Giebel), P . rotundata (Scudder) and P . duffieuxi (Pruvost). Poroblattinids range from the Middle Pennsylvanian to the lower Permian. Previous records of Mesozoic poroblattinids were erroneously based on the misinterpretation of venation patterns. The Moroccan poroblattinid assemblage consists of P . germari (Giebel) and P . rotundata (Scudder), which are also known from several localities in the Upper Pennsylvanian and lower Permian of Europe and North America. Poroblattinids co‐occur in the upper Kasimovian to lower Gzhelian Souss basin with mesophilous and xerophilous plants as well with xeromorphic mylacrid dictyopterans. Late Pennsylvanian (early Stephanian) poroblattinids show an advanced sclerotization of the forewings compared with the tegmina of contemporaneous phyloblattids and spiloblattinids. Causes and consequences of this elytrification are discussed in comparison with the elytra of the oldest known Coleoptera and Protelytroptera.