Chuanblatta gen. nov. sexually dimorphic cockroaches of Raphidiomimidae (Blattaria) from the Jiulongshan Formation in China

Abstract

Six different families of predatory cockroaches have been reported hitherto for Blattaria. Among which the most distinct was the Raphidiomimidae spreading from the Early Jurassic to the Late Cretaceous. Up to date, seven genera and ten species of raphidiomimids have been documented worldwide, among which four genera with five species from the Middle Jurassic Jiulongshan Formation of Daohugou, China. Herein, we describe Chuanblatta huntianlingensis LIANG, WANG, SHIH et REN gen. et sp. nov. and C. lata LIANG, WANG, SHIH et REN gen. et sp. nov. from the same locality to highlight their sexual dimorphism that males with elongate forewings were statistically distinguished from females with relatively broad and round forewings. Furthermore, males had tergal glands for providing nuptial nutrition and both sexes bore distinctly raptorial forelegs and large subapical teeth and series of lateral and terminal teeth on mandibles, which are autapomorphies within Raphidiomimidae. Together with other 530 similar specimens in our collections, not covered in this study due to lack of preserved sexual organs or forewing length/width ratios, these Chuanblatta LIANG, WANG, SHIH et REN gen. nov. cockroaches provided clear indication of strong dominance among all predatory cockroaches.