Evidence from male genitalic morphology on basal phylogenetic splitting events in Mantodea

The Dictyoptera, which include the Mantodea and Blattodea, have highly complicated male genitalia (phallomeres), which are very asymmetrical. While the structural pattern of the male genitalia is hardly comparable between Dictyoptera and any other insects, the degree of similarity found within Dictyoptera is sufficient for proposing discrete topographic homologies. Genitalic morphology is compared between members of the "basal" mantodean genera Mantoida, Chaeteessa, and Metallyticus and the more derived Sphodromantis; in Chaeteessa and Metallyticus only the exoskeleton has been studied, while for Mantoida and Sphodromantis data on the musculature are also available. Some blattodeans (mainly from Blattidae) are additionally considered in order to provide outgroup comparison for Mantodea. The characters of the male genitalia are evaluated phylogenetically, resulting in the relationships Mantoida (Chaeteessa ( Metallyticus, Sphodromantis)). The clade Chaeteessa + Metallyticus + Sphodromantis is supported, for instance, by the reduction of an internal ridge along the left side of the phallomeres and by an expansion of left sclerites to the right in the dorsal wall (also evident from muscle attachments compared between Mantoida and Sphodromantis). The clade Metallyticus + Sphodromantis is supported, for instance, by a membraneous articulation that divides the left sclerotisations into a dorsal and ventral sclerite.