Toward a Natural Classification of Tritomini: Are There Hidden Tribes within the Genus Tritoma Fabricius (Coleoptera: Erotylidae)?

Abstract

A preliminary evaluation of world genera based on novel characters revealed a need for nomenclatural changes within North American Tritoma Fabricius (Erotylidae: Tritomini). The previously Asian subgenus “Cyrtotriplax” (Rotitma) Chûjô, 1969, is here given full generic status. Species presently in this subgenus are given new combinations: Rotitma circumcinctus (Lewis, 1887), Rotitma discalis (Lewis, 1887), Rotitma pallidiventris (Lewis, 1887), Rotitma rufipennis (Lewis, 1887), and Rotitma sarawakensis Chûjô, 1974. Two historically controversial species of Tritoma in North America, Tritoma pulchra Say and Tritoma sanguinipennis (Say), are transferred to different genera becoming Aporotritoma pulchra (Say) and Rotitma sanguinipennis (Say), new combinations. Interestingly, the classification of Chûjô and Chûjô (1990) placed Aporotritoma Arrow, 1925 in a “Triplacini” and Rotitma in a “Tritomini” (= Cyrtotriplacini). This division is not reflected in recent phylogenetic works which present the Tritomini as doubtfully having monophyletic status. Preliminary evaluation of new characters, along with our diagnoses of A. pulchra and R. sanguinipennis, suggest a ground plan hypothesis for the tribes “Tritomini” and “Triplacini” within the current Erotylinae. A discussion of characters for use in a larger phylogenetic study of the current Tritomini is presented.