Systematics of Caenodelphax Fennah (Hemiptera: Fulgoroidea: Delphacidae)

Delphacid planthoppers (Hemiptera: Fulgoromorpha: Delphacidae) are of worldwide economic interest as crop pests and vectors of plant diseases. Despite their importance, much of their evolutionary history remains poorly understood and many genera within Delphacidae need revision. Delphacodes Fieber, 1866 once included more than 136 species, including many New World species, but was redescribed with a more limited definition, reducing it to only 10 western Palearctic species. This left the majority of Delphacodes species in need of reassignment to other genera.  

Hamilton (2002) hypothesized that 10 New World Delphacodes species belong to Caenodelphax Fennah, 1965. This project undertook an investigation of Hamilton’s hypothesis by examining a subset of 13 Delphacodes and 4 Caenodelphax species with reference to morphological phylogenetic analyses to determine their evolutionary relationships. Phylogenetic analyses using maximum parsimony did not support Hamilton’s hypothesis, and instead suggested that eight ingroup species belong in a separate, new genus. Caenodelphax is redescribed here as a monotypic taxon; eight species are transferred to the new genus, Flavoclypeus, and two species are synonymized.