Taxonomic treatment of some Hawaiian Psyllidae

Abstract

A taxonomic treatment of Hawaiian psyllids belonging to the genera Cerotrioza, Crawforda, Hemischizocranium, Kuwayama, Megatrioza, Swezeyana and Trioza is presented. Descriptions and keys to the adults and immatures of the known species, Cerotrioza bivittata Crawford, Crawforda triopsyllina Caldwell, Hemischizocranium aloha (Caldwell), Hemischizocranium bessi Tuthill, Swezeyana elongagena Caldwell, Swezeyana reticulata Caldwell and Trioza unigua (Caldwell); and to the new species Cerotrioza kauaiensis n. sp., Cerotrioza molokaiensis n. sp., Cerotrioza lanaiensis n. sp., Cerotrioza hawaiiensis n. sp., Kuwayama ventralis n. sp., Kuwayama oahuensis n. sp., Kuwayama lanaiensis n. sp., Megatrioza zanthoxyli n. sp. and Swezeyana oahuensis n. sp. are given. The species of the Hawaiian psyllids are hypothesized to have speciated allopatrically. The founder principle is invoked to provide a model which may explain the speciation of psyllids on islands. Trioza has been hypothesized to be the ancestral group for the Hawaiian Psyllidae because its host, Metrosideros was most likely the first of the psyllid hosts to colonize the Hawaiian Islands, and because Trioza was widespread throughout the world and Pacific region. Based on morphological similarity, Trioza hawaiiensis Crawford and Trioza sp. A are allied to Crawforda; Trioza ohiacola Crawford, Trioza lehua Crawford and Trioza pullata Crawford are allied to Kuwayama and Swezeyana; and Trioza sp. B, Trioza sp. C and Trioza sp. 0 appear to be related to Cerotrioza, Hemischizocranium, Megatrioza and Trioza unigua. Cladistic analysis was not possible due to the absence of synapomorphic characters at the species and generic levels.