Revision of the New Zealand cave wētā genus Isoplectron Hutton (Orthoptera: Rhaphidophoridae), with synonymy of Petrotettix Richards and Setascutum Richards, and the description of a new genus

Abstract

The New Zealand cave wētā genus Isoplectron was first described by Hutton (1896) and included two species, Isoplectron armatum and I. calcaratum. Two more species, I. cochleatum and I. aciculatum, were described by Karny in 1935 and in 1937, respectively. The species I. cochleatum was later moved to the genus Pharmacus Pictet & de Saussure, 1893. Here we clarify the status and appearance of all known species of Isoplectron, and of other closely related cave wētā. Based on morphology and mtDNA sequences we determine that the genera Petrotettix Richards, 1972 and Setascutum Richards, 1972, belong in Isoplectron, and are thus synonymised with the latter. We also infer that Isoplectron aciculatum Karny, 1937 does not hold species rank, and that it should be considered a subspecies of Isoplectron armatum instead. The male of Isoplectron pallidum (Richards, 1972) comb. nov. and the female of Isoplectron armatum aciculatum Karny, 1937 are described here for the first time. Using molecular data, we also establish that two new species that are morphologically similar to Isoplectron are in fact more closely related to Pharmacus. These species are assigned to a new genus, Praecantrix gen. nov. We describe seven new species and two new subspecies of New Zealand rhaphidophorids belonging to the genera Isoplectron Hutton, 1896 and Praecantrix: Isoplectron bicolor sp. nov., I. maculatum sp. nov., I. virgatum sp. nov., I. ferratum sp. nov., I. parallelum sp. nov., Praecantrix silvatica silvatica gen., sp. et subsp. nov., P. silvatica lutea gen., sp. et subsp. nov. and P. saxicola gen. et sp. nov. Species demoted to subspecies rank: Isoplectron aciculatum Karny, 1937 becomes Isoplectron armatum aciculatum Karny, 1937. New combinations: Setascutum pallidum Richards, 1972 becomes Isoplectron pallidum (Richards, 1972) comb. nov.; Petrotettix serratus Richards, 1972 becomes Isoplectron serratum (Richards, 1972) comb. nov. New synonyms: Isoplectron calcaratum Hutton, 1896 = Isoplectron armatum Hutton, 1896 syn. nov.; Setascutum ohauensis Richards, 1972 = Isoplectron armatum Hutton, 1896 syn. nov.; Petrotettix spinosus Richards, 1972 = Isoplectron serratum (Richards, 1972) syn. nov.; Petrotettix cupolaensis Richards, 1972 = Isoplectron serratum (Richards, 1972) syn. nov.; Petrotettix nigripes Richards, 1972 = Isoplectron serratum (Richards, 1972) syn. nov.