Status of the New Zealand cave weta (Rhaphidophoridae) genera Pachyrhamma, Gymnoplectron and Turbottoplectron

Abstract

The New Zealand Rhaphidophoridae Walker, 1869 comprise 18 endemic genera (including 8 that are monotypic). Although there are many new species to be described, rationalisation at the genus level is also required due to inconsistencies in their current systematics. Even the largest and best known taxa, including those that occupy cave systems and are the most frequently encountered by people, require taxonomic revision. These cave weta include species assigned to three poorly differentiated genera, Pachyrhamma Brunner v. Wattenwyl, 1888, Gymnoplectron Hutton, 1897 and Turbottoplectron Salmon, 1948, that are best known from North Island New Zealand. We used mitochondrial DNA sequence data to examine their relationships using representatives of each genus. The results indicate that a single genus Pachyrhamma would be appropriate for all, as Gymnoplectron and Turbottoplectron nest phylogenetically within it. There are insufficient morphological, spatial or ecological reasons to justify retention of all three. However, we also note that species level diversity does not correlate with genetic or spatial diversity; some species are genetically well partitioned and widespread while others have narrow ranges in single cave systems and are closely related to one another.