130 years from discovery to description: micro-CT scanning applied to construct the integrative taxonomy of a forgotten moth from Southern Africa (Lepidoptera: Geometridae)

Abstract

X-ray micro-computed tomography (micro-CT) of dried and pinned museum specimens combined with advanced image processing can provide a useful, novel and non-destructive tool for integrative insect taxonomy. This paper demonstrates how micro-CT can be applied to provide unambiguous illustrations of diagnostic morphological characters for new taxa description and to understand how micro-CT imaging may complement other imaging techniques. Following micro-CT scanning, a semi-automatic segmentation and volume rendering protocol was used to portray the wing venation and diagnostic structures and ornamentation of male genitalia from multiple angles. Using micro-CT images, we provide the description of a conspicuous geometrid moth from southern Africa (Lepidoptera: Geometridae), which has been present in collections since 1894, but left without an available name. Using a multigenetic dataset comprising 273 terminal taxa from the superfamily Geometroidea, we constructed a molecular phylogeny to place our study species to an isolated lineage in Geometridae: Larentiinae, tribe Xanthorhoini sensu lato. We describe it as Chloecolora vergetaria new genus, new species Englund & Staude, and provide diverse ecological information on its distribution, habitat, host plant, adult and immature stages, and parasites. We found micro-CT imaging particularly useful in two- and three-dimensional imaging of wings, providing detailed information for instance on non-tubular folds that may be difficult to distinguish using other techniques.