Taxonomic revision and phylogenetic analysis of the enigmatic scorpionfly genus Leptopanorpa MacLachlan (Mecoptera: Panorpidae)

The representatives of the enigmatic genus Leptopanorpa MacLachlan are characterized by exaggeratedly elongated male abdomens and are likely endemic to Java and Sumatra, Indonesia. Here, we present a taxonomical revision of 14 species of Leptopanorpa, including two new species: Leptopanorpa linyejiei sp. n. from West Java and Leptopanorpa majapahita sp. n. from East Java. A key to species of Leptopanorpa is provided. Leptopanorpa sieboldi MacLachlan is treated as a junior synonym of Leptopanorpa charpentieri (Burmeister), and Leptopanorpa pi decorata Lieftinck is synonymized with Leptopanorpa pi (van der Weele). Leptopanorpa peterseni Lieftinck is reported from Bali for the first time. In order to unravel the phylogeny of Leptopanorpa and other groups with elongated male abdomens, maximum parsimony and Bayesian inference analyses were performed based on 61 morphological characters and partial sequences of one nuclear gene (28S ribosomal RNA) and two mitochondrial genes (cytochrome c oxidase subunits I and II). Thirty-three species in Panorpoidea were selected as in-group taxa and two species in Choristidae as out-group taxa. The results highly support a monophyletic Leptopanorpa, which nests within a paraphyletic Neopanorpa van der Weele. Both parsimonious and Bayesian results suggest that Leptopanorpa can be divided into four subclades. We elucidated the evolutionary history of Leptopanorpa with regard to the paleogeological events of Sundaland and corroborated the multiple origins of elongated male abdomens in Panorpoidea. We also hypothesized that the ventral hook on the male abdominal sternum VI of L. linyejiei sp. n. is very likely used to control the female's abdomen during copulation.