Systematics of Pyrgomorphidae (Orthoptera: Caelifera)

The family Pyrgomorphidae (Orthoptera: Caelifera: Acridomorpha), commonly known as gaudy grasshoppers, is defined by the presence of a groove in the fastigium and internal genitalia structures. It consists of 477 species in 149 genera. They are primarily distributed in the Old World with only 29 species found in Australia and 29 in the New World. Currently the family is divided in two subfamilies, Pyrgomorphinae and Orthacridinae, with a total of 31 tribes and 5 genera incertae sedis. Despite many interesting features of the family, such aposematic coloration, wing reduction, plague potential and its use as human food, there is no phylogenetic hypothesis available for Pyrgomorphidae. Although the most recent phylogenetic analysis based of mitochondrial genome data places as a sister group of the superfamily Acridoidea, the relationships within Pyrgomorphidae are vague and poorly understood, and even there are not synapomorphies that define the two subfamilies. In order to understand the evolution of this family, we reconstruct a phylogeny based on morphological characters, both from external and internal morphology (genitalia). We used 42 ingroup genera representing all the 18 current pyrgomorphine tribes and 10 of the 13 orthacridine tribes. We tested the monophyly of the family and other previously suggested internal groups (subfamilies and tribes) and comment on interesting evolutionary trends such the evolution of chemical defense and its correlation with warning coloration and the evolution of wing reduction. Finally, taking into account the geologically recent appearance of the group (~20 mya); we discussed the peculiar biogeography of the group.