Ancient Grasshoppers: A revision of the genus Bullacris (Orthoptera: Pneumoridae)

Abstract

The genus Bullacris in the family Pneumoridae was most recently revised by Dirsh in 1965 based on morphological comparisons between species. However, since that time, new information about the genus and the family has come to light, necessitating a revision of the genus. In addition, the species B. boschimana was originally described based on a single female specimen. Here we present and describe the male of the species for the first time. The aim of this study was to update the current species descriptions by including additional specimens and incorporating additional methods for a more comprehensive comparison. Analyses consisted of morphometric measurements from high-quality images of type specimens, existing South African museum specimens, as well as personally collected specimens. Acoustic signals are also presented and compared between species. In addition, phylogenetic analyses were conducted on the barcoding mitochondrial gene COI and two nuclear genes, namely ITS and 18S. Results show that according to morphological, acoustic and genetic data, B. discolor and B. serrata as well as B. intermedia and B. membracioides share notable similarities. Bullacris discolor and B. serrata share similar phenotypic traits, in which B. discolor can either appear uniform in colour or have a speckled variation that is very similar in appearance to B. serrata. Bullacris intermedia and B. membracioides have a 5% mitochondrial DNA pairwise distance, suggesting that they may have not be fully diverged; however, morphological analysis shows that these species are morphologically distinguishable. It is suggested that these species may have undergone spatial separation at one point; however, further investigation is required. Additional sampling across a wider geographic range is essential to clarify the relationships between B. discolor and B. serrata, as well as between B. intermedia and B. membracioides.