Ultrasonic bioacoustics and stridulum morphology reveal cryptic species among Lipotactes big-eyed katydids (Orthoptera: Tettigoniidae: Lipotactinae) from Borneo

Lipotactinae is an elusive monophyletic subfamily of katydids (Orthoptera: Tettigoniidae) unique to Asia and comprising two genera -LipotactesandMortoniellus. Nearly nothing is known beyond their original descriptions. The stridulum morphology is rarely examined and described in taxonomy and their acoustics are only known for six species, none of which is from Borneo. NewLipotactesspecimens collected from Borneo - Belait and Kuala Belalong in Brunei and Sandakan in Sabah - were initially identified asLipotactes alienusand/orLipotactes virescensbased on traditional morphological characters. However, the structures of male calling songs of individuals from Kuala Belalong and Sandakan were profoundly different from each other and from the known songs ofL. virescensfrom Thailand and Peninsular Malaysia. This led us to examine the morphology of the Bornean specimens more closely. By integrating call structures, stridulum morphology, and traditional morphology, we establish that the specimens from Borneo are different fromL. virescensand that the populations from Kuala Belalong, Belait, and Sandakan represent different ethospecies. Here, we describe the species from Sandakan asLipotactes kabilisp. nov. We also demonstrate that both stridulum morphology and call structures can be useful in separating Lipotactinae species because inter-specific differences are larger than intra-specific differences.