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

Abstract

Lipotactinae is an elusive monophyletic subfamily of katydids (Orthoptera: Tettigoniidae) unique to Asia and comprising two genera – Lipotactes and Mortoniellus. 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. New Lipotactes specimens collected from Borneo – Belait and Kuala Belalong in Brunei and Sandakan in Sabah – were initially identified as Lipotactes alienus and/or Lipotactes virescens based 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 of L. virescens from 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 from L. virescens and that the populations from Kuala Belalong, Belait, and Sandakan represent different ethospecies. Here, we describe the species from Sandakan as Lipotactes kabili sp. 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.

http://zoobank.org/urn:lsid:zoobank.org:pub:A81579A3-CD0A-453C-BE03-236A21544031

http://zoobank.org/urn:lsid:zoobank.org:act:B89DB3B2-4913-4A6D-9D8D-91AFC5EEDDF8

Key words:

• Brunei Darussalam
• ethospecies
• new species
• Sabah
• Southeast Asia
• taxonomy

Acknowledgements

The authors thank Fernando Montealegre-Zapata for providing an Echo Meter Touch 1 unit for acoustic recording and for providing feedback to the manuscript prior to submission; Huiqing Yeo (in Brunei Darussalam), Siew Tin Toh (in Bukit Larut and Sandakan), Momin Binti, John Lee Yukang, and Saudi Bintang (in Sandakan) for field assistance. The permissions for collecting specimens were granted by the Forestry Department, Ministry of Primary Resources and Tourism, Brunei Darussalam (JPH/PDK/01 Pt 2) and the Sabah Biodiversity Centre (JKM/MBS.1000-2/3 JLD.3 (99)) (for Sandakan).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Associate Editor: Dimitar Dimitrov

Additional information

Funding

The work of MKT was supported by the Orthoptera Species File Grant 2019 under the taxonomic research project titled ‘Contribution to the species diversity and acoustic data on Orthoptera from Sandakan (Borneo, East Malaysia, Sabah)’; and Percy Sladen Memorial Fund (The Linnean Society of London) under the project titled ‘Advancing biodiversity informatics of Orthoptera from Brunei Darussalam’. The bioacoustics component was supported by the Wildlife Acoustics Scientific Product Grant 2019 under the project titled ‘Discovery of Ultrasonic Singing Katydids in Southeast Asia’.