Bioacoustics of Trigonidiini

Remarks Trigonidiinae in the Australian region include a number of genera and subgenera that have been giving taxonomists headaches for decades. To start with, the genus Trigonidium was designated with type species Trigonidium cicindeloides from Spain , Europe. The subgenus Trigonidium ( Trigonidium ) was later proposed by Gorochov (1987) . At present, it is doubtful whether all Australian species assigned to Trigonidium actually belong in Trigonidium sensu stricto at all ( Tan et al. 2019 ). Several closely related genera and subgenera were designated based on the presence or absence of auditory tympana on the anterior tibiae and of a stridulatory apparatus in males ( Otte & Alexander 1983 ). Examples are the subgenera Trigonidium ( Metioche ) , Trigonidium ( Balamara ) Otte & Alexander, 1983 , Trigonidium ( Parametioche ) Otte & Alexander, 1983 , and the genus Trigonidomorpha . Because acoustic communication has been lost several times independently in crickets, some of these genera are likely to be polyphyletic ( Otte & Alexander 1983: 197 ; Chintauan-Marquier et al. 2016 ; Rentz & Su 2019: 316 ; Tan et al. 2019 ). To complicate things, different morphs with or without auditory tympana can appear in the same species ( Ingrisch 1977 ; Rentz & Su 2019 ). It is outside of the scope of this work to resolve the wider systematics of Trigonidiinae in the Australian region. Based on the strong similarities between Trigonidium ( Trigonidium ) maoricum and Trigonidium ( Trigonidium ) cicindeloides and on the analysis of molecular data ( Fig. 31 ), I am confident that T. maoricum belongs to the genus Trigonidium s. str. The genus Trigonidomorpha is synonymised here with Trigonidium ( Trigonidium ) .