Trigonidiini Saussure, 1874

Hegg, Danilo, 2024, Small crickets of New Zealand (Orthoptera: Grylloidea: Trigonidiidae and Mogoplistidae), with the description of two new genera and species, European Journal of Taxonomy 955 (1), pp. 1-87 : 57

Tribe Trigonidiini Saussure, 1874

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) .

Figures

Fig. 31. Gene tree for Trigonidium Rambur, 1838 using Maximum Likelihood analysis of ~700 bp of mtDNA (COI) from 23 specimens and 1000 bootstrap replications. The tree with the highest log likelihood (-3571.04) is shown. Numbers next to the branches indicate the percentage of trees in which the associated taxa are clustered together. The tree is drawn to scale, with branch lengths measured in the number of substitutions per site. Specimens in blue were collected as part of this study; the remaining 15 sequences were obtained from the GenBank (Benson et al. 2013) and BOLD (Ratnasingham & Hebert 2007) databases. Detailed information for each specimen included in this analysis can be found in Supp. file 1: Table S11.