Systematics and evolutionary timing of Trigonidiidae (Orthoptera: Grylloidea): insights into pygmy and sword-tail cricket diversification

Trigonidiidae, one of the most species-rich groups within Grylloidea, provides valuable insights into insect evolution and diversification. However, studies on Trigonidiidae have yet to establish a robust phylogenetic framework, primarily due to insufficient taxonomic sampling and limited molecular data. To address these gaps, this study generated extensive molecular datasets, including complete mitochondrial genomes, ribosomal DNA (rDNA), and DNA barcoding data, to reconstruct the phylogenetic relationships of 126 species spanning 37 genera and 2 subfamilies within Trigonidiidae. Our analyses revealed several novel phylogenetic relationships at various taxonomic levels (family, subfamily, and tribe). Furthermore, divergence time estimation suggested that Trigonidiidae originated in the Late Jurassic (approximately 147 Mya) and experienced a period of rapid diversification during the Cretaceous, as supported by molecular clock analysis. The major lineages of Trigonidiidae diverged during the Early Cretaceous Valanginian stage, overlapping with the radiation of angiosperms, suggesting a potential ecological or evolutionary link. By integrating multiple molecular markers, this study establishes the most comprehensive and well-resolved phylogenetic framework for Trigonidiidae to date, providing a robust foundation for future research on the adaptive radiation and evolutionary dynamics of this diverse insect family.