Application of DNA barcoding in identification of the genus Loxoblemmus in China

The genus Loxoblemmus Saussure, 1877 comprises 61 described species worldwide, with 18 species recorded in China. Previous taxonomic studies have primarily relied on facial morphological characters for species identification, despite notable intraspecific variation reported in these traits.

In this study, we integrated morphological examination (27 samples) with molecular analysis (COI gene sequences from the same 27 samples and additional sequences from NCBI) to conduct a preliminary reassessment of species identification in Chinese Loxoblemmus crickets.

Molecular delimitation based on COI gene sequences grouped the 27 samples into 7~8 putative species, demonstrating incongruence with the 9 morphospecies identified. Cryptic species might exist within the samples of L. taicoun, or they may be undergoing speciation due to geographic isolation. Moreover, males of L. appendicularis and L. intermedius exhibit pronounced head polymorphism, leading to overlapping and ambiguous morphological identifications between these two species. The high degree of male head polymorphism in L. doenitzi had resulted in some individuals being identified as L. detectus or L. haani. It is proposed that L. detectus and L. haani should be removed from the Chinese Loxoblemmus checklist.

In summary, this study reveals the limitations of traditional morphological taxonomy in the genus Loxoblemmus, confirms the feasibility of DNA barcoding for species identification in this genus, and proposes practical solutions for future taxonomic revisions.