Search Results (3)

Archaeognatha is phylogenetically positioned as the basal lineage relative to all extant insect orders and comprises approximately 600 described species. The internal phylogenetic relationships and divergence times within this ancient order have long been a subject of scientific debate. In this study, we assembled 14 mitochondrial genomes from species within the genera Pedetontus and Pedetontinus to clarify the phylogenetic relationship and estimate divergence times within Archaeognatha. Phylogenetic analyses revealed that both Machilidae and Machilinae are paraphyletic; Pedetontinus included in this analysis formed a well-supported monophyletic clade, whereas the sampled Pedetontus species were not recovered as a monophyletic clade. Divergence time estimates indicate that Archaeognatha originated during the Late Carboniferous (301.15 Mya, 95% HPD: 298.88–303.67 Mya), with subsequent diversification spanning from the Mesozoic era to the present. The adaptive radiation of epiphytic bryophytes and potential coevolutionary interactions between plants and insects are proposed to have significantly contributed to the diversification of Archaeognatha. Based on multiple lines of evidence, we propose that the current morphological criteria for species delineation within Pedetontus (Pd.) require revision to better reflect its evolutionary history. In the branch-site model analysis, when Pd. silvestrii—collected from temperate regions—was designated as the foreground branch, two positively selected sites were detected at the 66th position of the Cytb and the 34th position of ATP6. When Pd. hainanensis and Pd. bawanglingensis—collected from tropical regions—were used as the foreground branches, six positively selected sites were identified at the 622nd position of Cytb, the 499th position of ATP6, and the 623rd, 873rd, 1106th, and 1141st positions of COI. Full article

Bristletails (Microcoryphia) represent a relatively understudied group of class Insecta. These wingless hexapods, which retain numerous plesiomorphic structures, remain less well understood compared to most other insect lineages. Through detailed morphological examination of specimens collected from southern China, we describe six new species (Pedetontus (Verhoeffilis) elegans sp. n. from Zhejiang; P. (V.) hezhouensis sp. n., P. (V.) jinxiuensis sp. n., and P. (V.) nanningensis sp. n. from Guangxi; and P. (V.) shenzhenensis sp. n. and P. (V.) xanthospilus sp. n. from Guangdong) of subgenus Verhoeffilis Paclt, 1972. This subgenus is distinguished from other members of the Petrobiinae by several diagnostic features: paired ocelli shoe-shaped (fusiform-shaped) and submedian; two pairs of retractile vesicles on abdominal segments II–V; parameres restricted to coxite IX; penis opening small and apical; male genitalia not exceeding coxite IX; and ovipositor of primary type. The new species can be distinguished from known species and each other by the morphology of the compound eyes, maxilla, labial palps, legs, and genitalia; here, we provide detailed illustrations, tables, and descriptions. Furthermore, we sequence the COX1 gene to construct a phylogenetic tree of Microcoryphia. This contribution increases the total number of reported Pedetontus species in China to seventeen. Full article

Archaeognatha (bristletails) represent an evolutionarily significant but understudied insect group. Notably, the morphological identification method proposed by Mendes for Archaeognatha has certain limitations, which may lead to the underestimation or misidentification of some cryptic species. To address this issue, we employed an integrated strategy that combines morphological and molecular identification methods. Therefore, this study aimed to (1) identify cryptic diversity within Pedetontus silvestrii using mitogenomic data; (2) clarify phylogenetic relationships among Archaeognatha lineages; and (3) estimate divergence times for key taxonomic splits. We analyzed mitochondrial genomes from six P. silvestrii populations (Liaoning, Jilin, and Hebei Provinces) alongside 14 published Archaeognatha genomes. Key findings include the following: (1) Integrative analyses of genetic distances, phylogenetic reconstruction, bPTP-based molecular species delimitation, and divergence time estimation collectively revealed four evolutionarily distinct lineages within P. silvestrii. (2) Machilidae and Machilinae were non-monophyletic, whereas Petrobiellinae showed close affinity to Meinertellidae. (3) Archaeognatha originated ~301.19 Mya (Late Carboniferous); the Machilinae–Petrobiinae split occurred approximately 153.99 Mya (Jurassic). This study underscores the critical importance of mitogenomic analysis in elucidating cryptic biodiversity, while emphasizing the necessity of integrating morphological identification with molecular characterization for comprehensive species delineation in future taxonomic investigations. Full article