Comparative Mitochondrial Genomic and Phylogenetic Study of Eight Species of the Family Lonchodidae (Phasmatodea: Euphasmatodea)

<b>Background:</b> Lonchodidae is the largest family within the order Phasmatodea, and although many studies have been conducted on this family, the monophyly of the family has not been established. <b>Methods:</b> Eight mitogenomes from Lonchodidae, including the first complete mitogenomes of four genera, were sequenced and annotated to explore their features and phylogenetic relationships. <b>Results:</b> The total length ranged from 15,942-18,021 bp, and the mitogenome consisted of 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes, and a control region (CR). <i>atp8</i> had the highest A + T content in Lonchodidae, except for <i>Neohirasea stephanus</i> and <i>Asceles clavatus</i>, in which the highest A + T contents were detected in <i>nad6</i>. The phylogenetic trees were reconstructed via Bayesian inference (BI) and maximum likelihood (ML) based on the PCG123 and PCG12 datasets. As the phylogenetic trees show, Necrosciinae is recognized as monophyletic, but the monophyly of Lonchodinae has not been supported. Gene deletion and rearrangement have occurred mainly in Lonchodidae and Aschiphasmatidae. The most common reason for gene rearrangements was tandem duplication random loss (TDRL), but <i>trnI</i> of <i>Stheneboea repudiosa</i> inverted into the CR. In addition, genes within the same family or genus share related sequences and conserved gene blocks. <b>Conclusions:</b> we expanded the mitochondrial genomic data for this family, thereby establishing a foundational dataset for future studies.