The unique ecological environment of the Qinghai-Xizang Plateau has a significant impact on the genetic differentiation of parasitic organisms. However, the information on the mitochondrial genome of ectoparasites on goats in this region is extremely limited. Flea samples were collected from the body surface of grazing goats and the genome was annotated using MITOS2. A phylogenetic tree was constructed using the maximum likelihood method, and a comparative analysis was conducted with known species of the flea family. A total of two complete mitochondrial genome sequences (G2 and G3) were obtained, with lengths of 16,238 bp and 16,274 bp, respectively. They contain 13 protein-coding genes, 20 tRNA genes and 2 rRNA gene fragments. The base composition shows a significant A+T preference (G2: 79.37%; G3: 79.41%). The 13 protein-coding genes use 5 types of start codons (ATG, ATA, ATT, ATC, GTG) and 2 types of stop codons (TAA, TAG). The phylogenetic analysis shows that G2 and G3 are supported by 100% bootstrap support to form an independent branch, which is located within the flea family but is significantly separated from known flea species. The G2 and G3 samples are on independent branches on the phylogenetic tree and have significant genetic distances from other species. The genomic length and base composition also differ from those of reported species. Based on molecular evidence, these two samples may represent a new undescribed species of the flea family, which awaits further morphological verification. This study reports the first mitochondrial genome of ectoparasites on the body surface of goats in the Qinghai-Xizang Plateau region, providing new data for the phylogeny and species diversity of the flea family.

To Cite This Article: Ni M, Cidan Z, Chang P, Tian M, Li X, Tang W and Wu Q, 2026. Characterization of the complete mitochondrial genomes of two Pulex sp. samples (Siphonaptera: Pulicidae) from the Qinghai-Xizang Plateau. Pak Vet J, 46(9): 2319-2324. http://dx.doi.org/10.29261/pakvetj/2026.215