Complete mitochondrial genome of : molecular structure and phylogenetic analysis.

spp. (Nematoda: Strongylida: Cyathostominae) are the common and important parasitic nematodes found in horses and donkeys worldwide. In this study, the complete mitochondrial genome of Looss 1900, a representative member of this genus from the donkey in Southwest China was determined using the next-generation DNA sequencing technology. The genome was 13,851 bp in size and consisted of 36 genes including 12 protein-coding genes (6, 1-3, , 1-6 and 4L), 22 transfer RNA genes and two ribosomal RNA genes (L and S), as well as two non-coding regions. Phylogenetic analysis showed that and Boulenger 1917 were closely related, and then both grouped with other congeneric species and formed a monophyletic relationship with either species of , , , or , demonstrating their phylogenetic stability within Cyathostominae. These cumulative mitochondrial DNA data provide novel and useful genetic markers for molecular diagnostic, systematic and evolutionary biological studies of Cyathostominae nematodes.