Characterization of the complete mitochondrial genome of Yu & Wu, 1989 (Acanthocephala, Illiosentidae).

The mitogenome of is 13,864 bp in length and has the circular structure typical of metazoans. It contains 36 genes: 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs) and 12 protein-encoding genes (PCGs). All genes are transcribed from the same strand. Thirteen overlapping regions were found in the mitochondrial genome. The overall A+T content of is 68.3% versus 31.7% of G+C content (A = 27.8%, T = 40.5%, C = 9.0%, G = 22.7%). (Illiosentidae) and (Rhadinorhynchidae) form a sister clade, showing the relatively close relationship between the Illiosentidae and the Rhadinorhynchidae. The mitochondrial gene arrangements of acanthocephalan species are relatively conserved, with only a few translocations of tRNAs (trnS1, trnS2, trnV, and trnK) detected. An identical gene order was found both in a sister clade ( and ) and across different classes ( (Palaeacanthocephala), (Eoacanthocephala) and (Archiacanthocephala), and (Palaeacanthocephala)). More studies and more sequences of acanthocephalan species are needed to gain a clear understanding of the phylogenetic relationships.