Complete Mitochondrial Genome of Sp. (Nematoda: Ascarididae) from Night Herons in China.

species are zooparasitic anisakid nematodes and occur in gastrointestinal tracts of vertebrate/invertebrate animals, including humans, causing gastrointestinal pain, diarrhea, and increasingly severe vomiting. Although the complete mitochondrial (mt) genome (mitogenome) of sp. isolated from night herons in Beijing has been reported, the detailed information about this mt sequence is still puzzling. In the present study, we described the detailed characteristics across the complete mt DNA of sp., which includes 36 genes consisting of 12 protein genes, 22 transfer RNAs (tRNAs), 2 ribosomal RNAs (rRNAs), and 2 noncoding regions (NCRs), and all genes have the same orientation of transcription. The AT content in the complete mitogenome of sp. was 72.2%, and it was the least value (66.7%) in the 1 gene but was the highest rate (84.1%) in NCRs. The highest nucleotide diversity (Pi) among the genus was 4 (0.190) and the least was 1 (0.125), which indicates that 4 might have the potential ability as useful markers to detect cryptic species in the genus or subspecies. Based on the maximum likelihood (ML) and Bayesian inference (BI) computational algorithms within subfamilies Ascaridoidea and Heterakoidea, the results supported that sp. was a new species and the family Ascaridiidae was paraphyletic. The complete mitogenome sequence of sp. supported a clear recognition of species and provided the potential existence of cryptic species in the genus . Our findings would better contribute to the surveillance, molecular epidemiology, and control of .