Ascaridia galli (Nematoda: Ascaridiidae) is the most common intestinal roundworm of chickens and other birds with a worldwide distribution. Although A. galli has been extensively studied, knowledge of the genetic variation of this parasite in detail is still insufficient. The present study examined genetic variation in the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene among A. galli isolates (n = 26) from domestic chickens in Hunan Province, China. A portion of the cox1 (pcox1) gene was amplified by polymerase chain reaction separately from adult A. galli individuals and the amplicons were subjected to sequencing from both directions. The length of the sequences of pcox1 is 441 bp. Although the intra-specific sequence variation within A. galli is 0–7.7%, the inter-specific sequence differences among other members of the infraorder Ascaridomorpha were 11.4–18.9%. Phylogenetic analyses based on the maximum likelihood method using the sequences of pcox1 confirmed that all of the Ascaridia isolates were A. galli, and also resolved three distinct clades. Taken together, the findings suggest that A. galli may represent a complex of cryptic species. Our results provide an additional genetic marker for the management of A. galli in chickens and other birds.

The complete mitochondrial genome sequence of Pelodiscus axenaria was determined by shotgun sequencing. The total length of mitogenome is 16,593 bp, and contains 13 protein-coding genes, 22 tRNA genes, 2 ribosome RNA genes, and 1 control region. Most of the genes of P . axenaria were distributed on the H-strand, except for the ND6 subunit gene and eight tRNA genes which were encoded on the L-strand. The phylogenetic tree of P . axenaria and 11 other closely related species was reconstructed. The phylogenetic analyses based on these mitogenomes presented here will be useful for further insights on the evolutionary relationships of Trionychidae.

The complete mitochondrial genome sequence of Bufotes zamdaensis was reported in the present research by shotgun sequencing. The total length of mitogenome is 17,189 bp, and contains 13 protein-coding genes, 22 tRNA genes, two ribosome RNA genes, and one D-loop region. All gene conformations were consistent with the gene arrangement in vertebrates. Most of the genes of B. zamdaensis were distributed on the H-strand, except for the ND6 subunit gene and eight tRNA genes which were encoded on the L-strand. Phylogenetic analysis of B. zamdaensis and 12 other closely amphibian species was reconstructed using Maximum-likelihood methods. The sequences of B. zamdaensis were clustered in genus Bufotes. The phylogenetic analyses based on these mitogenomes presented here will be useful to further insights on the evolutionary relationships of Bufonidae.

The complete mitochondrial genome sequence of Lycodon ruhstrati was determined by shotgun sequencing. The total genome size is 17,168 bp, and contains 13 protein-coding genes, 22 tRNA genes, 2 ribosome RNA genes and 2 control regions (D-loops). Most of the genes of L. ruhstrati were distributed on the H-strand, except for the ND6 subunit gene and eight tRNA genes which were encoded on the L-strand. The phylogenetic tree of L. ruhstrati and 12 other closely related species was reconstructed. The mitogenome sequence presented here will be useful to study the evolutionary relationships and genetic diversity of L. ruhstrati.