Characterization of the Mitochondrial Genome of (Astacidea: Cambaridae) and Its Phylogenetic Implications.

Background: is an endangered freshwater crayfish in China, belonging to the genus Cambaroides, that can act as a complementary host for paragonimus. The objective of this study was to examine the complete mitochondrial genome characteristics and their evolutionary relationships within the Astacidea.

Methods: The analysis of gene rearrangements and evolutionary relationships was conducted through the sequencing of the mitochondrial genome of .

Results: mitochondrial genome length was 15,572, comprising thirteen PCGs, two rRNAs, 22 tRNAs, and one d-loop region of . The mitochondrial genome of exhibits an A + T content of 69.61% and a G + C content of 30.39%. Among the thirteen PCGs, cytb, nad3, and nad6 have a start codon of ATT, while the other ten PCGs have ATC, ATA, and ATG start codons. All 22 tRNA genes displayed a typical cloverleaf secondary structure. Gene rearrangement analysis showed that seven gene arrangements were identified based on PCGs in the infraorder Astacidea, with type I being the most common.

Conclusions: The relationship between the American Cambaridae is closer to Astacidae than the Asian Cambaridae. The present study provides a theoretical basis for further discussions of developmental relationships in the infraorder Astacidea.