The complete mitochondrial genome of the freshwater crab Chinapotamon maolanense (Decapoda: Brachyura: Potamoidea)

Abstract The complete mitochondrial genome of Chinapotamon maolanense was obtained for the first time. The complete mitochondrial genome of C. maolanense is 17,130 bp in length, including 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 1 control region. In addition, the mitogenome has 18 noncoding regions ranging from 1 to 1553 bp in length.

An adult specimen of C. maolanense was collected from Panzhai Village, Dawn township aquatic animals, Libo County, Qiandongnan Miao and Dong Autonomous Prefectu, Guizhou Province, China in 2017 (N25.234444 , E 108. 029527 ). The sample has been deposited in the Laboratory Specimen Library of Freshwater Crustacean Decapoda & Paragonimus, School of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi, PR China & National Parasite Germplasm Resources Specimen Library of China with a catalogue number of NCUMCP1960. The sample was stored in 95% ethanol prior to extraction at room temperature before sequence analyses. Genomic DNA extraction, sequencing, gene annotation, and phylogenetic analyses were performed according to the method described by Plazzi et al. (2013). The Bayesian Inference (BI) method was performed using MrBayes vers. 3.2 (Ronquist et al. 2012), with best model GTR þ I þ G selected using jModelTest vers. 2.1.7. The maximum-likelihood (ML) method was performed using MEGA 6 (Tamura et al. 2013).
Chinapotamon maolanense (GenBank accession no. MT134100) has a full-length mitochondrial genome of 17,130 bp and shares the same 37 genes (13 protein-coding genes, 22 tRNA genes, and 2 rRNA genes) and 1 control region (CR) as the typical metazoan mitochondrial genome (Yan et al.), with a high A þ T bias (71.7%). The CR of C. maolanense is located in a typical crustacean position (between 12SrRNA and tRNA Ile ), it is 1553 bp in length, and has a higher A þ T bias (76.5%) than does the mitochondrial genome. Among these genes, 23 are located in the H-strand, and 14 are located in the L-strand.
The mitochondrial genome of C. maolanense has 18 noncoding regions and is between 1-1553 bp in length, with the longest noncoding region between 12S rRNA and tRNA Ile which is considered to be the CR; there are nine gene overlap areas, with a total length of 25 bp, and those areas are between 1 and 7 bp in length, with the longest gene overlap area between ND4 and ND4L.
The mitochondrial genome of C. maolanense possesses two rRNA genes, 16S rRNA and 12S rRNA, which are located in the same L chain as other Brachyura mitochondrial genomes. The length of the 16S rRNA and 12S rRNA genes is 1318 bp and 824 bp, respectively; 16S rRNA is between tRNA Leu(CUN) and tRNA Val , while 12S rRNA is between tRNA Gln and the CR.
The phylogenetic position of C.maolanense in mitogenome relative to other freshwater crabs mitogenomes is determined by applying the BI and ML methods on 13 PCGs (Figure 1). Our results indicate that as one of the freshwater crabs, C. maolanense is the sister group with Huananpotamon lichuanense and Sinolapotamon patellifer. This result is consistent with morphological classification and other molecular analyses (Dai 1999).

Disclosure statement
No potential conflict of interest was reported by the author(s).

Data availability statement
The data that support the findings of this study are openly available in GenBank of NCBI at https://www.ncbi.nlm.nih.gov, reference number MT134100.