Complete mitochondrial genome of sculptured slipper lobster Parribacus antarcticus (Lund, 1793)

Abstract We first determined and characterized the complete mitochondrial genome of Parribacus antarcticus. It is 15,806 bp long and consists of 22 tRNA, 2 rRNA, 13 protein-coding genes (PCGs), and 1 control region. The nucleotide composition is significantly biased with AT contents of 69.3%. Five PCGs used an unusual initiation codon, and nine PCGs were terminated with an incomplete or abnormal stop codon. Three microsatellites were identified and located in the ND4 gene and D-loop region. Phylogenetic tree showed that P. antarcticus was first clustered with Ibacus ciliatus and Ibacus alticrenatus, which is consistent with the expected phylogenetic relationship.

Parribacus antarcticus, commonly known as sculptured slipper lobster or sculptured mitten lobsters, is an edible economic species in the family Scyllaridae, Achelata, which is distributed from Florida to north-east Brazil in the Atlantic and from the east and south-east Africa to Hawaii and Polynesia in the Indo-West Pacific region (Palero et al. 2014). It mainly inhabits coral reefs or deep-sea reefs and shelters solitarily (Sharp et al. 2007). From the mid-19th century, several studies have been concentrated on the biology of P. antarcticus, including reproduction (Matthews 1954a(Matthews , 1954b, larval development (Ikeda et al. 2011;Palero et al. 2014), ecological observation (Sharp et al. 2007) and new distribution (Wahyudin et al. 2017;Freitas and Wirtz 2018).
The samples were obtained from Huanqiu wharf of Wenchang, Hainan province, China (19 33 0 51.12 00 N, 110 49 0 27.98 00 E), and stored in the marine crustacean specimen room in Qionghai research base of Hainan Academy of Ocean and Fisheries Sciences for reference, Muscle samples of P. antarcticus were preserved in absolute ethanol for total DNA extraction.
The complete mitogenome of P. antarcticus is 15,806 bp in length (GenBank Accession No. MK783264). The base content was 34.5% A, 12.1% G, 34.8% T, and 18.6% C. The 69.3% of (A þ T) showed great preference to AT. The mitogenome sequence consists of 22 tRNA genes, 2 rRNA genes, 13 protein-coding genes (PCGs), and 1 control region (D-loop). Four PCGs (ND1, ND4, ND4L, and ND5), eight tRNA genes and two rRNA genes were located on the light strand, the others were encoded by the heavy strand.
The 22 tRNA genes in mitogenome of P. antarcticus vary in size from 63 to 72 bp. There are two types of tRNA-Leu identified with the codons TAA and TAG, which always were used as stop codons. The 12S rRNA is 863 bp and located between tRNA-Val and D-loop, and the 16S rRNA is 1322 bp, located between tRNA-Val and tRNA-Leu. Except for eight PCGs using the normal ATN as the start codon, the others use an unusual initiation codon (ND1 and ND4L use TTA; COX1 uses ACG; ND4 uses CAC; ND5 uses CTA). Simultaneously, 9 PCGs were terminated with an incomplete or unusual codon in addition to 4 PCGs genes using the normal stop codon TAA. Among the 9 PCGs, COX1, ND2, and ND3 use a single T; ND4 uses AT; COX2 uses TC; CYTB uses TG; ND1 and ND5 use CAC; ND4L uses CAT. The control region is 849 bp, located between 12S rRNA and tRNA-Ile. Interestingly, we identified three microsatellites (SSR) in P. antarcticus mitogenome using MISA. A (TA) 6 SSR is located in the codon region of ND4 genes, another (TA) 6 SSR and an (A) 10 SSR are both situated in the control region.
Based on nucleotide sequences of 16 Achelata species mitogenome available in the GenBank, a phylogenetic analysis was carried out to investigate the evolution position of P. antarcticus using the maximum-likelihood (ML) method with 1000 bootstrap replicates. The result (Figure 1) showed that P. antarcticus was first cluster to Ibacus ciliatus and Ibacus alticrenatus, which is consistent with the expected phylogenetic relationship.

Disclosure statement
No potential conflict of interest was reported by the authors.