The phylogenomic position of the Winghead shark Eusphyra blochii (Carcharhiniformes, Sphyrnidae) inferred from the mitochondrial genome

The complete mitogenome of the Winghead Shark Eusphyra blochii (Carcharhiniformes: Sphyrnidae) is determined in this study, which is 16,727 bp with a nucleotide base composition: 31.6% A, 25.7% C, 13.0% G and 29.7% T, containing 37 genes with the typical gene arrangement pattern and translate orientation in vertebrates. Two start codons (ATG and GTG) and two stop codons (TAG and TAA/T) are found in the protein-coding genes. The 22 tRNA genes range from 67 bp (tRNA-Cys and tRNA-Ser2) to 75 bp (tRNA-Leu1). The phylogenetic position showed that E. blochii clustered with the Sphyrna clade with strong posterior probability (100%).

The hammerhead sharks (family Sphyrnidae) are a small but a highly distinctive group of tropical to temperate coastal and pelagic sharks. The family faces an elevated risk of extinction with several species assessed as threatened on the IUCN Red List of Threatened Species (IUCN 2015). There is also evidence for cryptic species in the Atlantic Ocean (Abercrombie et al. 2005), which presents issues for the identification and monitoring of catches. Molecular identification of hammerhead products can assist catch identification (Abercrombie et al. 2005; Chapman et al. 2009 ) and is becoming increasingly important as conservation and management measures are implemented for these species, such as the 2013 listing of the three larger-bodied species on the Convention on International Trade in Endangered Species (CITES 2013).

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