Abstract

Background:
A genetic analysis was conducted to identify and classify sharks from the families Squalidae and Squatinidae at the Eastern Libyan coast of the Mediterranean Sea.

Aim:
This study was based on COI gene barcoding, and the sequences obtained were matched with global reference databases to ascertain their taxonomic identity and genetic diversity ratio.

Methods:
The sequences were then deposed to the GenBank database through the BankIt submission system where the following accession numbers were assigned: Squalus mitsukurii (PV717998), Squalus megalops (PV718644), Squatina oculata (PV716693), Squatina squatina (PV738303), and Squatina aculeata (PV719649). The phylogenetic evolution tree was constructed by applying the neighbor-joining method (Chromas Pro v1.5 Beta).

Results:
S. mitsukurii was the first confirmed genetic record of the Mediterranean Sea, whereas S. megalops was the first confirmed genetic record of the Libyan coast. In addition, S. oculata, S. squatina, and S. aculeata were genetically confirmed in Libyan waters for the first time. Haplotype network analysis revealed a clear distinction of genetic distance among the species, with little variation among the species. Nucleotide diversity and Tajima D were computed, and both showed a strong deviation from neutrality, which could have been caused by either selective pressures or past demographic changes.

Conclusion:
Collectively, these findings contribute significantly to the ichthyofaunal diversity of Libya and the Mediterranean Sea in general, and they further demonstrate the power of DNA barcoding as a means of recording and preserving shark diversity.

Key words: Squalus mitsukurii; Squalus megalops; Mediterranean Sea; Libya; DNA barcoding.