Phylogenetic Relationship within the Genus Carcharhinus on the Basis of Lemon shark (N. brevirostris) Position

Abstract

Many doubts have not been answered about the phylogenetic relationship of the sharks. The morphological models and molecular studies, frequently used these days, can put some species into different order or suborder. The sharks contain about 1% of all fishes, separated into 8 orders. Within these, the largest group is the genus Carcharhinus, which includes economically important sharks. A lot of different analyses were done to determine the relationship among these genera. Most of them indicate that phylogenetic relationships at most taxonomic levels remain mysterious for this genera. This study was applied to determine the interrelationship between Carcharhinus and Negaprion genera based on the lemon shark position and to find out the possible paraphyletic situation of genus Carcharhinus, via using ribosomal ITS2 region and mtDNA D-loop for comparison and to get more reliable findings. As a result, based on the ribosomal ITS2 analyses, the lemon shark is placed within the genus Carcharhinus, on the other hand, the lemon shark finds a place outside of the genus Carcarhinus according to the mtDNA D-loop analyses results. Different findings regarding the position of the lemon shark indicate that it is necessary for more accurate results of the study by using more samples and more gene data.