Taxonomic assessment of sharks, rays and guitarfishes (Chondrichthyes: Elasmobranchii) from south-eastern Arabia, using the NADH dehydrogenase subunit 2 (NADH 2) gene Author Henderson, Aaron C. Author Reeve, Alan J. Author Jabado, Rima W. Author Naylor, Gavin J. P. text Zoological Journal of the Linnean Society 2016 2015-10-05 176 2 399 442 http://dx.doi.org/10.1111/zoj.12309 journal article 10.1111/zoj.12309 0024-4082 5356370 SPHYRNIDAE (HAMMERHEAD SHARKS) Three Sphyrna species were examined during the present study, namely S. lewini , S. zygaena and S. mokarran , and each formed a separate cluster with a mean between-group distance of 15.10 ± 0.12%. Naylor et al . (2012) reported two main clusters within S. lewini , designated S. lewini 1 (Atlantic and Indian Ocean specimens) and S. lewini 2 (Pacific specimens). Specimens of S. lewini from the present study clustered with S. lewini 1, within which they grouped most closely with other Indo-Pacific specimens. Similarly, Naylor et al . (2012) found two main clusters within S. mokarran , representing Atlantic ( S. mokarran 1) and Pacific ( S. mokarran 2) specimens. The two S. mokarran speci- mens from the present study clustered with S. mokarran 1. Lastly, only one cluster was reported for S. zygaena by Naylor et al . (2012) , and the addition of the current specimens did not alter this arrangement.