Alopiidae

Elasmobranch, Its Implications For Global, Parasitology, Diversity And, Naylor, G. J. P., Sc, Caira, J. N., Ct, Jensen, K., Ks, Rosana, K. A. M., Fl, White, W. T., Csiro, Tas, Last, P. R., Csiro & Tas, 2012, A Dna Sequence-Based Approach To The Identification Of Shark And Ray Species And Its Implications For Global Elasmobranch Diversity And Parasitology, Bulletin of the American Museum of Natural History 2012 (367), pp. 1-262 : 51

Alopiidae (thresher sharks)

Alopias pelagicus (pelagic thresher) ( fig. 35)

The analysis yielded a cluster with weak evidence of two subclusters. The range in pairwise differences among all 20 specimens was 0–12; the average was 6. One subcluster consisted of a total of 10 specimens collected from Borneo, Taiwan, the Philippines, and India. The range in pairwise differences among these specimens was 0–3. The second subcluster consisted of 10 specimens from the Gulf of Mexico and the Gulf of California, as well as one specimen from Taiwan. One of the samples from the Gulf of California was vouchered (GN5402 5 IBUNAM PE9512). The range in pairwise differences among these specimens was 0–7. The average of the pairwise differences between specimens in the two subclusters was 9.9. Although these results do not support the potential existence of a cryptic species of Alopias off Baja California as suggested by Eitner (1995), they do provide some support for the existence of greater diversity in this genus than currently thought. We note that included here is a specimen (GN4309 5 JPAG 117B) treated by Compagno et al. (2005b) as the first record of A. vulpinus from the Philippines, which clusters among specimens of A. pelagicus . This result suggests that the identity of this specimen should be reconsidered.

Alopias vulpinus (thresher shark) ( fig. 35)

The 11 specimens of this species included in the analysis were collected from both the western North Atlantic and the eastern Pacific oceans. While our analysis lacked representation from throughout much of the distribution of this species, it revealed no evidence of structure between the eastern and western regions of North America. The range in pairwise differences among specimens in this cluster was 0–2, with an average of 0.9. However, the average of the pairwise differences between specimens of A. vulpinus and those identified as A. pelagicus was 97.

Alopias superciliosus (bigeye thresher) ( fig. 35)

Little difference was seen among the nine specimens in the analysis, which included specimens from Virginia, Florida, Taiwan, Senegal, Gulf of California, and the Philippines, and thus represented much of the global distribution of this species. The range in pairwise differences among these specimens was 0–8, with an average of pairwise differences of 2.8. For comparative purposes we note that the average of the pairwise differences between specimens of A. superciliosus and those of A. pelagicus was 120.1 and between specimens of A. superciliosus and those of A. vulpinus 118.7.