Hemigaleidae

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 : 34-35

Hemigaleidae (weasel sharks)

Hemigaleus microstoma (sicklefin weasel shark)

( fig. 21)

In total, 31 specimens of this species were included. They consist of one specimen collected from Singapore, six from the Philippines, and 24 from Borneo and thus represent only some of the more central elements of the Indo-West Pacific distribution of this species. Two of the specimens from the Philippines were treated by Com- pagno et al. (2005a) (i.e., GN4324 5 BRU 123 and GN4325 5 JPAG 216) as H. microstoma . One of the specimens from Borneo was also vouchered (GN3694 5 IPPS BO483). These 31 specimens comprised a single cluster, including a weakly supported subcluster comprised of a subset of specimens from Borneo. The range in pairwise differences among all 31 specimens of this species was 0–13 and the average was 4.9.

Hemigaleus australiensis (Australian weasel shark)

( fig. 21)

Our analysis included six specimens of this newly described species (see White et al., 2005) from Western Australia, and the Timor and Arafura seas off the coast of northern Australia. Two of these specimens came from the Australian National Fish Collection (the holotype GN4913 5 ANFC H 5949-01 and GN4914 5 ANFC H 5949-02 ). Within this cluster, two specimens, one from Western Australia and one from the Arafura Sea, grouped together in a subcluster distinct from the other four specimens. The range in pairwise differences among all six specimens of this species was 0–11, with an average of 6.5. The two specimens in the former subcluster differed by one base, and the range in pairwise differences among the remaining four specimens was 0–5 (with an average of 3.2). The mean of the pairwise differences between the two subclusters of H. australiensis was 9.8. The mean of the pairwise differences between specimens of H. australiensis and those of H. microstoma was 94.6 ; this result strongly supports the distinction between these two congeners.

Paragaleus sp. ( fig. 21)

A single specimen of Paragaleus from Phuket, Thailand, grouped outside both of the known species of Paragaleus , along with the two species of Hemigaleus . The average of the pairwise differences between this specimen and those of P. randalli was 128.9. The average of the pairwise differences between this specimen and those of P. pectoralis was 122.7. We have given this specimen the designation Paragaleus sp. It possibly represents an undescribed Paragaleus species , however, comparisons with the two described species of Paragaleus not included here would also be valuable. Given its substantial difference from the other two Paragaleus species , it may, however, be a case of incorrect generic identification, and the possibility that it represents a species of Chaenogaleus should be explored.

Paragaleus randalli (slender weasel shark) ( fig. 21)

Our analysis included a total of 17 specimens belonging to this species, two of which were vouchered (GN4182 5 MZB 15.506 and GN4191 5 MZB 15.507). The analysis yielded a single cluster. The specimens in this cluster included 16 samples from Borneo and a single specimen from the Philippines. The range in pairwise differences among specimens in this cluster was 0–9; the average of pairwise differences among specimens of this species was 2.9. All of the localities sampled in this study fall well outside the originally described range of Paragaleus randalli (i.e., Bahrain and western Indian Ocean), but within the range of the similar looking congener Paragaleus tengi (straighttooth weasel shark) which might lead to the suspicion that these tissue samples were actually derived from specimens of P. tengi . However, unpublished sequence data from NADH2 indicate no significant differences in sequence between specimens identified as P. randalli from the Persian Gulf and those of the 17 specimens from Southeast Asia used in the current study. Furthermore, vertebral counts examined (by PL and WW) from three specimens originally identified as Paragaleus tengi from Borneo, range in number between 164 and 171 which is outside the reported range for P. tengi (131–135) but consistent with the range given for P. randalli (165–186). Taken togeth- er, these observations suggest that P. randalli has a more extensive distribution than suggested in its original description ( Compagno et al., 1996) extending from the western Indian Ocean to Southeast Asia. They also suggest that P. randalli , rather than P. tengi , is the dominant form of Paragaleus in Borneo.

Paragaleus pectoralis (Atlantic weasel shark)

( fig. 21)

The analysis yielded a cluster consisting of six specimens of this species, all from western Africa (i.e., from Mauritania, Senegal, and Sierra Leone). These specimens are generally representative of the distribution of this species, which extends throughout the northern half of the western coast of Africa. The range in pairwise differences among specimens within this cluster was 0–5, with an average of 2.9. The average of the pairwise differences between specimens of P. pectoralis and P. randalli was 118.

Hemipristis elongata (snaggletooth shark) ( fig. 21)

Our analysis included a total of 14 specimens of this monotypic genus, nine from Borneo and five from the Arafura Sea off northern Australia ; these represent only a subset of the distribution of this species which includes much of the Indo-West Pacific, with the Red Sea as the type locality. One of these specimens is represented by a voucher (GN4195 5 CAS 229035 ). The analysis yielded a single cluster. The range in pairwise differences among specimens was 0–5 ; the average was 2. There is some evidence of geographic substructure within this cluster with the Australian specimens grouping apart from the Borneo specimens, however the signal is weak as the average of the pairwise differences between specimens from the two localities was only 3.5.