Sphyrna Rafinesque, 1810a

Ebert, David A., White, William T., Ho, Hsuan-Ching, Last, Peter R., Nakaya, Kazuhiro, Séret, Bernard, Straube, Nicolas, Naylor, Gavin J. P. & De Carvalho, Marcelo R., 2013, An annotated checklist of the chondrichthyans of Taiwan, Zootaxa 3752 (1), pp. 279-386 : 339-340

Genus Sphyrna Rafinesque, 1810a

Hammerhead Sharks / ḝěḛé

Sphyrna Rafinesque, 1810a: 60 . Type species: Squalus z ygaena Linnaeus, 1758, by subsequent designation ( Bonaparte, 1838).

Sphyrna lewini ( Griffith & Smith, 1834)

Scalloped Hammerhead / Ṏkḝěḛ

Zygaena lewini Griffith & Smith, 1834: 640 , pl. 50. No types known; from south coast of Australia [ New Holland] .

Local synonymy: Sphyrna lewini: Teng, 1958: 10 , fig. 7; Teng, 1962: 79, fig. 21; Chen, 1963: 12, fig. 3 (THUP 921, THUP 154); Yang & Chen, 1971: 2, fig. 2; Yang, 1981: 4, fig. 3; Shen, 1984a: 63, fig.; Chen et al., 1988: 389; Chen & Yu, 1986: 141; Chen et al., 1990: 156; Chen & Joung, 1993: 68, pl. 9 (fig. 2); Shao et al., 1993: 132; Liu & Chen, 1999: 218; Chen, 2004: 22; Shen & Wu, 2011: 74, fig.

Taiwan voucher material: (5 spec.) NMMB-P 4210 , Penhwo , 1 Aug 1957 ; NMMB-P 4212 , Keelung, 1 Aug 1963 ; NMMB-P 6279-1 , Wu-Chi , Taichong, 23 Oct 1964 ; UF 159198, juvenile male 520 mm TL, Da-xi, 23 May 2005 ; NMMB-P 15780 , 27 Sep 2010 .

Remarks: One of the most abundant species in the commercial shark fishery off northeastern Taiwan; also common off the west and south of Taiwan; Chen et al. (2002) reported that over an average of 370 tons of S. lewini were landed annually at Nan-fang-ao between 1989 and 1994, which represents about 20% of the shark catch in this area, with the peak season from September to March. A recent molecular study revealed that this species is possibly a species complex with two species occurring in the Indo-West Pacific ( Naylor et al, 2012).

Conservation status: Endangered.

Sphyrna mokarran ( Rüppell, 1837)

Great Hammerhead / âẵḝěḛ

Zygaena mokarran Rüppell, 1837: 66 , pl. 17 (fig. 3). Lectotype: SMF 3590 (stuffed), male 2515 mm, Massawa, Eritrea, Red Sea; lectotype designation by Klausewitz (1960).

Local synonymy: Sphyrna mokarran: Chen, 1948: 39 ; Teng, 1958: 8, fig. 6; Teng, 1962: 75, fig. 20; Chen, 1963: 11 (TFRI 103119, TFRI 103262); Shen, 1984a: 63, fig.; Chen & Yu, 1986: 141; Chen & Joung, 1993: 68, pl. 9 (fig. 3); Shen & Wu, 2011: 74, fig.

Taiwan voucher material: No specimens examined in this study.

Remarks: Appears to be rarely caught in Taiwanese waters presently; serious declines in the populations of Sphyrna species have been reported worldwide, and the coastal habits of this species likely exacerbates the problem.

Conservation status: Endangered.

Sphyrna zygaena ( Linnaeus, 1758)

Smooth Hammerhead / ŠĀḝěḛ

Squalus zygaena Linnaeus, 1758: 234 . Syntype: NRM LP 88, male embryo 215 mm (see Fernholm & Wheeler, 1983). Type locality: Mediterranean Sea and Atlantic (inc. Spain, France, Italy, Greece, Syria).

Local synonymy: Zygaena malleus: Günther, 1870: 381 ( Formosa) . Sphyrna zygaena : Jordan & Evermann, 1902: 318; Jordan & Richardson, 1909: 162; Fowler, 1941: 217 ( Formosa); Chen, 1948: 39; Liang, 1951: 3; Chen, 1956: 20; Teng, 1962: 75; Chen, 1963: 14, fig. 4 (THUP 1961); Shen, 1984a: 63, fig.; Chen & Yu, 1986: 142; Chen & Joung, 1993: 68, pl. 9 (fig. 4); Chen, 2004: 22; Shen & Wu, 2011: 74, fig. Cestracion zygaena: Nakamura, 1936: 37 .

Taiwan voucher material: (3 spec.) NMMB-P 6279 , Taichong , 23 Oct 1964 ; NMMB-P 6296 , Taichong , 1 Feb 1963 ; NMMB-P 6569 , Kaohsiung, 4 Aug 1965 .

Remarks: Common in the landings of the commercial shark fishery off northeastern Taiwan; average annual landings at the Nan-fang-ao fish market between 1989 and 1994 was 65.5 tons, about 3.6% of shark landings ( Chen et al., 2002).

Conservation status: Vulnerable.