Sphyrna zygaena (Linnaeus, 1758)

Cicimurri, David J. & Knight, James L., 2009, Late Oligocene sharks and rays from the Chandler Bridge Formation, Dorchester County, South Carolina, USA, Acta Palaeontologica Polonica 54 (4), pp. 627-647 : 635

Sphyrna zygaena (Linnaeus, 1758)

Fig. 5L .

Referred specimens.—BCGM 9078 and 9079, SC 2009.18.12.

Comments.— Sphyrna zygaena is the more common of the two Chandler Bridge hammerhead sharks, and the largest anterior tooth measures 14 mm in total width and 11 mm in total height. Purdy et al. (2001) synonymized S. laevissima (Cope, 1867) with S. zygaena , and Oligo−Miocene references to the former taxon should be emended accordingly (i.e., Leriche 1942; Kent 1994; Müller 1999). Some teeth of S. zygaena are similar to those of Carcharhinus gibbesi , but the cutting edges are completely smooth.

Stratigraphic and geographic range.— Oligocene to Miocene, USA (North and South Carolina, Virginia, Maryland) and Europe .

Figures

Fig. 5. Carcharhiniform sharks from Summerville, upper Chattian. A–D. Carharhinus gibbesi (Woodward, 1889). A. BCGM 9059, juvenile upper anterior tooth, labial view. B. BCGM 9060, adult upper anterior tooth, labial view. C. BCGM 9061, juvenile upper lateral tooth, labial view. D. BCGM 9058, adult lower anterior tooth, labial view. E, F. Physogaleus aduncus (Agassiz, 1835). E. BCGM 9064, upper lateral tooth, labial view. F. BCGM 9066, lower anterior tooth, labial view. G. Physogaleus sp., BCGM 9068, antero−lateral tooth, labial view. H. Rhizoprionodon sp., BCGM 9070, labial view. I, J. Hemipristis serra (Agassiz, 1835). I. BCGM 9073, adult upper lateral tooth, labial view. J. BCGM 9072, juvenile upper lateral tooth, labial view. K. Sphyrna cf. S. media Springer, 1940, BCGM 9077, lateral tooth, labial view. L. Sphyrna zygaena (Linneaus, 1758), BCGM 9079, lateral tooth, lingual view. M. Bythaelurus sp., BCGM 9074, labial view. N–P. Galeorhinus sp. N. BCGM 9081, parasymphyseal tooth, labial view. O. BCGM 9082, antero−lateral tooth, labial view. P. BCGM 9083, lateral tooth, labial view.