10 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 119 



Genus Sphyrna Rafinesque 



Cestracion Klein in Walbaum, 1792, p. 580. (Type species, Squalus zygaena 



Linnaeus, by subsequent designation of Gill, Ann. Lyceum Nat. Hist. New- 

 York, vol 7, p. 403, 1861; name inadmissable, as result of International 



Commission rulings of 1907 and 1910.) 

 Sphyrna Rafinesque, 1810, pp. 46, 60. (Type species, Squalus zygaena Linnaeus, 



by subsequent designation of Jordan and Gilbert, U.S. Nat. Mus. Bull. 16, 



p. 26, 1883.) 

 Sphyrnias Rafinesque, 1815, p. 93. (Name substituted for Sphyrna Rafinesque, 



1810.) 

 Cestrorhinus Blainville, 1816, p. 121. (Type species, Squalus zygaena Linnaeus, 



by subsequent designation of Fowler, Bull. Geol. Surv. New Jersey, vol 4, 



p. 77, 1911.) 

 Zygaena Cuvier, 1817, p. 127. (Type species, Squalus zygaena Linnaeus, by 



absolute tautonymy; genus name preoccupied by Zygaena Fabricius, 1775, 



for Lepidoptera.) 

 Zygoena Risso, 1826, p. 125. (Emended spelling for Zygaena Cuvier, 1817.) 

 Sphyrnichthys Thienemann, 1828, p. 408. (Substituted for Sphyrna Rafinesque, 



1810.) 

 Zygana Swainson, 1839, p. 318. (Apparently a typographical error; should be 



spelled Zygaena.) 

 Platysqualus Swainson, 1839, p. 318. (Type species, Squalus tiburo Linnaeus, by 



original designation.) 

 Sphyra van der Hoeven, 1855, p. 68. (Emended spelling for Sphyrna Rafinesque, 



1810.) 

 Reniceps Gill, 1861, pp. 403, 412. (Type species, Squalus tiburo Linnaeus, by 



original designation.) 

 Eusphyra Gill, 1861, pp. 403, 412. (Type species, Zygaena blochii Cuvier, by 



original designation.) 



Phylogeny. — There has, in the past, been some question as to 

 whether the genus Sphyrna has had a nionophyletic or polyphyletic 

 origin. Members of the genus are characterized by certain apparently 

 basic morphometric characters, in addition to the ^^'idely expanded 

 head, which indicate derivation from a single common ancestor. The 

 most important of these are: No middorsal ridge on the posterior 

 part of the back; dermal denticles not closely overlapping; teeth 

 moderately to strongly oblique; labial furrow either small or absent; 

 body deeply compressed ; pectoral fin short. Of the above characters, 

 the last two may have evolved in direct response to the lateral widening 

 of the head, and thus should be viewed with caution. The remaining 

 characters are not likely to have been affected by such a change, and 

 are thus regarded as fimdamental evidence of a close relationship 

 among the species of Sphyrna. Perhaps the most convincing study 

 supporting a monophyletic derivation has resulted from the work by 

 Starr and Fosberg (1957, pp. 292-295, figs. 1 and 2), m which serum 

 proteins were analyzed using electrophoretic techniques. Work done 

 by various investigators (the most important and extensive being that 

 of C. G. Sibley, of Cornell University, on birds) has shown that the 



