Bigelow and Schroeder (19^8) included the whale sharks 

 (Rhlncodontldae) and the nurse sharks (Qrectolobidae) eilong with 

 the Isuridae in their suborder Galeoidea. This is the generally- 

 accepted arrangement, except that opinions are divided on the 

 family designation. Lamnidae is the name used by some authors 

 and Is the older family name. 



The validity of the designation Carcharodon A. Smith, I838, 

 presently depends on the stability of the designation Carcharhinus 

 Blainville, I816 (White, Tucker, and Marshall, 1961) . The con- 

 fusion centers on the designation of the type- species of Carcharhinus 

 by Bosc (1816). Although the designation is valid, its acceptance 

 would make Carcharhinus Blainville, I816 a senior objective synonym 

 of Ceircharodon A. Smith, 1838. White et al. (1961) have submitted 

 a proposal, to the International Commission on Zoological Nomen- 

 clature recommending that Bosc's designation be set aside in order 

 that both Carcharhinus and Carcharodon be stabilized in accordance 

 with long established and current usage. 



SPECIES RELATIONSHIPS 



The following discussions summarize briefly cxirrent views on the 

 affinities of species in this family. 



Carcharodon — At present, only one species, C. car char ias 

 Linnaeus, I758, is considered to be valid. Whitley (1939) designated 

 the Australian - New Zealand form as C. albimors , based primarily 

 on the form and position of the fins compared with C. carcharias . 

 However, form and position of fins eire characters that change with 

 growth, and Bigelow and Schroeder (19^8) observed that the accounts 

 and figures of C. eilbimors do not seem to justify the designation 

 of a new species. 



Isurus — Bigelow and Schroeder (19^8) recognized two species, 

 I. oxyrlnchus Rafinesque, I8IO of the Atlantic, I. glaucus Muller 

 % n«^ ff^TilP_, iRUi from the Indo-Pacific, and a third doubtful species, 

 I. guntheri Murray, I88U, the description of which was based on a 

 single specimen from India. None has since been taken, and Smith 

 (1957) synonymized I. guntheri with I. tigris Atwood, 18^. He 

 believed that the tooth coxint given for I^. guntheri ( the supposed 

 diagnostic character for this species) was intended to mean totsJ. 

 count in both jaws, sinc^ the nianber given (22/28) is "exactly 

 double the normal range." Smith recognized three species from 

 South African waters, I. oxyr i nchus , I. glaucus , and I. tigris . 

 Prom his figures, however, I. tigris appears to be more nearly 

 intermediate between I. oxyrinchus and I. glaucus rather than 

 distinctly separable. He based his separation primarily on shape 

 and position of the first dorsal fin, stating that it is higher 

 and more acute in I. tigris . As mentioned above, these characters 



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