SHARK GENUS ISURUS — GARRICK 



665 



sustained interest and discussions on the problem; and several col- 

 leagues who have read and offered valuable suggestions on the manu- 

 script. The illustrations of the teeth of two makos (figs. 8, 9) are by 

 Peter A. McCrer}^ 



Although the nominal species treated here have been placed in 

 several genera by some authors, opinion has stabilized in more recent 

 years to include them all in Isurus Rafiuesque. It Avill be apparent 

 from the treatment of these nominal species in this account that 

 recognition of Isurus alone is the only possible coiu-se. 



The nominal species of Isurus listed in the order in which they 

 were proposed* are: 



locality 

 Sicily 



species 

 Isurus oxyrinchus * RaJSnesque, 



1810a 

 Isurus spallanzani Rafinesque, 



1810b 

 Squalus (Lamna) cepedii Lesson, 



1830 

 Oxyrhina gomphodon Mliller and 



Henle, 1841 

 Oxyrhina glauca Mtiller and Henle, 



1841 

 Isuropsis dekayi Gill, 1862b 

 Carcharias tigris Atwood, 1869 

 Lamna guentheri Murray, 1884 

 Lamna huidobrii Philippi, 1887 

 Isurus mako Wliitley, 1929 

 Isurus bideni Phillipps, 1932 

 Isurus africanus Smith, 1957 



total length{s) oftype{s) 



Sicily 



Tropical Atlantic 



Japan 



New York 



Massachusetts 



Kurrachee, India 



Chile 



New Zealand 



South Africa 



South Africa 



1830 mm. 



ca. 1700 mm. 



1020 mm., 750 



mm., 660 mm. 

 3100 mm. 

 2690 mm. 

 2580 mm. 

 2900 mm. 



1195 mm. 

 2540 mm. 



The characters separating Isurus from the other two genera, Lamna 

 and Carcharodon, in the family Lamnidae are: upper teeth smooth 

 edged, lacking lateral basal denticles; first dorsal origin definitely 

 behind a vertical through posterior (inner) comer of pectoral fin ; and 

 no secondary lateral keel along anterior part of caudal fin. In Lamna 

 the teeth are smooth edged but have lateral basal denticles, at least 

 in subadults and adults. In Carcharodon the teeth are serrated. 

 Both Lamna and Carcharodon have the first dorsal origin anterior to a 

 vertical through the posterior corner of the pectoral. Lamna, but 



^ See Addendum. 



5 Tortonese (1956, p. 106, ftn. 1) claims that, under Article 19 of "The 

 Code of Zoological Nomenclature," this spelling should be emended to 

 "oxyrhynchus." However, if we consider that Rafinesque used the spelling 

 "oxyrinchus" twice in his 1810a account (once on page 12, and again on plate 

 13) and repeated it in his 1810b account (p. 45), and nowhere used the spelling 

 "oxyrhynchus" we have no reason to believe that "oxyrinchus" was an in- 

 advertent error. Consequently, according to Article 32(b), the spelling 

 "oxyrinchus" must be treated as the correct original spelling and is not to be 

 emended. 



