NO. 3537 SHARK GENUS ISURUS — GARRICK 667 



22 

 credits it with having -^ teeth in each side of the jaws. In all other 



makos so far reported there is a range of 77-- — —^ teeth in each side of 



° 10 to 15 



the jaws. Murray's account stresses the fact that his species has many 

 teeth, thereby lessening the likehhood that his count is in error. How- 

 ever, because no other mako has been reported with a comparable 

 number of teeth, and in view of the fact that Murray's count is twice 

 that for other makos, I beUeve that Mm-ray's count should be 

 regarded as in error. I, therefore, follow Smith (1957, p. 92) and some 



22 

 earlier workers in treating Murray's count of -^ as being a total count 



rather than the count of the teeth in each side of the jaws. 



Examination of my data on the proportional dimensions of the 

 makos used in this study shows that only in pectoral fin length is there 

 any clear-cut evidence of the existence of more than one species. In 

 figiu'e 1, where the length of the pectoral fin relative to prepectoral 

 length is expressed against total length, five specimens stand well apart 

 from the remainder in having considerably longer pectorals. These 



no 



z 



if) trlOO 

 < O 



u u 



UJ Ld 



°- °- 80 

 S O 

 O ^ 



is™ 



^ z 60 



A A 



* 



O ATLANTIC 



•if PACIFIC 



9 INDIAN 



▲ PACIFIC OR INDIAN 



•^ UNKNOWN 



qomphodon , .1 



\ aincanus ^ 



-^ 



O-tigris 



o 



glaucus 



^ • 



o • 



1500 2000 2500 3000 



TOTAL LENGTH IN MM 



Figure 1. — hums, separable into long-finned and short-finned species by the length of the 

 pectoral fin relative to prepectoral length (identified specimens are types of the nominal 

 species). 



specimens include three from the central Pacific (data from Dr. Donald 

 W. Strasbiu-g) and two specimens suppUed by Dr. Tokiharu Abe. 

 The latter two were taken by Japanese long-line vessels in either the 

 Pacific or Indian Oceans. The only specimen that does not obviously 

 fit within the two groupings in figure 1 is the type of I. gomphodon 

 which is more or less intermediate though favoring the short-finned 

 group. However, as already discussed, the dimensions of /. gom- 

 phodon are suspect, and its fins are probably relatively shorter than 

 its illustrated total length suggests. On this basis /. gomphodon can 

 be aligned with the short-finned group. 



