HAMMERHEAD SHARKS GILBERT 



63 



53-275 (9), Panama Bay, between Panama City and Punta Gorda; 

 SU 11882 (holotype of Sphyrna corona), Panama City. 



Diagnosis. — Characters mentioned in the diagnosis of the subgenus 

 Platysqualus are not repeated here. 



Sphyrna corona differs from the closely related S. tudes in much the 

 same way that S. media differs from that species (see diagnosis of S. 

 media). Unlike S. media, however, the shape of the anterior-median 

 pore patch on the underside of the head is very similar in aS*. corona 

 and S. tudes (figs. 22g,h). 



Sphyrna corona differs from S. media in having a broader postorbital 

 process to the chondrocranium, with the anterior edge of this structure 

 anterior, rather than posterior, to the angle formed by the juncture 



Figure 18— Sphyrna corona: a, juvenile female, 371 mm. TL, from Chiapas, Mexico 

 (FMNH 72521, ex 63093); b, head of juvenile male, 402 mm. TL, from Panama Bay 

 (UCLA 53-275), about 0.6 X natural size. (Fig. a drawn by Paul Laessle, fig. b by 

 Dorothea B. Schultz.) 



of the innerorbital and anterior mediorbital cartilages (pis. 7c,d) ; a 

 slightly shallower anterior fontanelle; and longer rostral cartilages. 

 (The last character is discussed at greater length in the diagnosis of 

 S. media.) 



Sphyrna corona also differs from S. media in having: A slightly 

 longer snout (fig. 186); a less deeply falcate anal fin with a more 

 rounded apex (fig. 18a); anterior-median pore patch on underside of 

 head with the posterior margin less broadly rounded and without a 

 pointed median-posterior extension (fig. 22g) ; a more broadly rounded 

 upper precaudal pit in smaller specimens (fig. 21h); and a slightly 

 narrower mouth. Finally, S. corona may not reach as large a max- 



