NO. 3539 HAMMERHEAD SHARKS — GILBERT 65 



Brazil: MCZ 463 (paratype of S. bigelowi), Kio de Janeiro. French 

 Guiana: MNHN 1019 (lectoparatype of Zygaena tudes), Cayenne. 

 Surinam: ANSP 377 (1), ANSP 516 (1), (no further data); USNM 

 156721 (1), 1 mi. southeast of Paramaraibo Ught ship; USNM 159197 

 (1), USNM 159199 (1), 06°27' to 06°25'N., 55°05' to 55°10'W.; 

 USNM 159227 (2), 06°20.5'N. to 06°19.5'N., 54°54'W. to 54°49'W.; 

 USNM 159228 (4), USNM 159229 (4), 06°22'N., 55°04' to 55°08'W. 

 United States (Mississippi): USNM 195957 (8), Gulf of Mexico, 

 29°54'N., 88°06'W. (Oregon Sta. 2110). Uruguay: USNM 87682 

 (holotype of Sphyrna bigelowi), no further data; USNM 120751 (para- 

 type of S. bigelowi), no further data. Venezuela: USNM 123217 

 (head), Gulf of Venezuela, Anway Bay. 



Mediterranean Sea: France: MNHN 1049 (lectotype of Zygaena 

 tudes), Nice. 



Nomenclature. — The original description of Zygaena tudes (Va- 

 lenciennes, 1822, pp. 225-226, pi. 12, figs, la and 6) was based on 

 specimens, in the Museum National d'Histoire Naturelle, from Nice, 

 France (cat. no 1049); Cayenne, French Guiana (cat. no. 1019); and 

 Coromandel, India (specimen lost). As has previously been shown, 

 these specimens comprise two species: The one currently called 

 Sphyrna tudes (Gilbert, 1961, p. 480), which is characterized by the 

 tip of the first dorsal fin extending beyond the insertion of the pelvic 

 fins, the first and fifth gill sUts nearly equal in length, with the latter 

 situated above the insertion of the pectoral fin, and a small maximum 

 size (perhaps not over 4 or 5 feet) ; and the one presently called Sphyrna 

 mokarran (Gilbert, 1961), characterized by the tip of the first dorsal 

 fin not reaching the insertion of the pelvic fins, the first gill sht longer 

 than the fifth gill slit, with the latter situated posterior to the insertion 

 of the pectoral fin, and a large maximum size (up to 20 feet). I here 

 restrict the name tudes to those specimens from Nice and Cayenne, 

 and designate as lectotype of Zygaena tudes the 346 mm. female (no. 

 1049) on which the illustration in the original description was based 

 (pl. 4). 



Diagnosis.— Characters mentioned in the diagnosis of the subgenus 

 Platysqualus are not repeated here. 



Sphyrna tudes differs from the closely related S. corona and S. media 

 in the following characters: Anterior margin of head straighter (par- 

 ticularly in large specimens), with a pronounced median notch; inner 

 narial groove present; anterior-median pore patch on underside of 

 head divided into two broadly rounded lobes and separated by a 

 deep, wide, median indentation (fig. 226); narial depression sUghtly 

 deeper; first dorsal fin of larger specimens (600 mm. or more) more 

 erect and more broadly triangular, a Une drawn perpendicularly from 

 apex of fin intersecting base of fin. 



219-937—67 5 



