FISHERY BULLETIN: VOL. 73. NO. 3 



Vertebral Number 



Vertebrae may be divided into precaudal (ab- 

 dominal) and caudal. The first caudal vertebra is 

 defined as the first vertebra that bears a notably 

 elongated haemal spine and lacks pleural ribs. 

 Vertebral counts include the ural centrum which 

 bears the hypural plate. 



As with dorsal spines, the bonitos fall into three 

 groups based on total number of vertebrae (Table 

 9): few vertebrae (37-39) in Orcynopsis, Gym- 

 nosarda, and Allothunnus; moderate number 

 (42-48) in Cybiosarda and three species of Sarda; 

 and many (50-55) in S. sarda. These groups can be 



further subdivided by dividing the total count into 

 precaudal plus caudal. Orcynopsis usually has 

 18-1-20 = 38; Gymnosarda 19-1-19 = 38; and 

 Allothunnus 20-1-19 = 39. Cybiosarda has more, 

 usually (22-23) -I- (24-25) = 47, than the middle 

 group of Sarda species, which usually have (23- 

 25) -I- (20-22) = 44-45. Precaudal, caudal, and total 

 counts all vary more in S. sarda than in other 

 species of bonitos. 



Vertebral Column 



The neural arches and spines are stout and 

 laterally flattened on the first to fifth vertebrae in 



Table 9.-Numbers of precaudal, caudal, and total vertebrae in species of Sardini. 



Precaudal vertebrae 



Species 



17 18 19 20 21 22 23 24 25 26 27 28 



Orcynopsis unicolor 



Cybiosarda elegans 



Sarda australis 

 Sarda chiliensis: 



NE Pacific 



SE Pacific 



Total 



Sarda orientalis: 

 Indo-W Pacific 

 E Pacific 



Total 



Sarda sarda: 

 W Atlantic 



Mediterranean-Black Sea 

 Gulf of Guinea-S. Africa 



Total 



Gymnosarda unicolor 



Allothunnus fallal 



Orcynopsis unicolor 

 Cybiosarda elegans 

 Sarda australis 



Sarda chiliensis: 

 NE Pacific 

 SE Pacific 



Total 



Sarda orientalis: 

 Indo-W Pacific 

 E Pacific 



Total 



Sarda sarda: 

 W. Atlantic 



Mediterranean-Black Sea 

 Gulf of Gulnea-S. Africa 



Total 



Gymnosarda unicolor 



Allothunnus lallai 



2 27 



17 



6 2 

 1 11 



3 13 13 



Caudal vertebrae 



19 20 21 22 23 24 25 26 27 N 



572 



