FISHERY BULLETIN: VOL. 82, NO. 4 



TABLE 8. — Total number of vertebrae in Acanthocybium , Grammatorcynus , and the species of Scomber omor us. 



Species 



31 / / 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 // 62 63 64 N 



1 15 9 



41-43 vertebrae, but S. cavalla has 16-17 pre- 

 caudal and 24-26 caudal, while S. sinensis has 19 

 or 20 precaudal and 21-22 caudal vertebrae (com- 

 pare Tables 6 and 7). 



Vertebral Column 



The neural arches and spines are stout and 

 compressed on the first to the fifth or sixth 

 vertebrae in most species of Scomberomorus. 

 Compressed neural spines extend to the seventh 

 vertebra in S. commerson and Acanthocybium 

 but only to the fourth vertebra in Grammator- 

 cynus. Posteriorly, toward the caudal peduncular 

 vertebrae and caudal complex, the neural spines 

 bend abruptly backward and cover most of the 

 neural groove; caudally they merge into the cau- 

 dal complex as in Thunnus (Kishinouye 1923; 

 Gibbs and Collette 1967) and the bonitos (Collette 

 and Chao 1975). Neuropophyses are present on 

 all centra except the last one or two. The neural 

 prezygapophyses on the first vertebra are modi- 

 fied to articulate with the exoccipital where the 

 vertebral axis is firmly articulated with the 

 skull. They are stronger at the anterior portion of 

 the vertebrae and are spurlike spines on the 

 peduncular vertebrae and in the caudal complex. 

 Neural postzygapophyses arise posterodorsally 

 from the centrum and overlap prezygapophyses 

 posteriorly. The postzygapophyses progressively 

 merge into the neural spine in the peduncular 

 region to disappear by the last 6-8 vertebrae. The 

 basic structure and elements of the neural arches 

 and neurapophyses are similar to those of other 

 scombrids (Kishinouye 1923; Conrad 1938; Mago 

 Leccia 1958; Nakamura 1965; Gibbs and Collette 

 1967; Collette and Chao 1975; Potthoff 1975). 



Variable characters are found on the haemal 

 arches and haemapophyses. Laterally directed 

 parapophyses, arising from the middle of the 

 centrum, appear on the fourth to sixth vertebrae, 

 where the intermuscular bones and pleural ribs 

 are encountered (see section on Ribs and Inter- 

 muscular Bones). The parapophyses become 

 broader and longer posteriorly and gradually 

 shift to the anteroventral portion of the centra. In 

 lateral view, the first ventrally visible parapo- 

 physes are found on the 7th-9th vertebra in 

 Scomberomorus, usually the 8th, on the 6th-7th 

 in Grammatorcynus, and on the 14th-15th in 

 Acanthocybium. 



Posteriorly, the distal ends of the paired para- 

 pophyses meet, forming the first closed haemal 

 arch. The first closed haemal arch is on the 8th 

 vertebra in Grammatorcynus (Fig. 37d), 10th- 

 16th in Scomberomorus (Fig. 37a, b), and 25th- 

 28th in Acanthocybium (Fig. 37c). This location 

 is correlated with the total number of vertebrae 

 (Table 8). Among the species of Scomberomorus, 

 the first closed haemal arch is most anterior in S. 

 cavalla (lOth-llth vertebra, Fig. 37a) and S. 

 sinensis (12th), the two species with the few- 

 est vertebrae (40-43). The most posterior first 

 haemal arch is on the 15th-16th vertebra in S. 

 munroi and S. niphonius (Fig. 37b) and on the 

 14th-15th in S. multiradiatus, species with many 

 vertebrae (48-56). The other 13 species, including 

 S. guttatus and S. maculatus with high vertebral 

 counts (47-53), have the first haemal arch located 

 at an intermediate position, on the 13th-14th 

 vertebra. The haemal spines become elongate 

 and point posteriorly until they abruptly become 

 more elongate on the first caudal vertebra. The 

 paired pleural ribs (see section on Ribs and Inter- 



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