FISHERY BULLETIN: VOL. 73, NO. 3 



the dorsal half of the fish. A patch of scales is also 

 present around the base of the pelvic fins. 

 Cybiosarda has a band of scales dorsally extending 

 along the entire midline (Figure la). Ventrally, 

 scales are present around the base of the pelvic fins 

 and a broad band of scales extends from the anal 

 fin origin posterodorsally to the caudal peduncle. 

 The peduncular region is entirely covered with 

 scales except for the distal margin of the caudal 

 keel. Orcynopsis (Figure lb) has fewer scales than 

 Cybiosarda. The band of scales along the dorsal 

 midline is narrower and ends at the dorsal finlets. 

 Ventrally, Orcynopsis has scales around the bases 

 of the pelvic and anal fins. The caudal peduncle is 

 naked except for the caudal keel. Gymnosarda is 

 completely naked posterior to the corselet except 

 for the lateral line, dorsal fin base, and caudal keel 

 (Figure 2a). 



The corselet, composed of enlarged scales, is well 

 defined in the pectoral region of bonitos. It ex- 

 tends from the dorsal end of the gill slit to the tip 

 of the pectoral fin, except in Sarda and Allothun- 

 nus. Anterior and ventral to the pectoral fin base, 

 the scales are smaller than on other parts of the 

 corselet in bonitos. In Sarda, an extra wing of the 

 corselet extends dorsally toward the origin of the 

 first dorsal fin. Allothunnus has the most exten- 

 sive corselet, covering most of the area between 

 the first dorsal fin base and the pectoral fin. 



distances between the snout and the origins of the 

 anal and second dorsal fins. Cybiosarda and Or- 

 cynopsis both have high first dorsal, second dorsal, 

 and anal fins compared to other bonitos. Gym- 

 nosarda has a differently shaped head than do 

 other bonitos: the interorbital distance is much 

 wider, the eyes are larger, the postorbital distance 

 is shorter, and the distance between the origins of 

 the pectoral and pelvic fins is much larger. In ad- 

 dition, Allothunnus has large eyes and a very 

 short snout and maxilla. 



Because of small sample size, restricted 

 geographical distribution, or both, morphometric 

 data were combined for each of four species: 

 Cybiosarda elegans, Sarda australis, Gymnosarda 

 unicolor, and Allothunnus fallai. Three popula- 

 tions of Orcynopsis unicolor are compared: Israel, 

 Lebanon, and Tunisia. The southeast Pacific 

 population of Sarda chiliensis (nominal S. c. 

 chiliensis) is compared with the northeast Pacific 

 population {S. c. lineolata). The population of Sar- 

 da orientalis in the eastern tropical Pacific 

 (nominal S. o. velox) is compared with the only 

 other suflficiently large sample, northwest Pacific. 

 Three populations of S. sarda are compared: west- 

 ern Atlantic, Mediterranean Sea (including the 

 Black Sea), and the Gulf of Guinea. 



Meristic Characters 



Morphometric Characters 



Twenty-six measurements, in addition to fork 

 length, were routinely made on all specimens des- 

 tined to be dissected to insure that these data 

 would be available if needed. Preserved material 

 was also measured until an adequate sample was 

 obtained. Measurements follow the methods of 

 Marr and Schaefer (1949) as modified by Gibbs and 

 Collette (1967). Morphometric characters can be 

 used to separate genera, species, and populations 

 within species. Tables showing the 26 characters 

 as thousandths of fork length and 8 characters as 

 thousandths of head length are presented in the 

 systematic section of the paper. Most of the 

 characters are best used at the species level; 

 therefore, only a summary table of the means of 

 proportions (Table 1) is presented in this section. 



Orcynopsis is short-bodied and short-headed. It 

 has shorter snout-anal and snout-second dorsal 

 distances than do the other bonitos. Cybiosarda is 

 also relatively short-bodied. Allothunnus is the 

 most elongate of the bonitos and has the greatest 



Countable structures are of special value 

 systematically because they are relatively easy to 

 record unambiguously and because they are easy 

 to summarize in tabular fashion. Meristic 

 characters that have proved valuable systemat- 

 ically in the Sardini include numbers of fin rays 

 (first dorsal spines, second dorsal rays, dorsal 

 finlets, anal rays, anal finlets, pectoral rays), gill 

 rakers, teeth (especially on the upper and lower 

 jaws), vertebrae, and laminae in the olfactory 

 rosettes. Olfactory laminae are discussed as the 

 last section under soft anatomy. The other meris- 

 tic characters are discussed in the relevant os- 

 teological sections of the paper. 



Soft Anatomy 



The relative position, shape, and size of the 

 various internal organs provide valuable diagnos- 

 tic characters. Within the genus Sarda, these 

 characters are useful at the species level. For pur- 

 poses of discussion, the characters in the soft ana- 

 tomy are divided into five sections: viscera, vas- 



524 



