COLLETTE and RUSSO: SPANISH MACKERELS 



a 



FIGURE 34. — Left subopercles in lateral view. a. Scomberomorus semifasciatus , New 

 Guinea, 510 mm FL. b. Scomberomorus multiradiatus , New Guinea, 294 mm FL. c. 

 Acanthocybium solandri, Revillagigedos Is., 1,068 mm FL. d. Grammatorcynus bilinea- 

 tus, Marshall Is., 424 mm FL. 



27%). It is also short, relative to the long, narrow 

 subopercle, in Grammatorcynus (25-26%). Dev- 

 araj (1977:33) mentioned differences in the shape 

 of the posteroventral margin and the dorsal edge 

 of the subopercle, but we have not noted any 

 consistent differences between species in these 

 regions. 



Interopercle. — The interopercle (Fig. 35) is 

 roughly oval in shape with a crest on the superior 

 margin. There is a well-developed facet on the 

 mesial side to receive the articular process of the 

 interhyal. The depth of the interopercle varies 

 from 37 to 61% of the length of the bone. The 

 deepest interopercles are in Scomberomorus si- 

 nensis (54-61%, Fig. 35b) and S. sierra (57-58%). 

 The interopercles are moderately deep (50-58%) 

 in seven species: brasiliensis, commerson, ko- 

 reanus, lineolatus, multiradiatus, queenslandi- 

 cus, and tritor. Grammatorcynus (37-42%, Fig. 



35d) and Acanthocybium (40-49%, Fig. 35c) have 

 lower interopercles than most species of Scom- 

 beromorus (Fig. 35a, b). The shallowest inter- 

 opercles in this genus are in S. plurilineatus 

 (45-47%), S. munroi (47-49%), S. niphonius 

 (47-49%), and S. semifasciatus (47-51%, Fig. 35a). 

 A well-formed notch anterior to the crest on the 

 sloping anterior margin in Scomberomorus and 

 Grammatorcynus is relatively poorly developed 

 in Acanthocybium , rendering the superior margin 

 nearly straight. The posterior margin is rounded 

 in Scomberomorus and Grammatorcynus but di- 

 vided into two by a notch in Acanthocybium. 



BRANCHIAL APPARATUS. —The branchial 

 apparatus is composed of the five pairs of gill 

 arches, gill filaments, gill rakers, pharyngeal 

 tooth patches, and supporting bones. The general 

 arrangement in the Scomberomorini (Fig. 36) is 

 similar to that found in other scombrids such as 



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