COLLETTE and RUSSO: SPANISH MACKERELS 



from the posterior notch of the posttemporal onto 

 the supracleithrum. This short canal lies ventral 

 to the dorsal process of the supracleithrum and 

 extends to the posterior edge of the bone. 



The maximum width of the supracleithrum 

 varies from 42 to 75% of the total length of the 

 bone in the three genera. The supracleithrum is 

 widest in Grammatorcynus (72-75% of length), 

 Scomberomorus niphonius (55-62% ), and S. line- 

 olatus (53-57%). It is narrowest in S. multiradia- 

 tus (43-53%), sinensis (45-46%), semifasciatus 

 (46-51%), and sierra (45-49%). Specimen size is a 



a 



FIGURE 41. — Left supracleithra in lateral view. a. Scomber- 

 omorus lineolatus. Cochin, India, 786 mm FL, 1.5 x . b. Scom- 

 beromorus multiradiatus, New Guinea, 294 mm FL, 3x. c. 

 Acanthocybium solandri, Caribbean Sea, 1,240 mm FL, 1 x . d. 

 Grammatorcynus bilineatus, Marshall Is., 424 mm FL, 2x . 



factor because the smallest species of Scomber- 

 omorus (S. multiradiatus) and small specimens 

 of large species tend to have narrower supra- 

 cleithra than large species and large specimens. 

 For example, the percentages for a series of five 

 S. commerson are as follows: 354-364 mm FL, 

 38-43%; 493 mm, 42%; 1,052 mm, 39-44%; 1,155 

 mm, 47%. 



The dorsal process is prominent in Acanthocyb- 

 ium (Fig. 41c), Grammatorcynus (Fig. 41d), S. 

 cavalla, commerson, and lineolatus (Fig. 41a). It 

 is small but distinct in S. multiradiatus (Fig. 

 41b). In most of the other species of Scomberomo- 

 rus, it tends to be less sharply set off from the 

 main body of the supracleithrum. 



Supratemporal 



The supratemporal (Fig. 42) is a thin flat 

 triangular bone lying just underneath the skin 

 where its lateral process articulates with a dorsal 

 articular surface on the pterotic. Mago Leccia 

 (1958:324) failed to find the supratemporal in his 

 specimens. The anterior margin is concave and 

 the convex posterior margin slightly overlaps the 

 dorsal arm of the posttemporal. The supratem- 

 poral is deeper (from the tip of the median ante- 

 rior arm to the base) than wide (tip of lateral 

 anterior arm to tip of posterior arm), width 

 49-84% of depth in Scomberomorus and Acan- 

 thocybium. However, the supratemporal is wider 

 than deep in Grammatorcynus (Fig. 42d), width 

 101-113% of length. Acanthocybium (Fig. 42c) has 

 a wider supratemporal (84-93% of depth) than do 

 the species of Scomberomorus (49-79%). The wid- 

 est supratemporals in Scomberomorus are in 

 niphonius (73%), guttatus (67-79%), sierra (69- 

 74%), and semifasciatus (63-72%). The narrowest 

 supratemporals are in multiradiatus (49-50%), 

 koreanus (54%), brasiliensis (53-59%), queens- 

 landicus (55-60%), and sinensis (54-62%). 



The supratemporal bears a prominent lateral 

 line canal that extends out almost to the tips of 

 all three arms. Devaraj (1977:45) did not specifi- 

 cally mention the presence of this canal. In Scom- 

 beromorus, the canal along the anterior margin 

 of the bone is the longest and best developed, and 

 the canal along the lateral side the next longest. 

 In most species of the genus, the first canal has 

 three or four posteriorly directed branches. Speci- 

 mens of S. niphonius and S. semifasciatus (Fig. 

 42a) had five or six branches. Two specimens of 

 S. multiradiatus had only a single posterior 

 branch. A specimen of S. munroi had no posterior 



605 



