COLLETTE and RUSSO: SPANISH MACKERELS 



dorsal branch, as pointed out by Devaraj (1977), 

 whereas the ventral branch is longer than the 

 dorsal branch in all species of Scomberomorus. 

 The distance from the anterior end of the ventral 

 branch to the end of the external branch divided 

 by the distance from the tip of the dorsal hook to 

 the end of the external branch is 120-123% in 

 Grammatorcynus, 112-121% in Acanthocybium, 

 and only 87-107% in the species of Scomberomo- 

 rus. Acanthocybium differs from both Scomber- 

 omorus and Grammatorcynus in having the pos- 

 teriorly directed inner branch almost as long as 

 the outer branch. The distance from the tip of the 

 dorsal hook to the tip of the inner branch divided 

 by the distance to the tip of the outer branch is 

 97-99% in Acanthocybium and 54-84% in the 

 species of Scomberomorus and Grammatorcynus. 

 The tooth patch is long and narrow in Acantho- 

 cybium (Fig. 26c), short and wide in Grammator- 

 cynus (Fig. 26d), and with the species of Scom- 

 beromorus in between these extremes. The teeth 

 are fine in all three genera, but a little larger in 

 Acanthocybium and Grammatorcynus than in 

 most species of Scomberomorus. 



The species of Scomberomorus show some dif- 

 ferences in the length of the ventral branch 

 relative to that of the length of the external 

 branch, the relative length of the outer to the 

 inner branch, the relative width of the tooth 

 patch, and the size of the teeth in the tooth patch. 

 Dividing the length of the ventral margin, from 

 the anterior end of the ventral branch to the end 

 of the external branch, by the length of the dorsal 

 margin, from the tip of the dorsal hook to the end 

 of the ventral branch, shows three species of 

 Scomberomorus — sinensis (98-107%), tritor (100- 

 102%), and commerson (94-102%)— to be most 

 similar to Acanthocybium (112-121%). The lowest 

 figures are for S. niphonius (87-88%). Dividing 

 the length of the dorsal margin by the distance 

 from the tip of the dorsal hook to the end of the 

 inner branch shows four species of Scomberomo- 

 rus — plurilineatus (75-84%), munroi (77-79%), 

 lineolatus (72-74%), and semifasciatus (70-73%) 

 — to resemble Grammatorcynus (71-75%). The 

 lowest figures are for S. multiradiatus (54-56%). 

 The tooth patch is very narrow in S. commerson 

 (Fig. 26b), similar to the patch shape in Acantho- 

 cybium but with finer teeth. The tooth patch is 

 also narrow in a 677 mm FL specimen of S. 

 sinensis and reduced to only a single row of teeth 

 in a 1,082 mm specimen. The teeth in S. sinensis 

 are larger than in other species of the genus, at 

 least the same size as in Acanthocybium. The 



widest tooth patch is in S. semifasciatus (Fig. 

 26a), almost as wide as in Grammatorcynus but 

 with much finer teeth. 



Ectopterygoid. — The ectopterygoid (Fig. 27) is 

 a T-shaped bone, the top of the T forming its 

 posterior end. It is joined with the entopterygoid 

 dorsolaterally, the palatine laterally and anteri- 

 orly, and the quadrate and metapterygoid poste- 

 riorly. The dorsal arm of the ectopterygoid is 

 shorter than the ventral arm in Scomberomorus 

 and vice versa in Acanthocybium and Gramma- 

 torcynus. This relationship can be expressed by 

 dividing the dorsal distance (from the anterior 

 end of the bone to the tip of the dorsal arm) by the 

 ventral distance (from the anterior end to the tip 

 of the ventral process). The range is 85-100% in 

 the species of Scomberomorus compared with 

 greater than 100% in Acanthocybium (103-109%) 

 and Grammatorcynus (110-116%). The shank is 

 longer in Acanthocybium than in the other two 

 genera. The posterior edge of the ectopterygoid 

 (from the tip of the dorsal process to the tip of the 

 ventral process) is shorter relative to the ventral 

 distance in Acanthocybium (41-47%) than in the 

 species of Scomberomorus (43-63%) and Gram- 

 matorcynus (64-68%). 



The ectopterygoids of the species of Scomber- 

 omorus are very similar. The shortest ventral 

 distance is in S. sinensis, 85-88% of the dorsal 

 distance, the longest in S. regalis, 99-100%. The 

 shortest posterior edges are in S. niphonius and 

 S. tritor (50-51% of the dorsal distance), the 

 longest posterior edges are in S. koreanus (61- 

 63%), S. plurilineatus (60-63%), and S. semi- 

 fasciatus (59-62%). 



Entopterygoid. — The entopterygoid is elongate 

 and oval in shape (width 23-46% of length) (Fig. 

 28). The outer margin of the entopterygoid is the 

 thickest part of the bone and is attached to the 

 inner margin of the ectopterygoid. The entoptery- 

 goid also connects with the palatine anteriorly 

 and the metapterygoid posterolateral^. The me- 

 sial and posterior borders are free from contacts 

 with other bony elements. The dorsal surface is 

 concave and the smooth convex ventral surface 

 forms the major part of the buccal roof. The 

 anterior end is narrower than the posterior end in 

 most species but a little wider in S. guttatus and 

 S. koreanus. The entopterygoid is narrowest in S. 

 commerson (width 23-28% of length, Fig. 28a) 

 and S. multiradiatus (29%). The shortest and 

 widest entopterygoids are in sinensis (39-46%, 



581 



