COLLETTE and RUSSO: SPANISH MACKERELS 



FIGURE 19. — Skulls in ventral view. a. Acanthocybium solandri, Caribbean Sea, 1,240 mm FL. 



bilineatus, Scott Reef, Timor Sea, 453 mm FL. 



b. Grammatorcynus 



bones. The left and right orbits are partially 

 separated by the basisphenoid. The sclerotic 

 bones enclose the eyeballs. 



Frontal. — The frontals are paired bones that 

 form the largest portion of the dorsal surface of 

 the neurocranium. Anteriorly they are pointed, 

 and posteriorly they become expanded. Anterior- 

 ly, the frontals overlap the dorsal surface of the 

 ethmoid bone, the inner edge of the nasals, and 



the dorsal surface of the lateral ethmoid. The 

 midlateral aspect is thickened to form the orbital 

 roof. Posteriorly, they are bounded by the supra- 

 occipital and parietals. Posterolaterally, they 

 overlap the pterotics and just anterior to the 

 pterotics, cover the sphenotics. Ventrally, each 

 frontal bears a sheet of bone, the orbital lamella, 

 which is bounded by the sphenotic posteriorly, 

 lateral ethmoid anteriorly, and pterosphenoid 

 mesially. On the base of the orbital lamella may 



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