Collette and Gillis. Osteological differences between two species of Grammatorcynus 



SPHENOTIC 



FRONTAL 



LATERAL ETHMOID 



PROOTIC 



V — INTERCALAR 



BASIOCCIPITAL 



VOMER 



a PARASPHENOID 



FIRST VERTEBRA 



EXOCCIPITAL 



PTEROSPHENOID 



PTEROTIG 



Figure 8 



Ventral view of skulls in Grammatorcynus. (a) G. hilineatus, Scott Reef, Timor Sea, 453mm FL; (b) 

 G. bicarinatus. Western Australia, Exmouth Gulf, 765 mm FL. 



dorsally by the articular process. The process is larger 

 in G. bicarinatus, making the lachrymal wider (30-35% 

 of total bone length) than in G. hilineatus (27-30%). 

 The anterior portion has a small notch in it, much more 

 indistinct than the forked anterior region in Scorn- 

 beromorus (Fig. 10a). The posterior region is distinct- 



ly forked, with the ventral arm being wider and longer 

 than the dorsal arm. 



The second infraorbital connects to the forked pos- 

 terior region of the lachrymal. It is a small, elongate 

 bone. The third infraorbital is an elongate, tubular bone 

 that connects to the posterior portion of the second 



