FISHERY BULLETIN: VOL. 79, NO. 3 



Parietal 



Supraethmoid 



Vomer 



Posttemporal 



Epiotic 



lateral ethmoid 



Supraoccipital 



Figure 19. — Dorsal view of cranium of Dihranchiis atlan- 

 tim.s, MCZ 51257, 105 mm SL. 



Pterotic 



Sphenotic 



Dibranchus (Figures 21, 24, 25), but absent in 

 Tetrabrachium, Lophichthys, and Brachionich- 

 thys (Figures 9, 22, 23). The triradiate ecto- 

 pterygoid of Antennarius , Tetrabrachium, and 

 Lophichthys (T-shaped in Tetrabrachium and 

 Antennarius, Figures 9, 21, but Y-shaped in 

 Lophichthys, Figure 22) overlaps the medial sur- 

 face of the metapterygoid dorsally; in Chaunax 

 and Dibranchus the ectopterygoid is crescent- 

 shaped and makes no contact w^ith the metaptery- 

 goid. An ectopterygoid is absent in the larger (69 

 mm SL) specimen of Brachionichthys examined 

 (Figure 23A) but represented by a small, weakly 

 ossified remnant in the smaller specimen (42 mm 

 SL) (Figure 23B). 



The palatine is well toothed in Antennarius, 

 Lophichthys, and Chaunax, but toothless in 

 Tetrabrachium and in the single cleared and 

 stained specimen o{ Dibranchus examined (pala- 

 tine teeth are present in some ogcocephalid genera 

 and sometimes in Dibranchus; Bradbury 1967: 

 409). In the absence of a mesopterygoid and 

 reduced (or absent) ectopterygoid, the toothless 

 palatine bone of Brachionichthys is widely sep- 

 arated from the suspensorium (Figure 23). 



Hyoid arch (Figures 9, 10, 21-27). — In Tetra- 

 brachium and Antennarius (Figures 9, 21) the 

 dorsal head of the quadrate is relatively narrow, 

 somewhat less than the width of the ventral head 

 of the metapterygoid. In contrast, the quadrate 



of Lophichthys, Brachionichthys , Chaunax, and 

 Dibranchus (Figures 22-25) is broad, making a 

 much broader contact with an expanded meta- 

 pterygoid. In Dibranchus the quadrate is excep- 

 tionally broad, the anterior half of the dorsal 

 margin coming into contact with the mesoptery- 

 goid (Figure 25). 



The interhyal o{ Antennarius , Lophichthys , and 

 Brachionichthys is similar to that of Tetrabrach- 

 ium (but in contrast to that of Chaunax and 

 Dibranchus; Figures 24, 25) in having a promi- 

 nent, medial, posterolaterals directed process 

 that vvTaps around the posterior margin of the 

 respective preopercle when the interhyal rotates 

 upward (Figure 26). This contact between the 

 interhyal and preopercle limits the dorsal rotation 

 of the interhyal and, in turn, limits the extent of 

 abduction of the lower jaw via ligamentous con- 

 nections with the respective interopercle. 



In shape and relative proportions, the branchi- 

 ostegal rays of Antennarius, Lophichthys, and 

 Brachionichthys are similar to those of Tetra- 

 brachium; Brachionichthys , however, has lost the 

 anteriormost element in this series (Table 2). In 

 Chaunax and Dibranchus (Figure 27) the poste- 

 riormost branchiostegal ray is greatly enlarged, 

 becoming ankylosed to the ventromedial margin 

 of the subopercle in the later genus. 



A small basihyal is present in Antennarius, 

 Tetrabrachium, Lophichthys, and Chaunax, but 

 absent in Brachionichthys and Dibranchus. 



400 



