PIETSCH: OSTEOLOGY AND RELATIONSHIPS OF TETRABRACHIUM 



Ceratobranchial IV 



Ceratobranchial 



Epibranchial I -- 



Pharyngobranchial II 



Ceratobranchial V 



Epibranchial IV 



Figure 32. — Branchial arches oi Dihranchus atlanticus, MCZ 51257, 105 

 mm SL. The ventral portion of the branchial basket is shown m dorsal view, 

 the dorsal portion lepibranchials and pharyngobranchials) is folded back 

 and shown in ventral view. 



Pharyngobranchial III 



30). Epibranchial III is toothless in all antennari- 

 oids examined except in Dibranchus (Figure 32) 

 where this bone is associated with a single tooth 

 plate. 



Ceratobranchials I through IV are toothless in 

 Tetrabrachium , Antennarius, and Lophichthys 

 (Figures 11, 28, 29). In Brachionichthys (Figure 

 30), one to three tooth plates are present on 

 ceratobranchials I through III; in Chaunax (Fig- 

 ure 31), tooth plates are present on ceratobranchi- 

 als I through IV; in Dibranchus (Figure 32), tooth 

 plates are present on ceratobranchials I through 

 III (but also sometimes present on ceratobranchial 

 IV, see Bradbury 1967:408) (Table 2). 



In contrast to the separate, individual teeth 

 present on pharyngobranchial I and epibranchial 

 I of Lophichthys (Figure 29), those present on 

 epibranchial I and ceratobranchials I through IV 

 of Brachionichthys , Chaunax, and Dibranchus 

 (Figures 30-32) are born in clusters on individual 

 tooth plates. The tooth plates of Chaunax and 

 Dibranchus (Figures 31, 32) (and a number of 

 other ogcocephalid taxa, see Bradbury 1967) differ 

 from those of Brachionichthys (Figure 30) and 

 from those of all other lophiiforms in being 

 raised, pedicallike structures bearing a cluster of 

 numerous, tiny teeth at the apex (but see Brad- 



bury 1967, fig. 7, for other forms of gill teeth 

 in ogcocephalids). 



Ceratobranchial V is well toothed in all anten- 

 narioids examined. In Tetrabrachium, Anten- 

 narius, Lophichthys, and Brachionichthys (Fig- 

 ures 11, 28-30), this bone consists of a narrow, 

 toothed proximal portion and a tapering, cylin- 

 drical distal portion; m Chaunax (Figure 31) only 

 a triangular, toothed portion is present. In Di- 

 branchus (Figure 32), ceratobranchial V is greatly 

 enlarged, consisting of a finely toothed, expanded 

 proximal portion and a long, cylindrical distal 

 shaft. 



Hypobranchial I of Tetrabrachium, Antennar- 

 ius, Lophichthys , Brachionichthys , and Chaunax 

 (Figures 11, 28-31) and hypobranchial II of Brach- 

 ionichthys and Chaunax (Figures 30, 31) are 

 simple, rod-shaped bones. Hypobranchials II and 

 III of Tetrabrachium , Antennarius, and Lophich- 

 thys (Figures 11, 28, 29) are bifurcated proximally 

 (this feature is probably plesiomorphic for loph- 

 iiforms since a similar situation is present in all 

 batrachoidids examined). Hypobranchial III is 

 absent in Brachionichthys (Figure 30), but repre- 

 sented by a semicircular ossification in Chaunax 

 (Figure 31). There are no ossified hypobranchials 

 in the single specimen of Dibranchus examined 

 (Figure 32, Table 2). 



407 



