no. 3647 PERCIFORM FISHES — GOSLINE 51 



maintains the usual percoid number of 15 branched rays, all other 

 families having a reduced number. 



In the caudal skeleton, the amount of fusion and/or loss varies 

 all the way from an almost basal percoid condition (Gosline, 1961b) 

 to a single bone (Makushok, 1958). The whole gamut is covered in 

 the notothenioid group and to a lesser extent in the others. At the 

 very base is Parapercis (Gosline, 1963, p. 95, fig. 6) with five hypurals 

 (counting as in Nybelin's 1963 system), one uroneural, three epurals, 

 and three hemal arches — all of these elements autogenous, i.e., 

 separate. In Trachinus (fig. 5b), at the base of the trachinoid-blennioid- 

 congrogadoid series, there are only 11 branched rays in the caudal 

 fin, and the two hypurals to the lower portion of the caudal fin have 

 become fused, but the other elements are as in Parapercis. In Bathy- 

 master, at the base of the zoarceoids, there are 14 branched rays; the 

 last hemal arch has fused to the lower hypurals to form a single 

 element supporting the bottom half of the caudal fin, but there are 

 still three separate upper hypurals, a uroneural, and three separate 

 epurals (fig. 5c) . All of the above fishes show less fusion in the caudal 

 skeleton than such percoids as Acanthoclinus and Opistognathus. 



The pathways of fusion seem to be about the same in the various 

 groups of Blennioidei. Thus, a general first stage seems to be a fusion 

 of the lower hypurals (Trachinus, fig. 5b) followed by an ankylosis 

 of these with the last hemal arch (Bathymaster, fig. 5c). This single 

 element fused to the lower part of the caudal fin remains separate 

 from the last centrum until after all of the upper hypurals and the 

 uroneural have fused to the urostyle. 



Vertebral column and ribs. — The basal percoids tend to have 

 a rather standardized vertebral column with 24 or 25 vertebrae, 10 

 abdominal and 14 or 15 caudal. This basal number always is exceeded 

 among the Blennioidei. The increase in the vertebral number occurs 

 first in the caudal section of the column; in the abdominal section, 

 members of the Parapercidae (Cantwell, 1964), Tripterygiidae 

 (Gosline, 1963), and Leptoscopidae (Regan, 1913) all are recorded 

 with 10 abdominal vertebrae. 



Ribs may be quite variable among the Blennioidei. Among the 

 flatter forms, pleural ribs may be lacking completely, as in Bembrops 

 and the leptoscopids. Pleural ribs also are lacking in the elongate 

 Pholidae (Makushok, 1958, p. 28). In the Uranoscopidae, pleural 

 and epipleural ribs both are attached to independent bony struts 

 that Starks (1923, p. 279) has called basipleurals. More frequently, 

 however, the usual percoid configuration of epipleural ribs from the 

 first, pleural ribs from the third vetebra, is present. From structure, 

 it is sometimes difficult (e.g., among congrogadoids) to distinguish 

 pleural from epipleural elements. 



