REVIEW OF THE PARROTFISHES 



9 



observed that in the Sparisomatinae, the number of median predorsal 

 scales are constantly 4 or 5, whereas in the Scarinae the number is 

 variably 3 to 8. This variability appears to progress in two directions, 

 reduction to 3 in Ypsiscarus and an increase to as many as 8 in certain 

 species of the subgenus Hemistoma. 



5. The number of rows of scales on the cheek in the Sparisomatinae 

 is constantly one, whereas in the Scarinae it is variable from 2 to 4. 

 It would appear that the median predorsal scales number 4 and that 

 a single row of scales on the cheek represent the more generalized 

 condition in scarid fishes. An increase in the number of rows of 

 scales on the cheek appears to represent a specialized trend in the 

 genus Scarus. 



6. The branched pectoral fin rays in the Sparisomatinae number 

 11, whereas in the Scarinae they are normally 12 to 15. It would 

 appear from the variability in number of these rays in the Scarinae 

 that they are of lesser evolutionary importance, but the general 

 direction of specialization indicates an increase in the niunber of 

 branched pectoral rays. In the genus Scarus an increase in the 

 number of pectoral rays agrees generally with the increase in number 

 of scales in the ventral row on the cheek. This suggests a more 

 specialized condition for those species with increased numbers. 



In figure 1, each character given under the " CryptotomiLS-like 

 labrid stock" occurs in all ancestral stocks of the genus, up through 

 each phyletic line unless differently indicated under each stock or 

 genus. For example "pt. 3" (upper pharyngeal teeth in three rows) 

 occurs for all "stocks" and genera through the Scarus-like phyletic 

 lines but is gradually reduced to "pt. 1" (upper pharyngeal teeth in 

 one row) in Scarops at the end of this phyletic line. 



Geographical distribution 



So much misidentification is prevalent for parrotfishes in the 

 ichthyological literature that at present the geographical distribution 

 of each species of parrotfish cannot be worked out in detail. Many 



FlGtJRE 1.- 



ff, gill membranes with free fold 



across isthmus 

 gf, gill rakers few and coarse 



gm, gill rakers several, moderately- 



coarse 

 gn, gill rakers very numerous, fine 



ms 4, median predorsal scales 4 



ms 3-9, median predorsal scales, 3, 4, S, 



etc. 

 p. 11, branched pectoral rays 11 



p. 12-17, branched pectoral rays 12 to 17 



-Continued 



pt 1, upper pharyngeal teeth in one row 



pt 2, upper pharyngeal teeth in two 



rows 

 pt 3, upper pharyngeal teeth in three 



rows 

 tl, tip of lower jaw fits over that of 



upper jaw 

 to, tips of jaws oppose each other 



tu, tip of upper jaw fits over that of 



lower jaw 



