REVIEW OF THE PARROTFISHES 25 



Chlorurus Swainson 



Chlorurus Swainson, Natural history and classification of fishes . . . , vol. 2, 

 p. 227, 1839 (genotype, designated as Scarus gibbus Riippell, pi. 20, fig. 2, 

 by Swain, Proc. Acad. Nat. Sci. Philadelphia, p. 274, 1882) ; also as Chlore- 

 gaster Swainson on p. 173 with no species listed). 



Bolbometo-pon J. L. B. Smith, Rhodes Univ. Ichthy. Bull. No. 1, p. 8, 1956 (type 

 species, Scarus mitricatus Cuvier and Valenciennes = Scarus gibbus Ruppell). 



Cetoscarus J. L. B. Smith, Rhodes Univ. Ichthy. Bull. No. 1, p. 16, 1956 (type 

 species, Scarus pulchellus Riippell). 



Ruppell (Atlas zu der Reise im Nordlichen Afrika . . . Fisciie 

 des rothen Meers, p. 81, pi. 20, fig. 2, 1828) described Scarus gibbus 

 from the Red Sea. It is very important to know what species was 

 meant, since S. gibbus the only species hsted is the genotype of Chlo- 

 rurus Swainson. Riippell's figure 2 shows a very characteristically 

 shaped parrotfish with at least 3 rows of scales on the cheek and 15 

 pectoral fin rays, these being equivalent to my count of ii,14 rays. 

 The angular profile of the head, especially the enlargement in front 

 of the orbits, and the straight profile of the snout leaves no doubt in 

 my mind that gibbus is what has been cm'rently passing under the 

 name of Scarus muricatus Cuvier and Valenciennes, as illustrated 

 by them (Histoire naturelle des poissons, vol. 14, pi. 402, 1839). The 

 two illustrations cited above are not accurate in regard to the arrange- 

 ment and number of scales on the cheek. The immature in alcohohc 

 preservation, up to a length of about 400 mm. in standard length 

 have pale spots arranged in vertical rows; beginning at about 300 mm., 

 these pale spots progressively disappear. 



Dr. J. L. B. Smith, in supporting his proposed new genera for this 

 group of species, did not attach suflicient importance to the "3 series 

 of scales on the cheek" and gave undue importance to the naked 

 preopercular "flange." Had he examined the pharyngeal mill of his 

 specimens he would not have confused "muricatus" with "microrhinus." 



Scarus gibbus Ruppell forms the basis of a very distinctive genus 

 of parrotfishes characterized as follows: The upper pharyngeal bones 

 have 3 rows of teeth on each side — two inner rows of large teeth and 

 an outer rudimentary row along the base of the middle row; the 

 lower pharyngeal plate has a concave dental surface as broad as long 

 or a ti-ifle longer than broad ; the teeth number 5 in each row and the 

 3 inner teeth are elongate laterally about 3 times as broad as long; 

 gill rakers oq the first arch vary from 4 to 9+ 11 to 15 totaling 15 to 

 23; there are three rows of scales on the cheek and 4 to 7 median 

 predorsal scales. 



The following key distinguishes the four species now known to b^ 

 referrable to this genus. 



