28 



A.C. GILL AND J.E. RANDALL 



aquarium specimen in the Muscat Aquarium; both photographs 

 were reproduced in Debelius (1993: 298). The final photograph, 

 taken by the second author, is of a. ca. 300 mm total length specimen 

 in the Zubayr Islands, southern Red Sea (reproduced in Randall, 

 1995: fig. 1 108). The localities forthese photographs and specimens 

 suggest that the species might be restricted to the northwestern 

 Indian Ocean and Red Sea. We searched literature on Canthidermis 

 from the area and found two additional references. Tortonese ( 1 954) 

 described C. longirostris from the Dahlak Islands, southern Red Sea, 

 and Dor (1984) recorded C. maculatus from the Red Sea. However, 

 Dor's record was based on Tortonese's specimen of C. longirostris, 

 and followed Berry & Baldwin's (1966) synonymy of the two 

 species; apparently, Fedoryako (1979) overlooked C. longirostris in 

 his review of the genus. Examination of Tortonese's description and 

 figure of C. longirostris revealed that it is not referable to C. 

 maculatus, rather it is a second junior synonym of B. macrolepis. 



MATERIALS AND METHODS 



Pectoral-fin ray counts include the uppermost, rudimentary ray. 

 Other methods of counting and measuring follow Matsuura (1980). 

 Institutional codes follow Leviton et al. (1985). 



SYSTEMATIC ACCOUNT 



Canthidermis macrolepis (Boulenger, 1887) 

 Figures 1-3; Tables 1-2 



Balistes macrolepis Boulenger, 1887: 666 (type locality: Muscat; 

 lectotype: BMNH 1887.1 1.1 1.334, 457 mm SL, designated be- 

 low). 



Canthidermis sp. - Norman, 1939: 109 (Gulf of Aden). 



Canthidermis longirostris Tortonese, 1954: 77, fig. 1 (type locality: 

 Dahlak Is, Red Sea; holotype: MZGZ 20162, 365 mm SL). 



Canthidermis villosus Fedoryako, 1979: 985, fig. IB (type locality: 

 12°29'N 44°23'E, Gulf of Aden; holotype: MGY P-15097, 55.5 

 mm SL). - Fedoryako, 1981: 21, fig. lc (English translation of 

 original description). 



Canthidermis maculatus [non Balistes maculatus, Bloch 1786], - 

 Berry & Baldwin, 1966: 463 (synonymy with C. longirostris). - 

 Dor, 1984: 275 (Red Sea; based on holotype of C. longirostris). - 

 Debelius, 1993: 298 (colour photographs of specimens from 

 Oman). 



Canthidermis macrolepis. - Randall, 1995: 393, fig. 1 108 (descrip- 

 tion, synonymy and distribution based on present study; colour 

 photograph). - Debelius, 1 996: 298 (colour photographs of speci- 

 mens from Oman). 



DIAGNOSIS. Canthidermis macrolepis is readily distinguished from 

 congeners in having fewer body scale rows (35-40 versus 39-58). 

 As noted by Fedoryako (1979, 1981; see above), juveniles of 

 Canthidermis macrolepis are readily distinguished from those of 

 congeners by scale morphology (relatively long, branched, fleshy 

 outgrowths present on body and head scales versus fleshy outgrowths 

 short and unbranched or absent; Fedoryako, loc. cit.: fig. 1C cf. fig. 

 1A,B) and coloration (pale spots on head and body large and 

 forming a network pattern versus pale spots absent or small and not 

 forming a network pattern). 



Description, (based on data from BMNH specimens; see Tables 

 1,2 for counts and measurements of individual specimens, and for 

 data from Tortonese's and Fedoryako's respective descriptions of C. 

 longirostris and C. villosus) 



Dorsal-fin rays III + 25-26, all segmented rays branched except 

 for the first 1-2; anal-fin rays 22-23, all rays branched except for the 

 first; pectoral-fin rays 15-16, the upper ray a rudiment, and the 

 second from uppermost unbranched; body scale rows 35-39; head 

 scale rows 25-29; vertebrae 7+11 (from radiographs of BMNH 

 1939.5.24.1849-1850 only); gill rakers 8-10 + 20-22 = 30, the 



Fig. 1 Canthidermis macrolepis, BMNH 1887.1 1.1 1.334, lectotype, 457 mm SL, Muscat, Oman (photograph by P. Hurst). 



