Bull. not. Hist. Mus. Lond. (Zool.) 63(1): 27-31 



Issued 26 June 1997 



Redescription of and lectotype designation for 

 Batistes macrolepis Boulenger, 1887, a senior 

 synonym of Canthidermis longirostris 

 Tortonese, 1954 and C. villosus Fedoryako, 

 1979 (Teleostei, Tetraodontiformes, Balistidae) 



ANTHONY C. GILL, e, 



Division of Lower Vertebrates, Department of Zoology, The Natural History Museum, Cromwell Road, London 

 SW7 5BD, United Kingdom 



JOHN E. RANDALL 



Ichthyology Division, Bishop Museum, P.O. Box 19000A, Honolulu, Hawaii 96817-0916, U.S.A. 



SYNOPSIS. Batistes macrolepis Boulenger, 1 887 is identified as a valid species of Canthidermis from an examination of the two 

 stuffed syntype specimens, 444 and 457 mm SL, from Muscat, Oman. The larger of these is designated lectotype. The species is 

 redescribed on the basis of the lectotype, paralectotype and two juvenile (30.5-32.0 mm SL) specimens from the Gulf of Aden, 

 and is shown to be a senior synonym of C. longirostris Tortonese, 1954 (described from a 365 mm SL specimen from the Dahlak 

 Islands, southern Red Sea) and C. villosus Fedoryako, 1979 (described from eight 55.5-177.3 mm SL juveniles from the Gulf of 

 Aden). Canthidermis macrolepis is distinguished from congeners in having fewer body scale rows (35—40 versus 39-58). 

 Juveniles of C. 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) 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). 



INTRODUCTION 



Boulenger (1887) described Batistes macrolepis from two large 

 (stated total length one foot 11 inches), dry specimens from Muscat, 

 Oman. With the exception of two books [Randall ( 1 995 ) and Debelius 

 (1996)] that give accounts for B. macrolepis resulting from the 

 present research, the species has not been referred to subsequently. 

 Boulenger gave the following characters for the species: dorsal-fin 

 rays III + 26; anal-fin rays 23; a groove in front of eye; no enlarged 

 scales behind the gill opening; no spines on the tail; falciform dorsal 

 and anal fins; and a strongly notched caudal fin. The absence of 

 enlarged scales behind the gill opening is unique among Indo- 

 Pacific balistids to the genera Canthidermis Swainson, Xanthichthys 

 Kaup and Xenobalistes Matsuura (Matsuura, 1980, 1981; Smith & 

 Heemstra, 1986). There are two stuffed specimens labelled as B. 

 macrolepis in the Natural History Museum, London, which we 

 believe to be the syntypes. One (BMNH 1887.11.11.334; Fig. 1) 

 measures 457 mm SL and is mounted on an exhibition stand, 

 whereas the other (BMNH 1 887. 1 1 . 1 1 .335) measures 444 mm SL. 

 The specimens have a terminal mouth with uneven, notched teeth, a 

 deep groove before the eye, and a relatively well-developed third 

 dorsal spine extending above the dorsal edge of the body, and lack 

 enlarged scales behind the gill opening and longitudinal grooves on 

 the cheek; this combination of characters is unique among balistids 

 to species of the genus Canthidermis (Matsuura, 1980). 



Recent authors (e.g., Berry & Baldwin, 1966; Matsuura, 1980; 

 Smith & Heemstra, 1986) have recognised only two valid species of 

 Canthidermis, the cosmopolitan C. maculatus (Bloch) and the At- 

 lantic C. sufflamen (Mitchill). However, Fedoryako (1979) recognised 

 five species of Canthidermis in the most recent review of the genus: 



C. maculatus, C. sufflamen, C willughbeii (Lay & Bennett) (from 

 the eastern Pacific), C. rotundatus (Proce) (from the Indo-West 

 Pacific), and C. villosus, which Fedoryako described as a new 

 species. 



Fedoryako (1979) described C. villosus from eight pelagic juve- 

 niles (55.5-177.3 mm SL) from the Gulf of Aden. He distinguished 

 it from juvenile congeners in having relatively long, branched, 

 fleshy outgrowths on body and head scales (versus fleshy outgrowths 

 short and unbranched or absent), large, pale spots on head and body 

 forming a network pattern (versus pale spots absent or not forming 

 a network pattern), and 36-40 (versus 39-57) transverse rows of 

 scales (= body scale rows). We located two additional juvenile 

 specimens of the species in the Natural History Museum, London, 

 (BMNH 1939.5.24.1849-1850) that had been surface dipnetted in 

 the Gulf of Aden by the 1933-34 John Murray Expedition (Station 

 25) on the 10th of October, 1933. These specimens had been 

 identified as Canthidermis sp. and briefly described in Norman's 

 (1939) report of fishes of the 1933-34 John Murray Expedition. 

 Adult specimens of C. villosus have not been described. However, 

 the fin-ray and scale counts of the two adult syntypes of Balistes 

 macrolepis agree closely with those of C villosus (Table 1 ), and we 

 conclude that the two nominal species are conspecific. Balistes 

 macrolepis Boulenger, 1 887 is therefore a senior synonym of 

 Canthidermis villosus Fedoryako, 1979. 



The second author searched his photographic library and found 

 four photographs of individuals that we believe to be conspecific 

 with the syntypes of B. macrolepis. One photograph taken at Fahl 

 Island off Muscat in the Gulf of Oman by J. P. Hoover shows a 

 nesting pair (Fig. 2). Two others by H. Debelius are of specimens 

 from Oman, one a natural underwater photograph, the other of an 



© The Natural History Museum. 1997 



