FILEFISHES ( MONACANTHIDAE ) OF THE WESTERN NORTH ATLANTIC 



71 



the specimens examined indicates that S. setifer 

 is more common around Cuba, Jamaica, other 

 islands of the West Indies, and in open waters of 

 the Gulf Stream or Florida Current. Apparently 

 it is a smaller species than S. hispidus, maturing 

 at a smaller body size. 



The relationship of this genus to Monacanthus 

 is discussed under the generic account of Mona- 

 canthus. Photomicrographs of the scale struc- 

 tures of Stephnnolepis (under the name of 

 Stefanolepis hispidus) were published by Sanzo 

 (1930, pi. Ill, figs. 32-35). 



The pelvic spine of Stephanolepis hispidus and 

 of S. setifer possesses barbs and is articulated with 

 the end of the barbed portion of the pelvic bone 

 that protrudes through the skin (fig. 5). It is 

 freely movable for a short distance (about 45°) 

 in an anteroposterior direction. 



The color patterns on sides, breast, and caudal 

 fin are of about equal value in separating the two 

 species; that is, the prominence of one of the 

 characters is usually accompanied by an equal 

 prominence of the other two. At sizes less than 

 about 22 mm. S.L. the species cannot be sepa- 

 rated on this basis as the patterns described below 

 are nearly always absent. From about 22 mm. 

 to about 27 mm. these patterns are often present. 

 Specimens between about 27 to 65 mm. normally 

 have good and distinguishable color patterns; the 

 pattern tends to become less distinguishing at 

 the larger sizes. Sides: S. setifer normally has 

 more rows of dashes arranged longitudinally, 

 giving a broken-lines effect, the dashes being 

 narrower and more sharply defined than the cor- 

 responding small bars and spots of S. hispidus; 

 and both species have smiilar broad, dusky bands 

 of varying intensity, that may be vertical or 

 oblique. Breast: Both species have the broad 

 dusky bands continuing onto the breasts, but in 

 addition, S. setifer has few to many small flecks 

 or spots, especially in the region ventral to and 

 anterior to the bases of the pectoral fins; these 

 flecks are entirely absent in S. hispidus. Caudal 

 fin: Botli species have two dark vertical bands 

 on the caudal fin, however, these bands are nar- 

 rower and usually much darker in S. setifer; the 

 first band in S. setifer is usually nmch darker tlian 

 the second, while in .S. hispidus both bands are 

 of about equal intensity and not very prominent. 



Stephanolepis hispidus (Linnaeus) 1758 

 (Figures 16, 17, 31, 32, and 33) 



The close relationship of this species to 

 Stephanolepis setifer has been discussed under the 

 account of the genus. 



Diagnostic characters. — Dorsal spines, 2. Dorsal 

 soft rays, 29 to 35; anal soft raj's, 30 to 35 (tables 7 

 and 10). Pectoral spine, 1; rudimentary at 

 larger sizes, pronounced in larvae (see fig. 16). 

 Pectoral soft ra3's, 12 to 14 (table 11). Pelvic 

 spine, large and movable (fig. 5). Gill sUt, nearly 

 vertical with respect to horizontal body axis (fig. 

 4). First dorsal spine, inserted over posterior 

 part of eye (fig. 4). No deep groove behind 

 dorsal spines. Body depth, 43.3 to 65.8% S.L. 

 (table 12; fig. 37). Head length, 29.5 to 41.4% 

 S.L. (table 13). Snout length, 14.4 to 27.5% 

 S.L. (table 14). Eye diameter, 6.9 to 17.1% S.L. 

 (table 15). Eye to dorsal spine distance, 7.3 to 

 17.1% S.L. (table 16). 



Specimens examined. — 3,539 of 5.6 to 211 mm. 

 S.L., from Georges Bank southward aU along the 

 Atlantic and Gulf coasts of the United States, off 

 Mexico and Brazil (fig. 40). 



It has been suggested (Fraser-Brunner, 1940: 

 p. 535) that the number of dorsal and anal fin rays 

 is greater in specimens from more northern local- 

 ities than from more southern localities. The 

 following values tend to indicate such a trend: 

 Eighty-seven specimens from the Gulf of 

 Mexico ranged from D 29-A 30 to D 34-A 34 with 

 a 26.2-percent mode at D 32-A 32 ; 267 specimens 

 from Georgia ranged from D 30-A 31 to D 34-A 33 

 with a 27.3-percent mode at D 32-A 32; 199 speci- 

 mens from North Carohna ranged from D 31-A 31 

 to D 35-A 35 with a 29.6-percent mode at D 33-A 

 33: but a smaller sample of 20 specimens from 

 Massachusetts ranged from D 32-A 32 to D 34-A 

 34 with a 40-percent mode of D 33-A 32, inter- 

 mediate between that of Georgia and North 

 Carolina. 



Sexual characters. — Two secondary sexual char- 

 acters develop on maturing males: the second soft 

 ray of the dorsal fin becomes very elongated, and 

 the spines of the scales on the sides of the caudal 

 peduncle become prolonged and form a patch of 

 bristles. The elongation of the second dorsal soft 



