Munroe Western Atlantic tonguefishes of the Symphurus plagusia complex 



267 



in the posterior portions of sexually mature males). In 

 contrast, S. caribbecmus has numerous well-developed 

 erossbands and vertical fins with an alternating series 

 of blotches and unpigmented areas in individuals of 

 both sexes. Symphurus caribbeanus also has a more 

 pointed snout with only a narrow space between the 

 upper eye and dorsal fin base (versus a square snout 

 with a space between the upper eye and the dorsal fin 

 base usually greater than twice the eye diameter in 

 S. civitatium; compare Figures 4b and 4e). 



Despite some overlap in certain meristic values, S. 

 civitatium and S. tessellatus are quite distinctive. The 

 easiest way to distinguish these species is that S. civi- 

 tatium has a well-developed fleshy ridge on the ocular- 

 side lower jaw (absent in S. tessellatus; compare Fig- 

 ures 4b and 4c), lacks a black spot on the ocular-side 

 opercle, and, when present on the body, erossbands are 

 faint and narrow, whereas S. tessellatus has a bold pat- 

 tern of wide erossbands and a well-developed black 

 opercular spot. Other distinctions between these spe- 

 cies include the absence of scales on the blind sides of 

 the dorsal and anal fin rays of S. civitatium (present 

 in 5. tessellatus larger than about 60 mm SL), fewer 

 vertebrae (total vertebrae 47-49 vs. 50-53 in S. tessel- 

 latus), and modally lower meristic features: dorsal fin 

 rays 86-93 vs. 91-102 (usually 93-101) in 5. tessellatus; 

 anal fin rays 70-78 vs. 77-86; scales in a longitudinal 

 series 66-83 vs. 81-96. 



Some meristic values of S. civitatium overlap those 

 of 11 other species of Atlantic tonguefishes. Symphu- 

 rus civitatium occurs sympatrically with S. diome- 

 deanus and S. plagiusa and may be collected with these 

 species. The suggestion by Walls (1976:390) to syn- 

 onymize 5. civitatium with S. plagiusa, based on par- 

 tial overlaps in meristic features, pigmentation, and 

 ecological co-occurrence, is not supported by results of 

 this study. Symphurus civitatium differs from both 

 these species primarily in caudal-fin-ray count (12 vs. 

 10 in the others) and by notable differences in pigmen- 

 tation patterns. Symphurus diomedeanus usually has 

 a series of black spots on posterior rays of the dorsal 

 and anal fins and a well-developed pupillary operculum 

 (both characters absent in S. civitatium). Symphurus 

 civitatium can be distinguished from S. plagiusa in that 

 S. plagiusa usually has a well-developed black spot on 

 the outer surface of the ocular-side opercle (absent 

 altogether or only a diffuse blotch resulting from pig- 

 ment from the inner opercular lining showing to the 

 outside in S. civitatium), and inner opercular linings 

 on both sides are heavily pigmented (only the ocular- 

 side opercular lining is pigmented in S. civitatium). 

 Symphurus plagiusa has larger eyes (83-126 HL) that 

 are usually equal in position (versus smaller eyes 

 70-110 HL, which are slightly subequal in position in 

 S. civitatium). Also, the jaws reach only as far pos- 



teriorly as a vertical through the mid-eye region in S. 

 plagiusa, while in S. civitatium the jaws reach a ver- 

 tical through the rear margin of the pupil, the rear 

 margin of the eye, or may even extend slightly beyond 

 a vertical equal with the posterior margin of the lower 

 eye in S. civitatium. In larger S. plagiusa, there are 

 4-8 ctenoid scales on the blind sides of the dorsal and 

 anal fin rays (absent or at most only 1-2 scales along 

 bases of fin rays in S. civitatium). 



Symphurus civitatium is not easily confused with 

 other Atlantic species (S. kyaropterygium, S. trewava- 

 sae, S. normani, S. piger, S. nigrescens, S. pusillus, 

 S. lubbocki, and S. reticulatus) with which it overlaps 

 in some meristic features. Symphurus civitatium. dif- 

 fers from all of these in ID pattern (1-4-3 versus other 

 patterns: 1-4-2 in S. kyaropterygium; 1-3-3 in S. trewa- 

 vasae and S. normani; 1-3-2 in S. piger, S. nigrescens, 

 S. pusillus, S. reticulatus, andS. lubbocki). In addition 

 to differences in ID pattern, S. civitatium differs from 

 the South Atlantic S. kyaropterygium in caudal-fin-ray 

 number (12 vs. 10) and in lacking the pupillary oper- 

 culum and darkly-pigmented blotch on the caudal ex- 

 tremity both present in S. kyaropterygium. Symphurus 

 civitatium differs from the South Atlantic S. trewava- 

 sae principally in caudal-fin-ray count (12 vs. 10) and 

 its smaller eye (70-110 HL vs. 114-162 HL in S. tre- 

 wavasae). The eastern Atlantic S. normani possesses 

 scales on the blind sides of the dorsal and anal fin rays, 

 has a spotted peritoneum, and pepper-dot pigmenta- 

 tion on the blind side of the body (all absent in S. 

 civitatium). Symphurus civitatium differs from the 

 species with a 1-3-2 ID pattern (except S. lubbocki and 

 5. reticulatus) in lacking a black peritoneum. Sym- 

 phurus civitatium is further distinguished from S. lub- 

 bocki and S. reticulatus in having a fleshy ridge on the 

 ocular-side lower jaw (absent in these others), in lack- 

 ing complete dentition on ocular-side jaws (ocular-side 

 jaws without dentition, or with only a partial row of 

 teeth, versus ocular-side jaws with complete dentition 

 in S. lubbocki and S. reticulatus), by its much larger 

 size (152 vs. <50mm SL), and by differences in pigmen- 

 tation (dark-brown body with erossbands and uniform- 

 ly-pigmented fins versus light-brown or yellowish body 

 with incomplete erossbands in S. lubbocki and dark 

 chocolate-brown body with X- and Y-shaped markings 

 and vertical fins with alternating series of blotches and 

 unpigmented areas in S. reticulatus). 



Meristic values of S. civitatium overlap those of five 

 eastern Pacific species possessing either a 1-4-3 or 1-5-3 

 ID pattern, including S. atricaudus, S. melanurus, 

 S. williamsi, S.fasciolaris, and 5. melasmatotheca. Of 

 these species, S. civitatium is most similar to S. mela- 

 nurus in that both possess a fleshy ridge on the ocular- 

 side lower jaw, and in both the first dorsal fin ray 

 reaches the vertical equal with or anterior to the 



