click for previous page 3890 Bony Fishes CYNOGLOSSIDAE Tonguesoles by T.A. Munroe iagnostic characters: Lance- or tongue-shaped flatfishes with eyes on left side of body (size to D40 cm); body highly compressed and tapering to a point posteriorly. Eyes small and usually close together. Mouth small, subterminal, asymmetrical; reaching posteriorly to point between verticals at anterior and posterior margins of lower eye or slightly posterior to lower eye; jaws moderately curved on eyed side and notably on blind side; teeth minute and usually only on blind-side jaws; lips fringed with labial papillae in Paraplagusia. Rostral hook usually present below mouth. Posterior margin of preopercle strongly attached to opercle, without free margin and covered with skin and scales. No spiny rays in dorsal, anal, and pelvic fins; dorsal fin reaching far forward onto head; dorsal and anal fins confluent with caudal fin; pectoral fins absent; usually only right pelvic fin present. Scales small, ctenoid or cycloid (smooth). Lateral lines variable; none present in Symphurus; 1 to 3 on eyed side and 0 to 2 on blind side in Cynoglossus and Paraplagusia. Species of Symphurus with only a single proximal dorsal-fin pterygiophore inserted into first interneural space; species of Cynoglossus and Paraplagusia with several pterygiophores inserted into first interneural space. Colour: colour pattern may vary within a species; eyed side usually uniformly brownish or greyish, often variably marked with patches, spots, or cross bands on body, and some species with blotches and spots on fins; most species uniformly whitish or yellowish on blind side, others with small indistinct cloudy patches or darker spots. eyes on left scales between middle and side of head upper lateral lines lateral lines no fin spines origin of dorsal fin anterior to eyes dorsal, anal, and caudal fins confluent rostral hook usually present below mouth pectoral fins preopercular margin always absent embedded in skin Habitat, biology, and fisheries: Small to medium-sized benthic fishes, commonly found on muddy bottoms and other substrates, from tidepools to deep waters on outer continental shelf and upper continental slope (to about 1 500 m). Tonguesoles are of limited economic importance with catch statistics for individual species not usually available. From 1990 to 1995, the FAO Yearbook of Fishery Statistics reports a yearly catch of around 22 700 to 28 600 t of Cynoglossidae from the Western Central Pacific. Marketed fresh, frozen, and also dried-salted. dorsal and anal fins origin of dorsal fin attached or not attached anterior to eyes Similar families occurring in the area to caudal fin Soleidae: also with small mouth, preopercular margin embedded in skin, no fin spines, dorsal-fin orgin far forward on head, and some species with dorsal and anal fins joined to caudal fin, but eyes on right side of body (on left side in Cynoglossidae). Also, always with 2 pelvic fins, and pectoral fins sometimes present. no fin spines eyes on right pectoral fins sometimes absent side of head Soleidae Pleuronectiformes: Cynoglossidae 3891 anterior rays of dorsal dorsal-fin origin and anal fins spinous posterior to eyes Psettodidae: mouth large, with large teeth; dorsal and mouth anal fins separate from caudal fin; dorsal fin not large, with extending forward on head; anterior dorsal- and anal-fin large teeth rays spinous; margin of preopercle free and distinct, not embedded in skin. Pleuronectidae, Bothidae, Paralichthyidae: also with dorsal-fin origin far forward on head and no spines in fins, but dorsal and anal fins separate from caudal fin, and margin of preopercle free and distinct, not eyes on left or embedded in skin. right side of head Psettodidae margin of preopercle free eyes on left side eyes on right side dorsal and anal fins not attached margin of to caudal fin preopercle free Bothidae eyes on left side margin of Paralichtyidae Pleuronectidae margin of preopercle preopercle free distinct, not covered with skin and scales Identification note 1. Midlateral-line scales are counted from the vertical lateral-line branch on the head (i.e. branch between midlateral and dorsolateral line) to the base of the caudal fin. 2. Since the caudal fin is confluent with both the dorsal and anal fins, caudal-fin rays are best counted from the blind side of the fish using transmitted light. In order to observe the point where the caudal-fin rays articulate to the epural and hypural bones, it may be necessary to remove some scales and skin at the caudal-fin base. Key to the species of Cynoglossidae occurring in the area 1a. No lateral line on eyed side of body; mouth terminal, snout not hooked over mouth (Fig. 1) . Symphurus (primarily small-sized deep-water species with no commercial importance) 1b. Two or 3 lateral lines on eyed side of body; mouth inferior, front part of snout produced into rostral hook and covering mouth (Fig. 2) ............................® 2 rostral hook 2-3 lateral lines no lateral line Fig. 1 Symphurus Fig. 2 3892 Bony Fishes 2a. Lips on eyed side of head not fringed with labial papillae ...................(Cynoglossus) ® 3 2b. Lips on eyed side of head distinctly fringed with labial papillae (Fig. 3) ...........(Paraplagusia) ® 23 3a. Caudal fin with 8 or 9 rays (caudal-fin rays best fringed lips observed from blind side using transmitted light) .....® 4 3b. Caudal fin with more than 9 rays ..............® 9 4a. Two lateral lines on eyed side of body ...........® 5 4b. Three lateral lines on eyed side of body ..........® 6 Fig. 3 Paraplagusia 5a. Scales ctenoid on both sides of body; scales between lateral lines more numerous (10 to 13); 2 rounded, conspicuously pigmented spots on posterior one-third of eyed side of body . Cynoglossus maculipinnis 5b. Scales ctenoid on eyed side of body, cycloid on blind side; scales between lateral lines fewer (8); no obviously pigmented spots on eyed side of body . Cynoglossus ogilbyi (not yet reported from the area) upper eye advanced upper eye not advanced 6a. Upper eye (migratory eye) much in advance of fixed eye (Fig. 4a) . Cynoglossus microlepis 6b. Upper eye (migratory eye) not in advance of fixed eye (Fig. 4b) .......® 7 7a. Posterior region of peritoneum darkly pigmented (usually show- ing through abdomen on both a) b) sides of body) . Cynoglossus mccullochi Fig. 4 7b. Peritoneum unpigmented .........® 8 8a. Body comparatively slender (19 to 23% standard length); maxilla extending posteriorly beyond fixed eye; corner of mouth nearer to branchial opening than to tip of snout (Fig. 5) . Cynoglossus gracilis (not yet reported from the area) 8b. Body comparatively deep (23 to 28% standard length); maxilla extending only to point equal with verticals through middle and posterior margin of fixed eye; corner of mouth nearer to tip of snout than to branchial opening (Fig. 6) . Cynoglossus abbreviatus (not yet reported from the area) Fig. 5 Cynoglossus gracilis Fig. 6 Cynoglossus abbreviatus 9a. Caudal fin usually with 10 rays ...................................® 10 9b. Caudal fin usually with 12 rays ...................................® 22 10a. Only 2 lateral lines (dorsal and medial) on eyed side of body ...................® 11 10b. Three lateral lines (dorsal, medial, and ventral) on eyed side of body ..............® 17 Pleuronectiformes: Cynoglossidae 3893 11a. Eyes small, pedunculate (Fig. 7) . Cynoglossus monopus 11b. Eyes not pedunculate ........................................® 12 12a. Eyes contiguous, or nearly so (Fig. 8a) . Cynoglossus kopsi 12b. Eyes distinctly separate (Fig. 8b) ..................................® 13 eyes pedunculate separate eyes eyes contiguous a) b) Fig. 7 Cynoglossus monopus Fig. 8 13a. Scales ctenoid on both sides of body ................................® 14 13b. Scales ctenoid on eyed side of body, and cycloid on blind side ..................® 16 14a. Rostral hook comparatively short, extending only to point between verticals through anterior nostril and just anterior to anterior margin of fixed eye ..................® 15 14b. Rostral hook comparatively long, extending at least to vertical through middle of fixed eye . Cynoglossus lida 15a. Dorsolateral line usually undulating; no dark blotches or irregular cross bands on body; eyed-side lower jaw with crenulate fleshy ridge comprised of several folds, or jaw with a single broadly triangular-shaped fleshy ridge (Fig. 9) . Cynoglossus cynoglossus 15b. Dorsolateral line slightly undulating; eyed side with dark blotches forming irregular cross bands; eyed-side lower jaw with low, broadly rounded fleshy ridge (Fig. 10) . Cynoglossus puncticeps dorsolateral line undulating irregular cross bands Fig. 9 Cynoglossus cynoglossus Fig. 10 Cynoglossus puncticeps 16a. Midlateral-line scales numerous (90 to 101); 11 or 12 scales between lateral lines .. Cynoglossus lingua 16b. Midlateral-line scales fewer (56 to 70); 7 to 9 scales between lateral lines . Cynoglossus arel 17a. Midlateral-line scales less than 100 ................................® 18 17b. Midlateral-line scales 100 or greater ................................® 19 18a. Blind side with ctenoid scales, except head region with cycloid or weakly ctenoid scales; only 17 or 18 scales between dorsolateral and midlateral lines . Cynoglossus feldmanni 18b. Blind side of body and head region with ctenoid scales throughout; about 24 scales between dorsolateral and midlateral lines . Cynoglossus waandersi 19a. One nostril on eyed side of head . Cynoglossus macrophthalmus 19b. Two nostrils on eyed side of head .................................®