FISHERY BULLETIN: VOL. 80, NO. 1 



Moser et al. (1977) and Sumida et al. (1979), with 

 slight modification because of the peculiarities of 

 bothid development. 



Preflexion stage = notochord is straight. 



Early caudal formation = a substage of preflex- 

 ion in which the notochord is still straight, but 

 the caudal fin has begun to form. 



Flexion stage = notochord is turning upward. 

 There are three substages: Early flexion = 

 notochord is slightly flexed; midflexion = noto- 

 chord is S-shaped and flexed about 30°-60°; 

 late flexion = notochord is turned up and is no 

 longer S-shaped but is not yet in final position. 



Postflexion stage = notochord is in final position, 

 but transformation is not complete. 



Transforming larvae = those in which dorsal mi- 

 gration of the right eye can be detected with 

 low magnification. The period of transforma- 

 tion is divided into thirds, depending on the 

 position of the right eye. 



Juveniles = those specimens in which the right 

 eye has reached its final position on the left side 

 of the head and in which all fin rays have 

 formed. Reported size ranges at transforma- 

 tion are based on available specimens and 

 might not encompass the full possible size 

 ranges. Environmental stimuli inducing 

 transformation may be encountered at differ- 

 ent sizes. 



Terminology of components of the caudal skel- 

 eton follows Amaoka (1969), except as noted. The 

 caudal fin formula was described by Gutherz 

 (1971) as the number of caudal rays supported by 

 each caudal element, dorsal to ventral. 



Gutherz (1971) described certain cranial 

 spines of Cyclopsetta fimbriata larvae as origi- 

 nating from the sphenotic bones. Futch and Hoff 

 (1971) described similar spines of Syacium 

 papillosum larvae as originating from the fron- 

 tal bones. In the Citharichthys and Etropus 

 larvae I have examined, similar spines are at the 

 suture between frontal and sphenotic bones. The 

 origin of these could not be determined with cer- 

 tainty, and therefore they are called "frontal- 

 sphenotic" spines. 



For the larvae described here, the first elon- 

 gate dorsal ray is actually the second ray of that 

 fin. 



Larval Identification 



Four developmental series were assembled, 



primarily on the basis of similar meristics, 

 shape, and pigmentation. Transforming larvae 

 and juveniles were identified first by the pres- 

 ence of known adult characters. Additional lar- 

 val characters observed in those specimens were 

 then used to aid in identification of the smaller 

 specimens. 



Because all transformed specimens were sinis- 

 tral and the right eye of all transforming speci- 

 mens was migrating, it was decided that the four 

 larval series belonged to one or more of the flat- 

 fish families Bothidae, Scophthalmidae, or Cy- 

 noglossidae. Morphological characters exhibited 

 in the larval series and shared by larvae of these 

 three families are lateral compression, deep 

 head, deep abdomen, and looped gut, and in early 

 larvae a raised and rounded dorsal profile of the 

 head and slender caudal region. Only one scoph- 

 thalmid species, Scophthalmus aquosus, is 

 known from the western North Atlantic 

 (Gutherz 1967; Hensley 1977). The distinctive 

 rhomboid shape, long-based pelvic fins, and 

 dense pigmentation of S. aquosus larvae were 

 lacking in my series of larvae. The small eyes, 

 small head, and confluent dorsal, caudal, and 

 anal fins of cynoglossids were also lacking. In 

 addition, cynoglossids from this region have 

 fewer caudal (usually 9-14) and pelvic (usually 4 

 left, right) rays than the specimens in my se- 

 ries. Therefore, Scophthalmidae and Cynoglossi- 

 dae were eliminated from consideration. 



Gutherz (1971) summarized known characters 

 most useful for identifying bothid larvae. Futch 

 (1977) summarized subfamilial larval charac- 

 ters and tentatively recognized two subfamilies, 

 Paralichthyinae and Bothinae. The following 

 discussion is limited to western North Atlantic 

 species. Four paralichthyine genera.— Citharich- 

 thys, Cyclopsetta, Etropus, and Syacium — have a 

 similar combination of transitory (larval) and 

 permanent characters that distinguish them 

 from other bothid genera. These include: 1) adult 

 caudal fin ray formula of 4-5-4-4; 2) placement 

 of the left pelvic fin on the ventral midline and 

 the right above the ventral midline, both origi- 

 nating behind the cleithra (Gutherz 1971); 3) the 

 same basic larval shape; 4) similar larval pig- 

 mentation—on the gas bladder, in dorsal and 

 anal lines, and in the caudal region; 5) larval pre- 

 opercular spines (at least in Citharichthys cor- 

 nutus, C gymnorhinus, C. spilopterus, Cyclop- 

 setta fimbriata, C. chittendeni, Etropus crossotus, 

 E. microstomus, and Syacium papillosum); 6) 

 larval frontal-sphenotic spines (at least Cith- 



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