AHLSTROM ET AL.: PLEURONECTIFORMES 



649 



Table 173. Extended. 



Soleidae. Cynoglossidae. the pleuronectid subfamily Rhombo- 

 soleinae, and Mancopsetia. previously considered a bothid (Fig. 

 341. Table 172). Eggs have been described for about a dozen 

 kinds of soleids ranging in size from 0.64-1.75 mm. Eggs are 

 round, or occasionally slightly off-round. Oil globules are usually 

 numerous but vary in number, size and distribution within the 

 yolk. They can be highly clumped, as in Solea solea. or scattered 

 throughout the yolk, as in Microchirus variegalus. In eggs of the 

 latter, oil globules were observed to range in size from 0.015- 

 0.12 mm. whereas they are much smaller and more uniform in 

 size in Solea solea or Pegusa lascans. Eggs of the two achirine 

 soleids described from the western Atlantic have a relatively 

 low number of oil globules. Perivitelline space is narrow to 

 negligible in soleid eggs. The yolk is peripherally segmented in 

 eggs of the four species known from the eastern North Atlantic. 

 Yolk is more completely segmented in the egg designated as 

 Synapturinae No. 1 by Mito (1963). Yolk can remain unseg- 

 mented, however, as for example in Achirus lineatus and Tri- 

 nectes maculatus. Although the chorion of soleid eggs is usually 

 smooth and unsculptured, Mito (1963) found eggs of Aesopia 

 cormita to have a pattern of large hexagonal meshes. 0.18-0.24 

 mm wide, covering the chorion, and Dekhnik (1973) shows fine 

 polygonal sculpturing on the chorion of P. lascans. 



Eggs of the few cynoglossid species known (Table 172) are 

 small, have homogeneous yolk without secondary segmentation, 

 a narrow perivitelline space and either an unsculptured chonon 

 or one with small polygonal meshes. Oil globules range in num- 

 ber between 5-50, and can be variously distributed in the yolk. 



Robertson (1975a) descnbed eggs of seven species of Rhom- 

 bosoleinae, belonging to four genera (Table 1 72). Egg diameters 

 range from 0.58 to 1.5 mm. Oil globules in described eggs range 



in number from 2-28. Yolk is homogeneous, the perivitelline 

 space IS narrow, and the chonon is smooth. 



Efremenko et al. ( 1 98 1 ) described the ovarian and planktonic 

 eggs of Mancopsetia macidala antarctica and showed that they 

 are large (2.45-2.75 mm) and have multiple oil globules (>20). 

 This finding provides evidence that Mancopsetta does not be- 

 long in the Bothidae. 



Larvae 



In addition to such features as meristics, fin arrangement, and 

 osteology of the fin supports and axial skeleton (which develop 

 gradually during ontogeny and are essential for identification of 

 flatfish larvae) the larval stage itself provides many characters 

 useful in identification and systematic analysis. Larval charac- 

 ters are summarized in Table 173 and below. 



Psettodidae (Fig. 342). — Aboussouan's (1972c) description of 

 prcflexion larvae of Psettodes bennetti was based on five spec- 

 imens. 4.4-5.7 mm in length. Leis and Rennis (1983) describe 

 a series of five larval specimens of Psettodes erumei. 3.0-8.7 

 mm in length. The smallest specimen has a large yolk sac. the 

 6.0-mm larva is in mid-flexion and the largest specimen is 

 undergoing eye migration. Larvae have: a deep, relatively thick 

 body; large head with massive jaws that extend well beyond the 

 rear margin of the eye and bear large, early-forming cursed teeth; 

 large eye; small preopercular spines; and 1 early-forming elon- 

 gate dorsal rays. Dorsal and anal fin rays are all present at 6.0 

 mm but rays do not appear in paired fins until about 8.0 mm. 

 Prcflexion larvae have a series of large melanophores along the 

 dorsal midline, large melanophores alternating with smaller ones 



