660 



ONTOGENY AND SYSTEMATICS OF FISHES- AHLSTROM SYMPOSIUM 



four plus terminal notochord pigment (Richardson, 1981b); 

 G/yptocephalus zachirus has pigment bands which alternate with 

 ventral patches, plus the terminal notochord pigment. 



At least four other genera of pleuronectine flatfishes occur in 

 the eastern North Pacific. The preflexion stage larvae of Pleu- 

 ronectes pallasii, Liopsetta glacialis. and Limanda aspera lack 

 melanistic bands (Pertseva-Ostroumova, 1961). Larvae are un- 

 known for the fourth genus, Clidoderma. 



Larvae are known for species representing six additional gen- 

 era in the western North Pacific. According to Pertseva-Os- 

 troumova (1961), preflexion larvae o{ Acanthopsetta nadeshnyi 

 and Kareius bicoloratiis lack bands; those of Cleisthenes her- 

 zensteini (see also Okiyama and Takahashi, 1976), Pseudopleu- 

 ronectes herzensteini and P. yokohamae (see also Dekhnik, 1 959; 

 Yusa, 1960a, b; Yusa et al., 1971) have two tail pigment bands 

 plus terminal notochord pigment. Preflexion larvae of I erasper 

 vahegatus (Fig. 349) are as heavily pigmented as those of Pleii- 

 ronichthys (Takita et al., 1967; Uchida, 1933). The pigment 

 pattern on preflexion larvae of Tanakius kitaharai is very sim- 

 ilar to that on larvae of Glyplocephalus stelleh (Okiyama and 

 Takahashi, 1976). Larvae have not been described for the mono- 

 typic genus Dexistes. 



In species with banded preflexion larvae, the bands usually 

 persist into later larval stages; those with diffuse or linear pig- 

 ment patterns generally do not develop bands in later stages, 

 although pigment may become associated with myosepta (Figs. 

 352, 353). Virtually all late postflexion and metamorphic pleu- 

 ronectines develop a distinct pattern of bars or blotches on the 

 body and median fins, which persists into the juvenile stage 

 (Fig. 354). 



Of the four other pleuronectid subfamilies, larvae have not 

 been described for Paralichthodinae, while some information is 

 available on the Samarinae, Poecilopsettinae, and Rhomboso- 

 leinae. Pertseva-Ostroumova (1965) described two larval spec- 

 imens (6.4, 8.7 mm) of Samaris cnslatus and Struhsaker (pers. 

 comm.) has described large pelagic larvae of Samariscus sp. and 

 Poecilopsetta hawaiiensis (Fig. 355). Larvae of S. cristatus are 

 deep-bodied in the gut region, have a relatively large head and 

 jaws and a pigment pattern consisting of melanophore patches 

 along the dorsum and ventrum. along the outer margins of the 

 pterygiophore zones, and along the dorsal and anal fins; the 

 ventral region of the gut is pigmented. A series of Samariscus 

 triocellatus, 7.3-19.0 mm (provided by Dr. T. A. Clarke, Univ. 

 of Hawaii), is similar to Samaris cristatus in having a slender 

 body and wide pterygiophore zones but the gut coil is elongate, 

 protrudes beyond the ventral profile, and the fourth dorsal ray 



is elongate. The left eye has begun to migrate at 7.3 mm and is 

 at the dorsal midline by 12.0 mm. Larvae of Samariscus cor- 

 allimts are similar but attain a larger size (ca. 26 mm). Both 

 species lack pigment. Late postflexion larvae of Poecilopsetta 

 have a body form similar to samarines (slender body with wide 

 pterygiophore /ones) but have a different gut structure, no elon- 

 gate dorsal ray, and have a striking pigment pattern consisting 

 of dorsal and ventral myoseptal series and large blotches over 

 the pterygiophore zones, dorsal and anal fins, and gut (Fig. 355). 

 A 29-mm late postflexion larva from the North Atlantic has a 

 pigment pattern identical to Hawaiian specimens. 



Reared yolk-sac and early preflexion larvae of rhombosoleine 

 species have been illustrated and briefly described: Ammotretis 

 rostratus (Thomson, 1906); Rhomhosolea plebeia (Anderton, 

 1907); Colistnim glint hen. Pclotretis flavilatus. and Peltorham- 

 phus novaezeclandiae (Thomson and Anderton, 1921). The oil 

 globules remain evenly dispersed throughout the yolk-sac pe- 

 riod. Heavy melanistic pigmentation develops on the head, body, 

 yolk sac, and finfold. Late yolk-sac larvae of C gunthcri deve\op 

 an unusual lobate projection of the dorsal finfold, which extends 

 well anterior to the head. A similar structure appears in yolk- 

 sac larvae of the soleid, Pcgusa lascaris (Holt, 1891). Rapson 

 ( 1 940) described and illustrated with photographs a reared series 

 of Pelot ret is Jlavilat us. Flexion-stage larvae of this species are 

 deep-bodied and similar in appearance to paralichthyids, al- 

 though they lack elongate dorsal fin rays (Fig. 355). Pigmenta- 

 tion consists of dorsal and ventral midline series, series above 

 and below the spinal column, a linear patch below the gut, and 

 embedded melanophores in the otic region. Postflexion larvae 

 become mottled with large blotches on the body and fins. Cross- 

 land (1981) briefly described and illustrated pre- and postflexion 

 stages of a similar larva which he identified as Pe/torhamphus 

 latus and stated that Rapson's ( 1 940) series was a species of 

 Peltorhamphus. Crossland's (1982) illustration of a flexion-stage 

 Pelotrelis flavilatus has heavy pigmentation, a protruding gut 

 mass and looks very much like a soleid. 



Soleidae (Fig. 356).— Two subfamilies, Soleinae and Achirinae, 

 are recognized in the family. In the Soleinae, life history stages 

 are well known for the eastern North Atlantic species, Solea 

 solea. Microchirus varicgaius. Buglossidium luteum and Pcgusa 

 lascaris (references summarized in Ehrenbaum, 1905-1909 and 

 Russell, 1976). A comprehensive volume on the development 

 of 5. solea was produced by Fabre-Domergue and Bietrix (1905). 

 Padoa (1956k) summarized information on eggs and larvae of 

 soles from the Mediterranean, and Aboussouan (1972c) briefly 



Fig. 350. Larvae of Pleuronectidae. (A) Hippoglossus stenolepis. 1 5.0 mm, from Pertseva-Ostroumova. 1 96 1 ; (B) Reinhardlius hippoglossoides. 

 17.0 mm, from Jensen, 1935; (C) Lyopselta exilis. 5.9 mm from Ahlstrom and Moser, 1975; (D) Parophrys vetulus. 4.3 mm, ibid; (E) Ptatichthys 

 slellatus. 2.6 mm, from Orcutt, 1950; (F) Atheresthes stomias. 10.5 mm, original; (G) Eopsetta jordani. 6.2 mm, from Alderdice and Forrester, 

 1971. 



Fig. 351. Larvae of Pleuronectidae. (A) Isnpsetta isolepis. 9.5 mm, original, CalCOFI 7205, Sta. 40.38; (B) Lepidopsena bihneata. 4.6 mm, 

 from Pertseva-Ostroumova, 1965; (C) Pseltichlhys melanoslictus. 6.7 mm, original, CalCOFI 5807 Sta. 40.38; (D) Hippoglossnide.s eta.ssodon. 

 9.2 mm, from Pertseva-Ostroumova, 1961; (E) Microstornus pacificus. 7.0 mm, redrawn from Ahlstrom and Moser, 1975; (F) Embassichlhys 

 balhybius. 18.5 mm, original, CalCOFI 4905, Sta. 29.83; (G) Glyplocephalus zachirus. 22.8 mm, redrawn from Ahlstrom and Moser, 1975. 



Fig. 352. Larvae of Pleuronectidae. (A) Lyopselta exilis. 14.7 mm, original. CalCOFI 7805, Sta. 100.29; (B) Parophrys vetulus. 16.0 mm, 

 redrawn from Ahlstrom and Moser, 1975; (C) Isopsetla isolepis. 14.2 mm, original, CalCOFI 7205, Sta. 40.38, (D) Eopsetta grigorjewi, lO.O mm, 

 from Okiyama and Takahashi, 1976; (E) Pseltichlhys melanoslictus. 9.4 mm, original, CalCOFI. 



