Abstract. — The egg and larval de- 

 velopment of Paralichthys albigutta 

 (gulf flounder) and P. lethostigma 

 (southern flounder) are described from 

 laboratory-reared and field-collected 

 specimens. Paralichthys albigutta eggs 

 and oil globules had a mean diameter 

 of 0.87 mm (range: 0.84-0.90 mm) and 

 0.18 mm (range: 0.17-0.19 mm), respec- 

 tively. Paralichthys lethostigma eggs 

 and oil globules had a mean diameter 

 of 0.91 mm (range: 0.84—0.96 mm) and 

 0.18 mm (range: 0.16-0.20 mm), respec- 

 tively. Recently hatched P. albigutta 

 larvae ranged from 1.8 to 2.2 mm in 

 notochord length (NL) and P. letho- 

 stigma from 2.0 to 2.2 mm NL. Pigment 

 on embryos and newly hatched larvae 

 was relatively more developed for P. 

 albigutta. Almost-paired and almost- 

 contiguous ventral midline melano- 

 phores occurred on preflexion larvae of 

 both species and remained throughout 

 the larval stages. Pigment on the max- 

 illary, vomer, dorsum of the mid-brain, 

 lateral surface of the caudal area, lat- 

 eral surface of gut, and extent of pig- 

 ment along the ventral midline of the 

 isthmus were used to separate labora- 

 tory-reared P. albigutta from P. letho- 

 stigma. However, this pigment was less 

 useful in separating field-collected ma- 

 terial. The number of cranial spines 

 appeared to be diagnostic in separat- 

 ing laboratory-reared early-preflexion 

 larvae. Paralichthys lethostigma con- 

 sistently had three cranial spines, 

 whereas P. albigutta had less than 

 three spines. The development of mer- 

 istic characters was considered the 

 most useful character in separating P. 

 albigutta from P. lethostigma because at 

 any given size P. albigutta was generally 

 more developed than P. lethostigma. 



Egg and larval development of 

 laboratory-reared gulf flounder, 

 Paralichthys albigutta, and 

 southern flounder, R lethostigma 

 (Pisces, Paralichthyidae) 



Allyn B. Powell 



Beaufort Laboratory, Southeast Fisheries Science Center 



National Marine Fisheries Service, NOAA 



101 Pivers Island Road, Beaufort, North Carolina 28516-9722 



Theresa Henley 



Beaufort Laboratory, Southeast Fisheries Science Center 



National Marine Fisheries Service, NOAA 



101 Pivers Island Road, Beaufort, North Carolina 28516-9722 



Present address: 4824 N. Britton Drive 



Stillwater, Oklahoma 74075 



Manuscript accepted 20 March 1995. 

 Fishery Bulletin 93:504-515 (1995). 



Four species of the genus Para- 

 lichthys occur in southeastern U.S. 

 coastal waters. Paralichthys squa- 

 milentus (broad flounder) is not 

 commonly encountered and is of 

 little commercial or recreational 

 value. Paralichthys dentatus (sum- 

 mer flounder), P. lethostigma (south- 

 ern flounder), and to a lesser extent 

 P. albigutta (gulf flounder) are com- 

 mon and of great commercial and 

 recreational value (N.C. Div. Marine 

 Fisheries 1 ). Paralichthys dentatus 

 range from Maine to Cape Cana- 

 veral, Florida, and P. albigutta and 

 P. lethostigma range from North 

 Carolina to Texas (Gutherz, 1967). 

 Eggs and larvae of P. dentatus have 

 been described (Smith and Fahay, 

 1970) whereas those of P. albigutta 

 and P. lethostigma have not. Com- 

 parative taxonomic studies of late 

 larvae and early juvenile (fully 

 formed vertebrae, dorsal, and anal 

 rays) P. dentatus, P. lethostigma, 

 and P albigutta have been reported. 

 Deubler (1958) showed that late- 

 larval-early-juvenile P. dentatus 

 can be distinguished from the other 



two congenera by differences in pig- 

 mentation of the dorsal and anal 

 fins and in vertebral number. The 

 only characters useful for separa- 

 tion of P. lethostigma and P. albi- 

 gutta were dorsal-ray and anal-ray 

 counts. Woolcott et al. (1968) 

 showed that 100% separation of the 

 three species could be obtained 

 through a combination of anal-ray 

 and vertebral counts. However, 

 these characters must be fully 

 formed in order to be diagnostic. 

 Vertebral counts alone cannot be 

 used to separate P. albigutta and 

 P. lethostigma. 



The objective of this study is to 

 describe the eggs and larvae of labo- 

 ratory-reared P. lethostigma and 

 P. albigutta to provide diagnostic 

 characters for identification of these 

 paralichthyids in field-collected 

 material. 



1 North Carolina Division of Marine Fish- 

 eries. 1992. Assessment of North Carolina 

 commercial finfisheries. Completion Rep. 

 for Job 2-IJ-16. North Carojina Div. Mar. 

 Fisheries, Morehead City, NC 28557. 



504 



