Powell and Henley: Larval development of Paralichthys albigutta and P lethostigma 



513 



Identification of field-collected material Material 

 collected from Onslow Bay off North Carolina was 

 examined to determine the reliability of pigment 

 patterns established from laboratory-reared mate- 

 rial (Table 4). We examined the extent of pigment 

 along the isthmus, lateral pigment in the caudal area, 

 vomer and maxillary pigment, and the extent of pig- 

 ment on the lateral surface of the gut of field-col- 

 lected material. On the basis of our observations, cau- 

 tion must be used when relating pigmentation of 

 laboratory-reared material to field-collected material. 

 Generally, field-collected specimens had less intense 

 pigmentation than those reared in the laboratory 

 (Figs. 3-6). Our observations of vomer pigment, max- 

 illary pigment, and lateral pigment on the surface of 

 the gut on laboratory-reared larvae were not consis- 

 tently observed on field-collected larvae (Table 4). 

 Pigment on the lateral surface of the caudal area that 

 aligned with the myosepta and ventral midline pig- 

 ment that appeared to migrate dorsally on the lat- 

 eral surface was observed only on P. albigutta larvae 

 (laboratory-reared and field-collected). The presence 

 of this pattern might aid in the separation of P. 

 albigutta from P. lethostigma. However, the absence 

 of this pattern has little value because field-collected 

 P. albigutta may lack lateral caudal pigment (Table 

 4) and when present may not always be aligned with 

 myosepta. On preflexion and flexion field-collected 

 Paralichthys larvae, we were unable to define two 

 distinct pigment types but were limited in the num- 

 ber of larvae available. Eight early preflexion larvae 

 (approximately 2.6 mm NL) from Onslow Bay were 



examined for cranial spines, and only two spines or 

 less were observed. We considered these to be P. 

 albigutta on the basis of observations of laboratory- 

 reared material. A collection of material that included 

 early flexion larvae with three cranial spines would 

 be useful 1 ) to verify the presence of three cranial 

 spines in field-collected material and 2) to catego- 

 rize larvae into two types (i.e. three cranial spines 

 vs. < two cranial spines) for a detailed examination 

 of pigment patterns. In addition, the use of otolith 

 characteristics produced during the early larval pe- 

 riod may be useful in facilitating separation of P. 

 albigutta andP lethostigma (Laidig and Ralston, 1995). 



Identification of field-collected specimens was 

 based on stage of development of meristic charac- 

 ters (Gutherz, 1967) (Tables 1 and 2). Unless field- 

 collected material is cleared and stained and then 

 measured, the stage of development of meristic char- 

 acters may not be a valid diagnostic character. The 

 bodies of field-collected material generally are bent, 

 and measurements taken before and after clearing 

 and staining, which tend to straighten the bodies, 

 may vary by 1 mm (Table 4). This is especially perti- 

 nent when attempting to identify flexion and early 

 postflexion larvae by size at a developmental stage. 



Two specimens of Paralichthys squamilentus 

 postflexion larvae were tentatively identified from 

 February collections in Onslow Bay. Pigment at the 

 dorsal and ventral midline resembled P. dentatus 

 (Fahay, 1983). One specimen (5.9 mm SL) had 10 

 postanal melanophores along the ventral midline. 

 Lateral pigment in the caudal area was absent. The 



