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Fishery Bulletin 93(3). 1995 



aligned with the myosepta as was observed for P. 

 albigutta (Figs. 3D, 4, and 5). 



Other structures and size at transformation 



Dorsal and anal fin supports The arrangement of 

 pterygiophores in relation to neural and haemal 

 spines may be valuable for separating P. albigutta 

 and P. lethostigma larvae because they share simi- 

 lar vertebral counts (hence similar haemal and neu- 

 ral spine counts), but different dorsal and anal fin- 

 ray counts. 



The cumulative number of anal-fin-ray ptery- 

 giophores between the first haemal spine (which is 

 associated with the first caudal vertebrae) and 

 haemal spines posterior to the fourth haemal spine 

 appeared to be diagnostic (Table 3). Although there 

 was overlap in counts, there is a fair degree of sepa- 

 ration in the cumulative number of anal-fin ptery- 

 giophores. For example, between haemal spines 1 and 

 13, from 28 to 31 pterygiophores would aid in identi- 

 fying P. albigutta, whereas >28 pterygiophores would 

 aid in identifying P. lethostigma. As expected, there was 

 a lesser cumulative number of pterygiophores for P 

 albigutta compared with P lethostigma (Table 3). 



The cumulative number of dorsal-fin ptery- 

 giophores between the first neural spine (which is 

 associated with the first caudal vertebrae) and fol- 

 lowing spines appeared less valuable (Table 3). There 

 was considerable overlap between species. The cu- 

 mulative number of pterygiophores was most valu- 

 able when a considerable number were developed. 

 For example, between neural spines 1 and 27, from 

 46 to 52 pterygiophores would aid in identifying P. 

 albigutta, whereas >58 pterygiophores would aid in 

 identifying P. lethostigma (Table 3). 



Cranial spines and preopercle spines Weak, fleshy 

 preopercle spines were observed on both species at 

 all stages, and they decreased in number with in- 

 creasing size (Figs. 3-5). On both species the exact 

 arrangement and number of preopercle spines gen- 

 erally were difficult to discern but were more readily 

 observed in cleared and stained material. Generally, 

 there were four to five minute spines on the inner 

 shelf of the preopercle, a larger spine at the angle of 

 the outer shelf, and one dorsal to the latter on the outer 

 shelf. Preopercle spines were not observed for speci- 

 mens of either species > approximately 8.5 mm SL. 



Cranial spines may be diagnostic for separating P. 

 albigutta and P. lethostigma preflexion larvae. We 

 consistently observed three cranial spines on P. 

 lethostigma preflexion larvae (2.9-5.4 mm NL). We 

 never observed more than two (zero to two) on P. 

 albigutta preflexion larvae of similar size. However, in 



most instances spines could be discerned only on cleared 

 and stained material. Cranial spines generally were 

 never observed on postflexion larvae of either species. 

 Paralichthys albigutta began transformation at a 

 smaller size than did P. lethostigma. For P. albigutta, 

 the migrating eye first appeared at the dorsal mid- 

 line at 7.8 mm SL. On all specimens >7.8 mm SL, 

 the eye had migrated at least to the dorsal midline. 

 For P. lethostigma, the migrating eye first appeared 

 at the dorsal midline at 8.7 mm SL. With one excep- 

 tion, the eye had migrated to at least the dorsal mid- 

 line on all larvae >8.7 mm SL. On one field-collected 

 larva of 11.2 mm SL, the eye had barely reached the 

 dorsal midline as described for P. dentatus (Fahay, 

 1983). Pigmentation and meristic characters clearly 

 identified this specimen as P. lethostigma. 



