Zuhiga and Acuiia Development of Parahchthys spp larvae 



617 



Morphometries 



Six morphometric functional relationships are shown 

 in Figiires 6 and 7, and all linear regression models and 

 their r- values are summarized in Table 3 (abbrevia- 

 tions as in Table 1). In general, all morphometric rela- 

 tionships were adequately described by the linear 

 regression model, especially the preflexion P. adsper- 

 sus larvae which always had higher r^ values than 

 those for other stages of the same species and all stages 

 of P. microps (Table 3). The relationships are not so 

 clear in P. microps, because the preflexion SnL/HL, 

 PAL/SL, BD/SL, and HL/SL relationships had higher 

 r- values than those of the other stages, while the 

 relationships UJL/SL, LJL/SL, and ED/SL of other 

 stages had higher values of r^ than those from pre- 

 flexion (Table 3). 



F tests showed that models for all preflexion rela- 

 tionships and the PAL/SL of "other stages" could be 

 considered statistically identical for both species, while 

 all others were significantly different (Table 4). Regres- 

 sion models for all morphometric relationships (except 

 SnL/HL and PAL/SL) between the two groups of 

 developmental stages of P. microps were significant- 

 ly different, while in P. adspersus all but SnL/HL, 

 PAL/SL, and UJL/SL were significantly different 

 (Table 5). 



A summary of larval characters useful to identify lar- 

 vae of both species during the different larval stages, 

 including morphology, pigmentation, and morphomet- 

 ries, is shown in Table 6. 



Discussion 



Characteristics of larval development of P. adspersus 

 and P. microps are, in general, similar to those ob- 

 served in other species of the genus (P. dentatus Smith 

 and Fahay 1970; P. olivaceus Mito 1963, Okiyama 1967; 

 P. califomicus, Ahlstrom and Moser 1975). Important 

 common characteristics are: presence of only one oil 

 globule posteriad in the yolksac larvae; small size at 

 hatching, notochordal flexion, and metamorphosis; 

 presence of sphenotic spines; two groups of preoper- 

 cular spines; elongated anterior dorsal-fin rays; a deep 

 laterally-compressed body; and a large visceral mass. 

 Opercular spines present in the two species described 

 herein are uncommon in the family. 



Length at hatching of Paralichthyid larvae varies 

 between 1.5 and 3.7mmNL with a mean of 2.2mm, 

 while the range described for the genus Paralichthys 

 is 2.0-2.8 mm (Ahlstrom et al. 1984). Thus, hatching 

 sizes (1.5-1. 7mm) of P. adspersus and P. microps lar- 

 vae are smaller than any known congener. Lengths at 

 flexion and metamorphosis of both species fall within 



