406 



Fishery Bulletin 91(3), 1993 



by 17.2 mm. Breast plates on the 

 ventral surface of the abdomen 

 and pelvic region are complete 

 by 12.6 mm. The number of pec- 

 toral-fin base plates in 0. 

 trispinosa is variable ranging 

 from 3 to 8 among specimens ex- 

 amined. Ossification of pectoral- 

 fin base plates is complete by 

 about 13.8 mm. 



Development of 

 Xeneretmus latifrons 



Morphology Larvae of X. 

 latifrons are deeper bodied than 

 0. trispinosa; mean body depth 

 at the pectoral-fin origin ranges 

 from 13.3% SL in preflexion 

 specimens to 14.6% SL post- 

 flexion (Tables 5 and 6; Fig. 6). 

 Head length increases from 

 20.3% SL in preflexion larvae to 

 26.6%' SL in postflexion larvae, 

 and snout length as a propor- 

 tion of head length increases 

 from 18.8% HL in preflexion lar- 

 vae to 24.4% HL in postflexion 

 larvae (Table 6). Eye diameter 

 decreases from about 37.5% HL 

 in preflexion larvae to 28.4% HL 

 in postflexion larvae, and head 

 width remains approximately 

 54-55% HL throughout develop- 

 ment (Table 6). 



Pectoral-fin length increases 

 from 8.4% SL in preflexion lar- 

 vae to 21.8% SL in postflexion 

 larvae. In preflexion larvae, 

 snout to anus distance is 51.7% 



Table 5 



Morphometric measurements (in millimeters) of 45 Xeneretmus latifrons larvae. Speci- 

 mens between dashed lines ( ) were undergoing notoehord flexion. 



Standard Body 

 length depth 



Snout to 

 anus length 



Head 

 length 



Head 



width 



Snout 

 length 



Eye 

 diameter 



Pectoral 

 fin length 



4.9 



5.1 

 5.1 

 5.3 

 5.5 

 5.6 

 6.0 

 6.0 

 6.8 

 6.8 

 7.0 

 7.2 

 7.8 

 7.9 

 8.3 



8.9 



9.3 



9.8 



9.9 



10.0 



10.0 



10.5 



10.8 



0.72 

 0.66 

 0.70 

 0.66 

 0.76 

 0.68 

 0.78 

 0.72 

 0.82 

 0.80 

 1.10 

 0.88 

 1.16 

 0.96 

 1.30 



1.14 

 1.30 

 1.18 

 1.60 

 1.20 

 1.48 

 1.50 

 1.72 



2.20 

 2.56 

 2.48 

 2.40 

 2.88 

 2.92 

 2.92 

 2.98 

 3.40 

 3.36 

 3.80 

 4.04 

 4.80 

 4.12 

 4.78 



0.84 

 0.96 

 1.06 

 0.90 

 1.26 

 1.00 

 1.14 

 1.15 

 1.32 

 1.20 

 1.66 

 1.80 

 2.08 

 1.54 

 1.54 



0.48 

 0.50 

 0.54 

 0.44 

 0.66 

 0.50 

 0.64 

 0.60 

 0.66 

 0.66 

 0.80 

 1.00 

 1.08 

 0.84 

 1.13 



0.06 

 0.16 

 0.20 

 0.16 

 0.26 

 0.20 

 0.23 

 0.22 

 0.24 

 0.20 

 0.28 

 0.42 

 0.56 

 0.30 

 0.32 



4.78 

 5.67 

 5.33 

 5.50 

 6.08 

 5.67 

 5.75 

 6.17 



1.94 

 2.68 

 2.44 

 2.56 

 2.44 

 2.36 

 2.96 

 2.68 



1.04 

 1.52 

 1.24 

 1.44 

 1.36 

 1.30 

 1.64 

 1.42 



0.44 

 0.50 

 0.56 

 0.64 

 0.60 

 0.54 

 0.62 

 0.62 



0.38 

 0.38 

 0.38 

 0.38 

 0.40 

 0.40 

 0.44 

 0.40 

 0.46 

 0.42 

 0.46 

 0.52 

 0.64 

 0.48 

 0.61 



0.62 

 0.82 

 0.68 

 0.74 

 0.74 

 0.70 

 0.86 

 0.80 



0.34 

 0.34 

 0.38 

 0.32 

 0.44 

 0.40 

 0.50 

 0.40 

 0.42 

 0.50 

 0.52 

 1.08 

 1.14 

 0.62 

 0.81 



0.88 

 1.80 

 1.50 

 1.80 

 1.62 

 1.42 

 2.48 

 2.14 



