FISHERY BULLETIN: VOL. 80, NO. 2 



Table 3.— Body proportions of larvae and juveniles of Ascelichthys rhodorus. Values given for each 

 body proportion are expressed as percent of standard length (SL) or head length (HL): mean, stan- 

 dard deviation, and range. 



'Sample size 

 2 Sample size 



20 



17. 



Values for snout length to anus length continue 

 to increase in postflexion larvae to 45.4% SL and 

 to almost half the body length (49.6% SL) in trans- 

 forming larvae. 



Body depth at the pectoral fin base increases 

 only slightly with development. Preflexion lar- 

 vae have a body depth of 18.5% SL and values in- 

 crease to 25.2% SL in transforming larvae. Adult 

 body depths are usually about 28% SL (Hart 

 1973). 



Meristic Structures (Table 4) 



The following discussion of the development of 

 meristic structures describes only general 

 trends, as specimens show much variation in the 

 sequence of bone ossification and our collection 

 does not include all size ranges. Variation occurs 

 frequently in the size of larvae with respect to the 

 development of meristic structures. In general, 

 the development of meristic characters appears 

 dependent on size rather than age. Different 

 growth rates as seen in standard length differ- 

 ences among individuals and between tanks are 

 also reflected in the development of meristic 

 structures (Tables 1, 4). 



Oral Region 



Branchiostegals are the first meristic struc- 

 tures to develop as ossification occurs as early as 

 6.8 mm SL. The full complementof six branchios- 

 tegals (seven in a few specimens) is not consis- 

 tently ossified until the larvae are 9.0 mm SL. 



Gill arches are stained blue by 9.0 mm SL and 

 most begin to ossify between 8.8 and 9.5 mm SL. 

 Ossification of gill rakers is complete by 13.3 mm 

 SL. 



Axial Skeleton 



Abdominal and caudal centra begin to form 

 350 



between 8.8 and 9.0 mm SL, and development 

 proceeds from anterior to posterior with the first 

 signs of ossification occurring in larvae between 

 8.8 and 9.5 mm SL. Abdominal centra are com- 

 pletely ossified in 10.2 mm SL larvae. Caudal 

 centra begin to ossify in 10.0 mm larvae and ossi- 

 fication of the completed vertebral column ap- 

 pears in 12.8 mm SL larvae. 



Neural and haemal spines begin to ossify in 

 larvae between 8.8 and 10.2 mm SL. All neural 

 spines in the abdominal area are ossified by 10.2 

 mm SL, and the remaining neural spines in the 

 caudal area are complete by 12.8-13.3 mm SL. 

 Haemal spines took up red stain in our 10.2 mm 

 SL larvae but are not completely ossified until 

 12.8-13.3 mm SL. Ossification of both neural and 

 haemal spines proceeds anterior to posterior 

 with the last neural and haemal spines asso- 

 ciated with the caudal complex the last to ossify. 



Fin Development 



In general, all fins except caudal fin rays begin 

 to ossify at 10.2 mm SL. Dorsal spines and pec- 

 toral fin rays are completely ossified by 12.8 mm 

 SL, and dorsal and anal fin rays are fully ossified 

 in 13.3 mm SL specimens. 



The caudal complex begins to ossify with the 

 hypural bones in larvae between 12.8 and 13.3 

 mm SL. The following description is based on 

 our available specimens although our largest 

 juvenile (17.6 mm SL)does not have the full com- 

 plement of ossified caudal fin rays. 



The caudal fin is associated with a complex of 

 4-5 centra (1 ural and 3-4 preural centra), 3-4 

 neural and 3-4 haemal spines, 3 epurals, 1 super- 

 ior hypural (H Y 4-5), 1 inferior hypural (H Y 1-3), 

 and 1 pair of uroneurals (Fig. 2). Caudal fin rays 

 total 31-37 of which 10-13 are superior secondary 

 fin rays and 8-11 are inferior secondary fin rays. 

 Principal caudal fin rays supported by the hy- 

 pural bones number 13 (6 are supported by the 



