MATARESE and MARLIAVE: LARVAL DEVELOPMENT OF ROSYLIP SCULPIN 



Little pigment is added until the onset of trans- 

 formation, except on the head, nape, and in the 

 dorsal, anal, and caudal finfolds. Pigmentation 

 changes occurring at the beginning of transfor- 

 mation are visible as early as 44 d after hatching 

 (10.0-11.0 mm SL) but are not consistently visible 

 until the 47th day (13.0 mm SL). During trans- 

 formation A. rhodorus larvae show a rapid in- 

 crease in pigmentation of all areas of the head 

 and nape, and on the anterior dorsal body surface 

 over the gut. A few melanophores appear in the 

 dorsal portion of the postanal body becoming 

 patches of pigment in the upper region dorsally 

 and laterally (Fig. IF). Melanophores also ap- 

 pear in the posterior caudal peduncle area. Early 

 juveniles of the transformed, newly settled A. 

 rhodorus have small, densely concentrated me- 

 lanophores on the entire head, and several spots 

 on the overlying skin over the gut cavity in addi- 

 tion to internal melanophores (Fig. IF). The 

 juveniles also have internal pigment along the 

 notochord, and several distinctive groups of me- 

 lanophore patches in the postanal body region 

 along the upper body and in the caudal peduncle 

 area. Dorsal body pigment on the largest speci- 

 mens (17.0 mm SL) occurs in about five patches 

 located under the posterior portion of the first 

 dorsal fin, at the anterior, posterior, and center 

 of the second dorsal fin, and in the posterior cau- 

 dal area. 



Morphology (Tables 2, 3) 



Head length of A. rhodorus as a proportion of 

 standard length increases with development and 

 becomes almost one-third the standard length in 

 early juveniles. Head length increases from 

 21.3% SL in preflexion larvae to 25.4% SL in lar- 

 vae undergoing flexion. Values for head length 

 continue to increase to 29.5% SL in postflexion 

 larvae and 31.1% SL in transforming specimens. 

 The head length of adult rosylip sculpin is 

 slightly larger than our postflexion and trans- 

 forming larvae; adult head lengths are generally 

 about 37% SL (Hart 1973). 



Eye diameter as a proportion of head length 

 decreases with development. Preflexion larvae 

 have diameters over half the size of the head 

 (50.8% HL), decreasing to 36.6% HL in trans- 

 forming larvae. Eye diameter continues to de- 

 crease in adult rosylip sculpin, usually measur- 

 ing about 25% HL (Hart 1973). 



Snout to anus length as a proportion of stan- 

 dard length increases with development. Snout 



Table 2.— Morphometries (in millimeters) of larvae and juve- 

 niles of Ascelichthys rhodorus. Approximate interval of noto- 

 chord flexion is between dashed lines and interval of transfor- 

 mation is between solid lines. 



'Two ages separated by a slash Indicates a mixed age group, different 

 sibling groups (see Methods). 



length to anus length increases from one-third 

 the standard length (33.2% SL) in preflexion lar- 

 vae to 39.0% SL in larvae undergoing flexion. 



349 



