480 



Fishery Bulletin 104(3) 



12 2 mm 



B 



NPU2 EP1 gp2 

 NPU3 \ I J ^EP3 



NC 



15.0 mm 



EP3 



PH-'HY1-2 



VCR ,,„ 

 HPU2 17.0 mm 



D 



EP1»NPU2. ^f^ 

 NPU3*4 



HPU3 / VCR 



HPU2 19 2 mm 



VCR 

 HPU2 21.2 mm 



PH*HY1-2 

 HPU3 "hpu2 42.3 mm 



Figure 2 



Caudal skeleton development of penpoint gunnel iApodichthys fla- 

 vidus). (A) Early-flexion larva, Clam Bay, 27 February 1995 (UW 

 104943): (B) mid-flexion larva (note irregularly shaped EP2), Clam 

 Bay, 10 May 1989 (UW 104937); (C) late-flexion larva. Clam Bay, 19 

 April 1988 (UW 104939); (D) late-flexion larva. Clam Bay, 15 May 

 1989 (UW 104940); (E) postflexion larva, Friday Harbor, 8 April 1993 

 (UW 104943); iF) juvenile. Iceberg Point, 18 July 1963 (UW 018016). 

 Caudal-fin element abbreviations; EP=epural; HPU = haemal spine, 

 preural; HY=hypural; NC = notochord; NPU = neural spine, preural; 

 PH = parhypural; PU = preural centra; U = urostyle; UN = uraneural; 

 VCR=ventral caudal radial. Illustrations by Lisa De Forest. 



surface of the gut than in A. flavidus, and in early- and 

 mid-flexion larvae, these melanophores are restricted 

 to the posterior V4 to V2 of the gut. Another distinguish- 

 ing characteristic is that U. sanctaerosae does not fully 

 develop pectoral-fin rays and the pectoral fin does not 

 persist after the juvenile stage. A pectoral finfold is 

 present during the larval stage of this species; however, 

 only the uppermost pectoral-fin rays (6 or 7 vs. 14 or 

 15 for A. flavidus) partially develop but do not persist, 

 and the pectoral finfold decreases in size during the 

 latter part of development. Larvae of Xererpes fucorum 



can be distinguished from A. flavidus by the presence 

 of a preflexion stage and by having fewer total (84-93 

 vs. 96-101) and postanal (35-40 vs. 47-52) myomeres. 

 In addition, during the later stages of development, X. 

 fucorum has fewer pectoral-fin rays than A. flavidus 

 (12 vs. 14-15). 



Yatsu's (1985) revision of the family Pholidae placed 

 U. sanctaerosae and X. fucorum in the genus Apodich- 

 thys, but this classification was not followed by Mata- 

 rese et al. (1989), Watson (1996), or in the present 

 study. Larvae of both these species are quite similar 



