FEENEY: EGGS AND LARVAE OF YELLOWCHIN SCULPIN 



Chitonotus pugetensis eggs (Goldberg 1980; Misitano 

 1980). (The eggs of other Icelinus species have not 

 been described and could not be used for compari- 

 son.) 



The appearance of tubercles on the head of the 

 late-stage embryos has been observed in several 

 other cottid species. Budd (1940) described them in 

 Artedius lateralis and Clinocottus analis as a "patch 

 of minute nodules" which are "believed to aid as a 

 rasp in breaking through the shell . . . allowing the 

 larva to escape anterior end foremost". Bolin (1941) 

 referred to them in Orthonopias as a "large number 

 of small granular patches". Morris (1951) described 

 them in Clinocottiis recalvus as "minute convexities 

 of low elevation which grade into the dorso-anterior 

 surface of the head" and are formed due to the "the 

 extreme pressure which it suffers during its late 

 stages of confinement". In the case of /. quadri- 

 seriatus the head does flatten in the late-stage em- 

 bryos and may be under pressure, but whether these 

 structures form in response to that pressure is not 

 known. The tubercles may serve only to reinforce 

 the area of the head which pushes its way through 

 the chorion. 



Distinguishing Larval Characters 



Distinguishing characters include 1-6 rows of ven- 

 tral gut melanophores, 25-63 postanal ventral mela- 

 nophores, and a distinct lower jaw angle melano- 

 phore on either side. An increasing percentage 

 (25-100%) of larvae over 3.5 mm in each size class 

 develop isthmus, chin, and pectoral insertion mela- 

 nophores. 



Icelinus quadriseriatus larvae are characteristic 

 of the ParicelinuslTriglopslIcelus/Chitonotus/Ice- 

 linus group of Richardson (1981) which is distin- 

 guished by four preopercular spines, a pointed snout, 

 moderately slender body, and postanal pigment 

 restricted to ventral midline. 



Paricelinus, Triglops, and Icelus all have a higher 

 number of vertebrae: 40-42, 44-54, and 37-44 respec- 

 tively (Washington et al. 1984), than /. quadriseri- 

 atus. Paricelinus hopliticus in addition has pigment 

 on the snout, nape, and anterior gut in preflexion 

 larvae. 



Chitonotus pugetensis larvae, while similar in ap- 

 pearance to yellowchin larvae, differ in having 

 several anterior gut melanophores, an early devel- 

 opment of head pigment and a slightly higher range 

 of vertebrae (35-36). Larger (6.0-9.4 mm) C. puge- 

 tensis are more slender-bodied (23-25% SL) (Rich- 

 ardson and Washington 1980) than /. quadriseriatus 

 SL (27-30%). In transforming C. pugetensis larvae 



there are usually three pelvic fin rays and a nuchal 

 spine next to the parietal spine while /. quadriseri- 

 atus has only two pelvic rays and no nuchal spine. 

 The fin ray counts of C. pugetensis (Howe and 

 Richardson 1978) are somewhat higher than the 

 yellowchin, especially the anal fin rays (14-17, x = 

 15.7, in C. pugetensis; 10-13, x = 12.1, in/, quadri- 

 seriatus larvae). 



Artedius creaseri and A. meanyi, recently added 

 to this group (Washington 1986), have anterior gut 

 pigment, pigment in the ventral finfold and fewer 

 postanal ventral melanophores (<13). Postflexion A. 

 creaseri and A. meanyi larvae have nuchal spines 

 next to the parietal spines. 



Seven species oi Icelinus, all with undescribed lar- 

 val stages, co-occur with /. quadriseriatus in the 

 Southern California Bight, including one unde- 

 scribed species (R. Rosenblatt fn. 2). Several larvae 

 have recently been collected at a 75 m depth sta- 

 tion (LACM) that are very similar to field-collected 

 /. quadriseriatus larvae including possession of 

 lower jaw angle, chin, isthmus, and pectoral inser- 

 tion melanophores. A cleared and stained specimen 

 has a count of 38 vertebrae that identifies it tenta- 

 tively as /. tenuis. These larvae differ from /. quadri- 

 seriatus in having a higher myomere count (37-40), 

 anterior peritoneal pigment similar to Chitonotus, 

 and an absence of caudal melanophores. 



ACKNOWLEDGMENTS 



I would like to thank the following for their help: 

 Sally Richardson, Robert J. Lavenberg, William 

 Watson, Gerald E. McGowen, Steven Caddell, 

 Richard Woodsum, Nancy Singleton, Debra Oda, 

 Dennis Chandler, Donna Eto, Frank Edmunds, 

 Gary Brewer, Delaine Winkler, Brian White, Sharon 

 Shiba, Jeffrey Seigel, Camm Swift, Rick Pieper, H. 

 J. Walker, R. Rosenblatt, Daniel Cohen, Jim 

 Rounds, Pacific Bio-Marine Laboratories, the 

 University of Southern California Biology Depart- 

 ment, and the Natural History Museum of Los 

 Angeles County. 



For financial support I thank the Southern Cali- 

 fornia Edison Company and the NOAA Office of Sea 

 Grant, Department of Commerce, under grant 

 numbers 04-8-M-01-186, NA79AA-D-00133, and 

 NA80AA-D-00100 given to the University of South- 

 ern California by Sea Grant. 



LITERATURE CITED 



Bolin, R. L. 



1941. Embryonic and early larval stages of the cottid fish 



211 



