WARNER: REPRODUCTIVE BIOLOGY OF PIMELOMETOPON PULCHRUM 



Males in uniform coloration are more frequent 

 in the Guadalupe population. A total of 6 out of 57 

 (10.5%) uniformly colored individuals vi^ere males. 

 Elimination of immature fish from the count 

 raises the figure to 12.3% males. Four of the six were 

 melanistic, one of these with slight male char- 

 acteristics. The other two individuals possessed 

 normal uniform coloration with no darkening. 



In the third color phase the head region, includ- 

 ing the opercle, is dark brown or black. The chin 

 remains white, and the midsection retains the 

 reddish hue of the uniform type. The caudal por- 

 tion, beginning approximately on a line connect- 

 ing the initial soft rays of the dorsal fin with the 

 anterior limit of the anal fin, is also dark brown or 

 black. The median fins and pelvics remain 

 generally dark in color, and the pectorals may 

 acquire a dark band at their tips. 



This coloration is found exclusively in males and 

 some transitionals (see below). It is usually ac- 

 companied by two other male secondary sexual 

 features common in the Bodianinae, the nuchal 

 hump and filamentous extensions of the median 

 fins. The hump appears to increase in relative size 

 as the male gets larger, making the head appear 

 increasingly angular in profile. No individual with 

 this bicolored pattern was found to have func- 

 tional ovaries. During the breeding season, the 

 pattern serves as an excellent indicator of a func- 

 tional male. 



Individuals classified as transitional varied in 

 coloration. Of 11 transforming California 

 sheephead for which coloration records exist, 3 

 were scored uniform in color and 2 as bicolored. 

 The remaining 6 were recorded as intermediate in 

 coloration, usually involving a slight darkening of 

 the head, caudal region, or both. The three uniform 

 individuals were classed as early transitionals 

 (large amounts of stage 2 oocytes still in the 

 gonad); the two bicolored fishes were classed as 

 late transitionals (only a few degenerating 

 oocytes in the gonad cross-sections). 



The distribution of uniform and bicolored types 

 in field populations, determined by visual tran- 

 sects (Table 6) shows that bicolored males are 

 present in remarkably similar proportions in both 

 localities, occurring in a ratio of about 5.5 uniform 

 individuals to every bicolored individual. Con- 

 fidence limits for estimating the proportion of 

 bicolored individuals were calculated from a 

 binomial distribution, n = 216 and 407 for Cat- 

 alina Island and Guadalupe Island, respectively 

 (Dixon and Massey 1969). 



Table 6.-Numbers of coloration types in two populations of 

 Pimelometopon pulchrum, determined by a series of visual tran- 

 sects. 



DISCUSSION 



Anatomical Features of the Gonad 

 and Sexual Transformation 



The ovary of P. pulchrum is essentially identical 

 with that of the labrid Coris julis, which was 

 studied in detail by Reinboth (1962). Reinboth, 

 however, did distinguish between the testes of 

 those C. julis born as males (primary males) and 

 those that become males through sex reversal 

 (secondary males). In the former, the testis ap- 

 pears rather solid and flattened, and sperm are 

 transported by means of a single vas deferens in 

 each lobe. The secondary male has a testis like that 

 described here for P. pulchrum. The two types 

 differ in the structure of the vas deferens 

 posterior to the gonadal lobes, which surrounds the 

 old oviduct in secondary males, but is a simple tube 

 in primary males (Reinboth 1970). 



When primary and secondary males are present 

 in a single species, Reinboth (1970) termed the 

 species diandric. When only secondary males are 

 present, the species is termed monandric. To 

 Reinboth's (1970) list of monandric species 

 {Labrus turdus, L. merula, L. bergytta, 

 Hemipteronotus novacula, and possibly L. 

 bimaculatus) we may add P. pulchrum. Other 

 labrid species have been studied without regard 

 for the primary-secondary male phenomenon (Atz 

 1964; Reinboth 1970), and cannot be categorized 

 with certainty as monandric or diandric. 



The transition from a functional ovary to a tes- 

 tis has been described in detail for labrid fishes in 

 both naturally occurring situations (Reinboth 

 1962; Sordi 1962; Okada 1962; Roede 1972) and 

 under the influence of hormone administration 

 (Reinboth 1962, 1963; Roede 1972). These reports 

 are essentially in agreement with the present ob- 

 servations on P. pulchrum. There is no evidence of 

 synchronous hermaphroditism (Atz 1964:147) in 

 the Labridae, but Robertson (1972) found sperma- 

 togenic crypts in the ovaries of 28 of 29 females of 



275 



