Bostrom et al : Hybridization between two serranids, Cephalopholis fulva and Paianthias furcifer 



659 



broad overlap in the geographical ranges of the two spe- 

 cies. Bermuda exists at the northern range of C fulva and 

 P. furcifer, and the two species have restricted spawning 

 times. Cephalopholis fulva and P. furcifer both spawn in 

 Bermuda from May to early August (Smith, 1958, as cited 

 in Thompson and Munro, 1978), and spawning individuals 

 of the two species have been sampled in the same location 

 (Burnett-Herkes, 1975; B. Luckhurst, personal observ.). 

 Similarly, two hybrids have been reported from Jamaica 

 where the parent species also have overlapping spawning 

 times (Thompson and Munro, 1978). 



Hybridization between C. fulva and P. furcifer could 

 be the result of directed interspecific interactions, or the 

 chance meeting of gametes spawned at the same time 

 in the same general location. However, because all 13 F, 

 hybrids were the result of C. fulva eggs fertilized with P. 

 furcifer sperm, it appears that there is a gender bias in 

 hybridization. Possible hybridization scenarios include 

 differences in sex ratio between C. fulva and P. furcifer, 

 a biochemical block on fertilization off! furcifer eggs by 

 C. fulva sperm, or "sneaker" P. furcifer males in C. fulva 

 spawning groups. 



Based on the number of individuals collected in Ber- 

 muda over the last two years, hybridization between C. 

 fulva and P. furcifer seems to be relatively rare. Although 

 the reproductive status of the hybrids is unknown, the oc- 

 currence of two fertile female F, hybrids (one of which was 

 ripe), a spent male F, hybrid, and the presence of post-Fj 

 hybrids, it can be concluded that some F, hybrids are ca- 

 pable of producing viable offspring. However, reproduction 

 of F, hybrids does not appear to be very extensive. Within 

 the limits of the samples analyzed there was no evidence 

 of introgression of alleles between parent species. 



Intergeneric hybridization 



Intergeneric hybridization in animals seems to be rela- 

 tively rare. It is believed that the ability to hybridize is an 

 indication of evolutionary relatedness and that divergent 

 taxa should have lost the ability to interbreed through the 

 evolution of reproductive isolating barriers (Sibley, 1957). 

 However, there are several examples of intergeneric hybrid- 

 ization in fishes, most notably in the cyprinids (Hubbs, 1955; 

 Smith, 1973; Aspinwall et al, 1993; Stauffer et al., 1997). 



Intergeneric hybridization between two such ecologi- 

 cally different species as C. fulva and P. furcifer has also 

 been noted in the lutjanids. Poey (1860) described an in- 

 tergeneric hybrid between Lutjanus synagris and Ocyurus 

 chrysurus. Both Loftus (1992) and Domeier and Clarke 

 (1992) presented reviews of this case of hybridization and 

 Loftus (1992) theorized that the species were capable of 

 interbreeding on the basis of overlap of spawning time 

 and habitat. Both Loftus (1992) and Domeier and Clarke 

 (1992) surmised that O. chrysurug should not constitute 

 its own genus but be included within the genus Lutjanus, 

 owing to its ability to hybridize with a member of that 

 genus. Further support for this revision was provided by 

 Chow and Walsh ( 1992), who reported a high genetic simi- 

 larity between O. chrysurus and several Lutjanus species 

 of the western North Atlantic. They suggested that the 

 species appeared to be misplaced due to its imique mor- 

 phological features. 



A parallel situation exists with the epinepheline serrands 

 because the genetic distance data suggest that P. furcifer 

 does not belong in a separate genus from Cephalopholis. 

 Recently, Craig et al. (2001) used mitochondrial DNA se- 

 quencing to demonstrate a close phylogenetic relationship 



