6S 



The understanding of the evolution of sexual reproduction hinges 

 on how organisms resolve the conflict between immediate genetic fitness 

 and maintenance of genetic flexibility. Parthenogenetic individuals 

 maximize their genetic representation in future generations and main- 

 tain any adaptive gene combinations. Sexual individuals produce gene- 

 tically diverse offspring (and populations) which may be less prone to 

 extinction in uncertain environments. Comparative genetic, morphologi- 

 cal, and ecological studies of related parthenogenetic and sexual popu- 

 lations are critical. 



Multivariate analyses were done on 13 morphological traits of di- 

 ploid and triploid population samples of Cnemidophorus tesselatus and 

 females of the parental species _C. septemvittatus , _C. tigris and _C. 

 sexlineatus . Comparisons were made only from broad areas of sympatry. 

 Characters for diploid tesselatus were summarized in a weighted hybrid 

 index which maximized the separation between the two parental species. 

 Diploid tesselatus were phenotypically closer to septemvittatus when 

 all 13 characters were compared. They were closer to tigris when the 

 9 scale characters were considered alone, and intermediate between the 

 two parental species when the ^ size-correlated characters were consi- 

 dered alone. The first two character groups also differentiate the two 

 parental species well from each other whereas the latter group does 

 not. Triploid tesselatus are phenotypically closer to diploid tessel- 

 atus than to sexlineatus in all cases. However, the estimated proba- 

 bility that any given unknown sample of triploid tesselatus will actu- 

 ally belong to one of the parental groups is less than .001. No di- 

 ploid population has a probability greater than .01 of belonging to 

 either parental species when all 13 characters are considered. All 

 diploid populations have a probability greater than .05 of belonging 

 to either of the parental species when size characters are considered 

 alone; when considering the 9 scale characters alone, 17 of 51 diploid 

 samples have a probability greater than .05 of belonging to _C. tigris . 



Most characters in diploid tesselatus show dominance or overdom- 

 inance in averages and wide ranges of expression among clones and popu- 

 lations, indicating differing epistatic or genotype-environment inter- 

 actions between the various parental genomes responsible for the origin 

 of diploid tesselatus . Two and four unique clones occur in the vicin- 

 ity of Engle (Sierra Co.) and Conchas Lake (San Miguel Co.), New Mexi- 

 co, respectively, indicating multiple hybridizations between septemvi- 

 ttatus and tigris . It is suggested, based on this, current distribu- 

 tion and possible distributional history, major habitat preferences, 

 and similarities in size, that C_. tesselatus and female _C. septemvitt - 

 atus compete with each other and are in ecological, if not evolution- 

 ary, equilibrium. The implication is that tesselatus is competitively 

 superior under certain conditions. It is suggested that this can be 

 tested with experimental field studies comparing reproduction in sym- 

 patry and allopatry. Multiple hybridizations are the most important 

 source of morphological heterogeneity in C_. tesselatus , which repre- 

 sents a complex of clonal microspecies. The effects of this hetero- 

 geneity among clones on their fitness are unknown; it is likely that 

 discontinuities reflect differences in adaptation, allowing local or 

 regional coexistence of clones. 



