FISHERY BULLETIN: VOL. 72. NO. 1 

 Table 5 . — Adult female specimens of Pontellina bearing a spermatophore. 



* One additional specimen was observed in this sample with a damaged spermatophore. 



Morphology and distribution also support 

 our conclusion that the four species are phylo- 

 genetically close and, in fact, comprise a mono- 

 phyletic unit — or holophyletic in Ashlock's 

 (1971) terminology — appearing to have been 

 recently derived from a single tropical-sub- 

 tropical epiplanktonic precursor (in prepara- 

 tion). 



Our objective in this section is to examine 

 the degree of similarity among the siblings as a 

 basis for determining phy logenetic relationships. 

 In the absence of a fossil record, inferences 

 drawn from comparative morphology, geograph- 



ical distribution, and essential habitat adap- 

 tation may provide a relative historical per- 

 spective for judging phylogeny within a taxon. 

 Phylogenetic relationships within P(>)iteUi)io 

 were judged both intuitively and objectively 

 on the basis of characters that showed a cohesive 

 pattern of similarity or dissimilarity. We con- 

 cur with the rebuttals of Throckmorton (1965, 

 1968) and Voris (1971) to the views of orthodox 

 numerical taxonomy in defense of the weighting 

 of taxonomic characters: i.e., characters differ 

 in their taxonomic usefulness, and the adaptive 

 significance of these differences is not beyond 

 logic and comprehension. 



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