Lowry et al.: Phytogeny of Oreosomatidae 



701 



the other six species at 17 to 22 loci, in addition to 

 the general protein difference. 



Two loci — AK* and GAPDH-2* — were invariant 

 across all seven oreosomatid species, but only 

 GAPDH-2* differed in all three outgroup species; AK* 

 was different only in C. australis. These loci are con- 

 sistent with a monophyletic origin of the oreosomatids. 

 Three loci (GAPDH-1*, mIDHP*, and sMDH-2*) were 

 monomorphic for the same allele in six of the seven 

 oreo species, with O. atlanticum fixed for alternative 

 alleles; these putative synapomorphies indicate that 

 these six species are probably monophyletic. 



It is therefore not surprising to find that O. 

 atlanticum was clearly separated from the other 

 oreosomatid species on the phenogram 

 constructed by the UPGMA method 

 from Nei's ( 1978) unbiased genetic dis- 

 tances (Fig. 2). Branching order and 

 significance of the branching nodes did 

 not differ with the choice of outgroup. 

 The three Neocyttus species and A niger 

 formed a distinct cluster. There was a 

 very close association of the Southern 

 Hemisphere N. rhomboidalis and the 

 Northern Hemisphere N. helgae. 



The phylogenetic tree constructed 

 by the distance-Wagner procedure 

 from Rogers' (1972) distances, rooted 

 by the outgroup C. australis, also 

 showed the divergence of O. atlanti- 

 cum from the other oreosomatids (Fig. 

 3). Although the closeness of N. 

 rhomboidalis and N. helgae was main- 

 tained, and again the two Allocyttus 

 species were not grouped together, P. 

 maculatus was found to be grouped 

 with A. niger and N. sp. A similar tree 



I s 



was produced, by this procedure, with N. tuberosus 

 as the outgroup, whereas the tree produced with B. 

 splendens as the outgroup resembled those from the 

 UPGMA cluster analyses (with P. maculatus diver- 

 gent from the Neocyttus and Allocyttus species); a 

 similar tree was produced when all three outgroups 

 were applied together. 



Cladistic analysis (PAUP) with all three outgroup 

 species together produced 55 most parsimonious 

 trees, all of which showed the divergence of O. 

 atlanticum from other members of the family, but 

 failed to define any structure for the other six spe- 

 cies. Analysis with C. australis as the outgroup pro- 

 duced eleven most parsimonious trees of 52 units in 



rS 



i 



N. rhomboidalis 

 N. helgae 

 A. niger 

 N. sp. 



A. verrucosus 

 P. maculatus 

 O. atlanticum 

 C. australis 



i 



_L_ 



1.2 0.9 0.6 



Genetic distance 



ii J 



0.0 



Unweighte 

 phenogram 

 boxes repre 



Figure 2 



d pair-group method with arithmetic averaging (UPGMA) 

 constructed from Nei's (1978) unbiased genetic distance. Open 

 sent standard errors (Nei, 1987) of the branch nodes. 



