66 



COMPARATIVE TOOLS 



Constraint analysis 

 Outgroup constraints (Figs. 3 and 13, and Tab.3) 



All outgroup constraints, which forced an alternative set of outgroup relationships to those 

 found in the overall solution, produced cladograms that were longer than the overall 

 solution (Fig. 13 and Tab.3). However, in relative terms, these increases were almost 

 negligible, as even the longest solution (from the constraint tree "ursid - diphyly") of 1,388 

 extra steps (21 corrected steps) only amounts to an increase of 0.77% over the most 

 parsimonious length (of the overall solution) of 69,834 steps. Given such slight increases 

 in length, corresponding bootstrap frequencies for the specific clade(s) under examination 

 were surprisingly low (all below 22%). This might indicate that although very few 

 individual characters directly support the various alternative outgroup relationships, the 



Table 3: Summaries of searches of the inversely weighted data matrix with certain topological 

 constraints of outgroup relationships imposed (see Fig. 3). MPT = most parsimonious trees. Bootstrap 

 frequencies for the desired monophyletic group are given whenever possible. When a constraint tree 

 imposes multiple monophyletic groups, the bootstrap frequency indicated is that of the least supported 

 major clade (indicated by an asterisk). 



Constraint tree Absolute Extra steps relative No. Bootstrap analysis 



length to overall solution of frequency (%) 



(absolute / corrected) MPT 



Pinnipedia 



- monophyly 69834 (+0 / +0) 



- (not) monophyly 70067 (+233 / +4) 



- diphyly 70334 (+500 / +8) 



Ursidae 



- ursid - monophyly 70374 (+540 / +8) 



- ursid - diphyly 71222 (+1388 / +21) 



- ursid - odobenid 70374 (+540 / +8) 



Mustelidae 



- mustelid - monophyly 69834 (+0 / +0) 



- mustelid - diphyly 70334 (+500 / +8) 



Mustelinae 



- musteline - monophyly 70225 (+391 / +6) 



- musteline - diphyly 70708 (+874 / +13) 



Lutrinae 



- lutrine - monophyly 69834 (+0 / +0) 



- lutrine - diphyly 70067 (+233 / +4) 



Miscellaneous 



- (not) otarioid 70067 (+233 / +4) 



- (not) otarioidea 70234 (+400 / +6) 



- odobenid 70234 (+400 / +6) 



687.00 

 115.50* 



680.50 

 115.50 



43.67 

 4.00 



729.33 

 219.67 



59.00 



(69) 

 (12)* 



21.00 (2) 

 < 0.08 (« 1) 



(68) 

 (12) 



(4) 

 (< 1) 



(73) 

 (22) 



(6) 



