64 



A 25000 



20000 



£ 15000 



§ 10000 



5000 



B 



14500 



15000' 



10000 



5000' 



ACCTRAN 

 DELTRAN 

















Erignathus 







Pusa caspica 







Histriophoca 







Pagophilus 





Pusa hispida 





Phoca largha 





Pusa sibirica 





Phoca vitulina 



15000 15500 16000 



Length of tree from exhaustive search 



16500 



Canis 

 Procyon 

 En hydra 

 Lutra 

 Manes 

 Ursus 

 Odobenus 

 Zalophus 

 Cystophora 

 Halichoerus 

 Hydrurga 

 Leptonychotes 

 Lobodon 



Mirounga angusrirostris 

 Mirounga leonina 

 Monachus monachus 

 Monachus schauinslandi 

 Monachus tropicalis 

 Ommatophoca 

 "E-Phocini" 



ACCTRAN 



0 i ■ ■ ■ ■ i ■ ■ ■ ■ i ■ 



60000 65000 70000 75000 80000 



Length of randomly generated tree 



85000 



Fig. 12: Frequency distributions of tree lengths generated from the inversely weighted data matrix 

 with some regions topologically constrained. (A) Clade "anti-Phocini" collapsed (see insert) according 

 to either accelerated (ACCTRAN; g, = -0.483) or delayed transformation (DELTRAN; g, = -0.368) 

 criteria. (B) Clade "E-Phocini" collapsed (see insert) according to either ACCTRAN (g x = -0.540) or 

 DELTRAN (g, = -0.541) optimization. Distributions are of either all 135,135 possible trees (A) or 

 of a random sample of 1.000.000 trees (B). 



