40 



I 



T 



Fig. 18: Phylogenetic hypo- 

 theses of relationships of the 

 hemitremians. A. B: two 

 equal most parsimonious 

 trees; C: strict consensus tree 

 of A and B. The synapomor- 

 phies supporting the nodes of 

 tree C are as following. [The 

 asterisk (*) at the right upper 

 corner of the TS number 

 marks the autapomorphy. The 

 number following nodes A-F 

 correspond to the transforma- 

 tion series (TS) number in pa- 

 ge 26-39]: Node A: anterior 

 placement of the anterior anal 

 pterygiophores: Node B: 20. 

 22*; Node C: 8*. 9*; Node D: 

 18: Node E: 3: Node F: 13. 



in A and B of Fig. 1 8. A strict consensus tree was generated from these two trees (Fig. 18C). 

 The only difference between the tw o equal most parsimonious trees (Fig. 18 A, B) is the 

 relationships among Margariscus, Couesius. and Semotilus. In tree A. [Margariscus + 

 Couesius] is the sistergroup of Semotilus. In the tree B, Margariscus is the sistergroup of 

 [Couesius + Semotilus]. The strict consensus tree (Fig.l8C) shows an unresolved rela- 

 tionship of these three genera. The following discussion is based on the strict consensus 

 tree (Fig.l8C). 



Two major clades are included in the Hemitremian clade: genus Hemitremia. and the Pho- 

 xinus clade including all the remaining genera of the Hemitremian clade. 

 The synapomorphies for each node of tree C (Fig.l8:C) are given below in telegraphic 

 form and include all changes on the node. The number of the transformation series is in 

 parentheses follow ed by a brief description of the character. The asterisk (*) marks the 



