39 



Fig. 17: Lateral view of the posttemporal bone (A-C) and supracleithrum (D-F) of hemitremians and 

 outgroup. A: Campostoma anomalum (KU 3946, 61.0 mm SL): B: Couesius plumbeus (KU 18881, 

 56.6 mm SL): C: Hemitremia flamme a (KU 18931. 57.4 mm SL): D: Dionda episcopa (KU 16891. 

 54.1 mm SL): E: Phoxinus cumberlandensis (KU 18934. 52.0 mm SL): F: Hemitremia flammea (KU 

 18931, 57.4 mm SL). Scale bars = 1 mm. 



extends from the dorsal margin of the neural complex to beyond the neural spine of the 

 fifth vertebra (Fig.löC). In other genera of the ingroups and outgroups, the first supra- 

 neural bone is smaller (Fig.löA, B). - TS 27: Supraneural 4 small [0], or large [1]. 



23. Posttemporal bone (Fig. 17 A-C). Generally, the posttemporal bone is elongated and 

 slender. In the outgroups and in most genera of the ingroup. the ventral portion of the 

 posttemporal is slightly expanded (Fig.l7A, B). In Hemitremia, however, the ventral por- 

 tion of the bone is much larger than the dorsal portion of the bone (Fig.l7C). - TS 28: 

 Ventral portion of posttemporal bone slightly expanded [0]. or broadly expanded [1]. 



24. Supracleithrum (Fig.l7D-F). The supracleithrum is expanded at its middle portion. 

 Therefore, the middle portion of the bone is slightly wider than its dorsal and ventral por- 

 tions (Fig.l7D-E). In Hemitremia, the supracleithrum is relatively short, the middle por- 

 tion of the bone is extremely expanded, therefore, the middle portion is much wider than 

 the ventral and dorsal portions of the bone (Fig.l7F). - TS 29: Middle portion of the su- 

 pracleithrum slightly expanded [0]. or largely expanded [1]. 



Phylogenetic Relationships of the Hemitremian clade 



Appendix I shows distribution of polarities of the 29 transformation series analyzed among 

 the genera of the Hemitremian clade. Based on the matrix of Appendix I, PAUP (version 

 3.0) generated 135,135 trees with tree length from 43 steps to 57 steps. Two most parsi- 

 monious trees were generated with tree length = 43 steps. CI = 0.682 (CI excluding un- 

 informative TS = 0.516). HI = 0.318 (HI excluding uninformative TS = 0.484), as shown 



