141 



Similar to the dorsal fin-ray, one or two procurrent rays and seven or eight anal fin-rays 

 are present in the species of Phoxinus. Intraspecific variation of the number of rays is pre- 

 sent: see "Species Account" for discussion on the variation for each species. 



Caudal skeleton and fin rays 



The general morphology of the caudal skeleton of Phoxinus (Fig.92A-C) is similar to that 

 of other cyprinids (c.f. Fink & Fink 1981. Buhan 1972, Mayden 1989). Variation of the 

 caudal skeleton in Phoxinus is found in the single epural and hypural 6. The epural is 

 more slender and longer in P. brachyurus and P. erythro gast er (TS 209[1]) than that in 

 other species of the genus and in the outgroups (TS 209 [0]). Hypural 6 is absent in P. 

 cumberlandensis and P. oreas (TS 210[1]); it is present in other species of the genus or 

 in the outgroups (TS 210[0]). 



Two ty pes of caudal rays can be recognized, the principal and procurrent rays. Similar to 

 other cyprinids (c.f. Fink & Fink,1981. Schultze & Arratia 1989). principal caudal fin rays 

 in Phoxinus are 19 (10+9). The dorsal procurrent rays are from four to 12 in number, ven- 

 tral procurrent rays from four to 10. both of which bear intraspecific variations (see "Spe- 

 cies Account"). 



PHYLOGENETTC RELATIONSHIPS OF THE SPECIES OF PHOXINUS 



Phylogenese Relationships 



Appendix II shows distribution of the polarities of the 210 transformation series among 

 the nine species of Phoxinus. Based on the data matrix in Appendix II. RAUP 3.0 (with 

 exhaustive search) generated 2.027.025 trees from 398 steps to 493 steps in tree length. 

 The most parsimonious tree produced by PAUP is shown in Figure 93. with tree 

 length = 398 steps. CI = 0.546 (CI excluding uninformative transformation series = 0.436). 

 HI = 0.454 (HI excluding uninformative transformation series = 0.564). 

 Two major clades are included in the genus Phoxinus. i.e., brachyums-clade, and erythro- 

 gaster-clade. The brachyurus-clade consists of three recognized Eurasian species of the 

 genus and one North i\merican species. P. neogaeus. The erythrogaster-clade includes the 

 other five North American species of the genus, without P. neogaeus. 

 The synapomorphies for each node (Fig.93) are listed below. The apomorphies of each 

 species are also listed under the appropriate node. 



Node A. This node unites the nine species of Phoxinus as a monophyletic group. Eight 

 synapomorphies support the monophyly of Phoxinus: supraorbital canal interrupted bet- 

 ween nasal and frontal bones: preopercular canal ending at the middle of the ascending 

 arm of preopercle: preoperculomandibular canal interrupted into mandibular and preo- 

 percular canals; breast scales deeply embedded in breeding males; breast scale bearing a 

 series of tubercles at its apical margin in breeding males: scale on caudal peduncle bea- 

 ring three or more tubercles at its apical margin in breeding males; orbital septum lower: 

 phary ngeal pad of occipital bone bearing an anterior process. 



