71 



straight in P. cumberlandensis. Mahy (1975b) stated that the posterior margin of the su- 

 praethmoid is concave in P. neogaeus. However, my study showed the posterior margin 

 is not concave but bears a lateroposterior process at the posterolateral portion of the bone 

 in P. neogaeus (TS 43[1]). The processes were not observed in other species of Phoxinus 

 (TS 43[0]). 



In the outgroups, the supraethmoid is elongated and relatively narrow; the middle region 

 of the lateral margin is convex, and the posterior margin is deeply concave. 

 Nasal bone (Fig.37A-G). In cyprinids, the nasal bone is a paired dermal element without 

 direct connection with any other bones. It is placed lateral to the supraethmoid, and an- 

 terolateral to the frontal bone and forms part of the dorsal cover of the olfactory capsule. 

 The bone bears part of the supraorbital canal. In Phoxinus, the nasal bone is narrow and 

 elongated. The supraorbital canal runs through the middle of the bone in P. brachyurus, 

 oreas, phoxinus, tennesseensis, erythrogaster, neogaeus, and cumberlandensis (TS 44[0]; 

 Fig.37A-B); whereas, in P. issykkulensis and eos, the nasal bone is relatively broad and 

 short and expands mesially; the nasal portion of the supraorbital canal runs on the lateral 

 part of the nasal bone (TS 44[1]; Fig.37G). In P. brachyurus and cumberlandensis, the 

 nasal portion of the supraorbital canal is broken at its dorsal side (TS 45[1]; Fig.37A); in 

 other species, the nasal portion of the supraorbital canal is complete (not interrupted) (TS 

 45 [0]; Fig.37B). The relative position of the nasal bone to its neighbor bones also varies 

 among the Phoxinus species. In P. neogaeus, cumberlandensis, and issykkulensis, the entire 

 nasal bone is over the lateral ethmoid (TS 46[1]). In P. brachyurus, oreas, erythrogaster, 

 tennesseensis, eos, and phoxinus, the nasal bone's posterior portion is placed over the 

 lateral ethmoid, while its anterior portion is positioned over the mesethmoid (TS 46[0]; 

 Fig.37A). 



Fig. 37: Dorsal view of mes- 

 ethmoid, lateral ethmoid, 

 frontal, and nasal bones (C-G 

 showing nasal bone only) in 

 Phoxinus. A: P. brachyurus 

 (MCZ 3006, 75.9mmSL);B: 

 P. neogaeus (KU 8521, 53.0 

 mm SL); C: P. tennesseensis 

 (UT 44.5274, 50.0 mm SL); 

 D: P. issykkulensis (P- 10696, 

 NPSCA 4 ^.4 mm SL); E: P. cumber- 

 landensis (KU 18934, 52.0 

 mm SL); F: P. phoxinus (KU 

 22856, 58.0 mm TL); G: P. 

 eos (KU 12255, 33.0 mm 

 TL). Scale bars = 1 mm. 



