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Genus Phoxinus 

 brachyurus clade 

 P. brachyurus Berg 

 phoxinus species complex 

 phoxinus species pair 

 P. issykkulensis Berg 

 P. phoxinus (Linnaeus) 

 P. neogaeus Cope 

 erythrogaster clade 



oreas species complex 

 P. oreas (Cope) 

 cumberlandensis species pair 



P. cumberlandensis Starnes & Starnes 

 P. tennesseensis Starnes & Jenkins 

 erythrogaster species pair 

 P. eos (Cope) 



P. erythrogaster (Rafinesque) 



Key to the species of Phoxinus 



1. Intestine shorter than standard length, simply coiled; pharyngeal 

 teeth in two rows; most occurring in Eurasia (only P. neogaeus in 



North America) 2. 



Intestine longer than standard length, coils complex; pharyngeal 



teeth in one row; all occurring in North America 5. 



2. Peritoneum dark; mouth opening large, extending to middle of pupil, 



occurring in North America P. neogaeus 



Peritoneum silver, mouth opening small, extending to the anterior 



margin of orbit, occurring in Eurasian 3. 



3. Side with about 10-15 vertical bars; genital papilla well developed 

 with an elongate posterior process in adult of both sexes; dorsal 



margin of epibranchial 4 deeply forked P. phoxinus 



Side with one longitudinal stripe, without vertical bars; genital 

 papilla small, without posterior process; dorsal margin of 

 epibranchial 4 not deeply forked 4. 



4. Air bladder short and broad P. issykkulensis 



Air bladder slender P. brachyurus 



5. Opercle narrow and elongate P. cumberlan- 



densis 



Opercle broad and short 6. 



6. Dentary relatively short and blunt; pharyngeal bone with two large 



fossae, without small fossae P. eos 



Dentary relatively elongate and slender; pharyngeal bone with more 



than two fossae, both large and small fossae present 7. 



