51 



of infraorbital, supraorbital, otic, preoperculomandibular. and supratemporal canals (Reno 

 1969). The body lateral line can be incomplete (not extending to the base of the caudal 

 fin, e.g., Rhodeus sinensis), or complete (terminated at the base of the caudal fin, e.g., 

 Rutilus rutilus). 



Cephalic lateral line. As discussed in previous section, three characteristics of the ce- 

 phalic lateral line are present in Phoxinus. 



1. The supraorbital canal is interrupted between the frontal and nasal bones (Fig.6D). 



2. The preopercular canal extends up to the middle of the preopercular's ascending arm 

 only (Fig.8C). 



3. The preoperculomandibular canal is divided to the mandibular and the preopercular 

 canals. These two portions do not connect with each other (Fig.9B). 



Body lateral line (Fig.22A-F). All Phoxinus species bear the body lateral line which 

 is continuous with the cephalic lateral line. The body lateral line in all species is inter- 

 rupted in different regions and shows individual variations in the interruption. 

 Length of the body lateral line varies ontogenetically and phylogenetically. The body la- 

 teral line is shorter in young than in adults (Fig.22A-F). However, length of the body la- 

 teral line in adults has little variation in the same species. In Phoxinus phoxinus, oreas, 

 brachyurus, erythro gaste r, and in the outgroups, the body lateral line extends posteriorly 

 to the caudal peduncle, even to the base of the caudal fin (TS 8[0]; Fig.22F); in other spe- 

 cies of Phoxinus, the body lateral line reaches the middle flank between the origins of the 

 pectoral and pelvic fins, or is even shorter (TS 8[1]; Fig.22A-B, D). 



Genital Papilla (Fig.23A-D) 



The genital papilla is present ventrally just anterior to the origin of the anal fin. Most 

 Phoxinus species exhibit sexual dimorphism in the morphology of the genital papillae. 

 Therefore, it is necessary to describe the papillae for the males and females separately. 

 Males (Fig.23B-C): The ventral surface of the genital papilla is smooth or bears a few 

 skin pleats varying intraspecifically. In Phoxinus tennesseensis and phoxinus, the papilla 

 bears a fleshy projection which extends beyond the anal orifice. In P. tennesseensis, the 

 projection is short and blunt at its posterior end. In P. phoxinus, the projection is slender 

 and longer. The projection is absent in other Phoxinus species. This projection is also pre- 

 sent in Rhynchocypris, Lagowskiella, but absent in Eupallasella (Howes 1985). The pro- 

 jection is present in adult individuals only, not in young ones. Based on the ontogenetic 

 data, I hypothesize presence of the elongated projection the apomorphic (TS 9[1]), and 

 absence the plesiomorphic condition (TS 9[0]). 



Females (Fig.23A, D): In all Phoxinus species, the ventral surface of the genital papilla 

 bears skin pleats. The shape and number of the pleats vary individually. In P. phoxinus, 

 a long and slender projection is present at the posterior end of the papilla (TS 10[1]). The 

 projection is absent in the females of other Phoxinus species (TS10[0]). In some genera 

 of the outgroups, e.g., Rhynchocypris and Lagowskiella, the papilla also bears a short pro- 

 jection, but in Eupallasella the projection is absent (Howes 1985). In P. phoxinus, the pro- 

 jection is absent in young specimens, and present in adult specimens. Based on the 

 ontogenetic data, the presence of the long projection of the genital papilla in P. phoxinus 



