132 



posttemporal overlaps the pterotic; in P. erythrogaster, only a part of the anterior edge of 

 the posttemporal overlaps the pterotic. The posttemporal does not overlap the pterotic in 

 other species of Phoxinus or in the outgroups (TS 1 86[0] ). 



Supracleithrum (Fig.82A-D). The supracleithrum is an elongated, plate-like bone arti- 

 culating with the posttemporal dorsomedially, and the cleithrum ventromedially. Its ven- 

 tral part is slightly expanded. The dorsal portion of the bone is much narrower than its 

 ventral portion in P. eos and phoxinus (TS 1 87[ 1 ]). The dorsal portion is only slightly nar- 

 rower than the ventral portion in other species of Phoxinus and in the outgroups (TS 

 187[0]). 



Cleithrum (Fig.83A-C). The L-shaped cleithrum is the largest element in the pectoral 

 girdle. It articulates with supracleithrum dorsally, postcleithrum anteriorly, scapula, me- 

 socoracoid, and coracoid posteriorly. Two parts can be recognized from the bone, the ho- 

 rizontal and ascending branches (process). The horizontal branch is the ventral part of the 

 bone and roughly rectangular, with a large notch at the posterior margin. The ascending 

 process is the dorsal part of the bone and roughly perpendicular to the horizontal branch. 

 The ascending process is triangular, and its dorsal tip is sharp. 



The notch of the horizontal branch forming the interosseus foramen with the coracoid at 

 the posterior edge is deep in P. issykkulensis (TS 188[1]), but shallow in other species of 

 Phoxinus and in the outgroups (TS 1 88[0] ). The ventral margin of the ascending process 

 is slightly sloped dorsally in P. issykkulensis (TS 1 89[ 1 ] ); it is more sloped in other spe- 

 cies of Phoxinus and in the outgroups (TS 189[0]). 



Postcleithrum (Figs.83A, 84A-D). This is an elongated rod-like bone attaching to the 

 mesial surface of the cleithrum's ascending process dorsally; its ventral end is sharp and 

 free. No significant variation is present among the Phoxinus species. 

 Coracoid (Figs. 83, 85A-F). The coracoid is a plate-like bone with expansion at the la- 

 teral part to form a broad part. It articulates with scapula laterally and with cleithrum po- 

 steriorly. The slender part, with the posterior margin of the cleithrum, forms the large 

 interosseus foramen. In P. cumberlandensis, eos, neogaeus, and erythrogaster, the slender 

 portion tapers medially; therefore, the posterior portion of the slender part is broader than 

 the medial portion of the slender part in these species (TS 1 90[ 1 ]). In P. phoxinus, brachyu- 

 rus, issykkulensis, tennesseensis, and oreas, the entire slender portion is almost equal in 

 width, which is similar to that in the outgroups (TS 190[0]). In P. cumberlandensis, the 

 bone bears a forked structure articulating with the scapula (TS 1 9 1 [ 1 ] ). The forked struc- 

 ture is absent in other species of Phoxinus and in the outgroups (TS 191 [0]). 

 Mesocoracoid (Figs.84E-H). The mesocoracoid is a roughly T-shaped bone and articu- 

 lates with the cleithrum posteriorly. For sake of description the following terms are given 

 to different parts of the bone. The process articulating with the cleithrum is defined as 

 cleithral process and its anterior end as the cleithral end. The end of the mesocoracoid ar- 

 ticulating with coracoid as coracoidal end. The cleithral end is sharp in P. erythrogaster, 

 cumberlandensis (TS 1 92[1 ]); blunt in other species of Phoxinus and in the outgroups (TS 

 192[0]). The cleithral process is straight in P. cumberlandensis (TS 193[1]); it is slightly 

 bent in other species of Phoxinus and in the outgroups (TS 193[0]). Moreover, a notch is 

 present at the medial margin of the cleithral process in P. phoxinus (TS 194[1]); this notch 



