102 



Hyoid Region 



This region is located posterior to the lower jaw and anterior to the ventral side of the 

 hyomandibular. Via the symplectic and the hyomandibula, this region attaches to the neu- 

 rocranium. Bones included in the region are the interhyal, posterior ceratohyal, anterior 

 ceratohyal, hypohyal, basihyal, urohyal, and branchiostegals. Among them, the urohyal is 

 formed as an "unpaired ossification of the tendon of the sternohyoideus muscle" (Arra- 

 tia & Schultze 1990: 247), the branchiostegal rays are dermal elements, and the other are 

 of chondral origin. 



Urohyal (Figs.62A-C, 63A-D). In cyprinids, the urohyal is a single bone and placed me- 

 dially along the ventral portion of the viscerocranium. The urohyal connects to the ven- 

 tral hypohyal via ligaments anteriorly. The posterior part of the urohyal is attached by the 

 large sternohyoid muscles to the pectoral girdle. 



Fig. 63: Urohyal of Phoxinus 

 (a, lateral, b, ventral and c, 

 dorsal views). A: P. cumber- 

 landensis (KU 18934, 52.0 

 mm SL); B: P. eos (KU 

 12255, 43.0 mm SL); C: P. 

 erythrogaster (KU 5773, 51.5 

 mm SL); D: P. phoxinus 

 (CUNC uncat., 76.0 mm TL). 

 Scale bars = 1 mm. 



