Upper jaw, | | | | | length | 078 | 077 | 081 | 079 | 077 | (076-081) | | (076-082) | | (076-081) | | | | | Body depth | 239 | 253 | 278 | 274 | 282 | (233-248) | | (261-288) | | (275-294) | | | | | Lateral-line | | | | | scales | 36-37 | 36 | 36-38 | 36.5 | | | | | (34-39) | | | | | | Scales above | | | | | lateral-line | 13 | 14 | 15 | 15 | | | | | (13-16) | | | | | | Anal fin-rays | 9 | 9 | 8 | 8 | | | | | (7-8) | | | | | | Pectoral | | | | | fin-rays | 14 | 14-14 | 15 | 14.2 | | (14-15) | | (14-16) | (12-17) | | | | | | Caudal spot | Absent | Present | Present | Present | Present | | | | | Vertebrae | 37-38 | 38 | 37 | | -----------------+-------------+---------+-------------+---------+------------- [A] Orbital diameter. The air bladder of KU 4253 is nearly as large as in _Gila_, and much larger than the degenerate air bladder of _R. cataractae_. Although the hybrid appears to be male, the gonads (especially the right one) are poorly developed. The hybrid is intermediate in curvature of the lateral line, which is nearly straight in _Rhinichthys_ and strongly decurved in _Gila_. Specimen No. 4253 is mostly pallid, resembling _Gila_ much more than _Rhinichthys_ in pigmentation. A mid-dorsal dark streak is conspicuous in the hybrid, especially anteriorly, but is less intense than in _Gila_. _Rhinichthys_ lacks a well-developed dorsal stripe. The preorbital and suborbital areas are more heavily pigmented in the hybrid than in _Gila_, but not nearly so dark as in _Rhinichthys_. The hybrid has a faint dark basicaudal spot that is variably developed in _Rhinichthys_ but absent in _Gila_.