Bigmouth Buffalo
  • Side view adult.
  • Side view adult.
  • Side view adult.
  • Top view adult.
  • Bottom view adult.
  • Head-on view adult.
  • Close-up flank.
  • Close-up head.
  • Close-up mouth and snout.
  • Close-up tail.
  • Close-up dorsal fin.
  • Close-up anal fin.
  • Close-up pectoral fin.
  • Close-up pelvic fin.
  • Close-up of head: The lines are indicating distances: eye-preopercle corner, eye-upper gill cleft; E-PC < E-UGC.
  • Close-up of pelvic fin: Notice that the pelvic fin is darkly pigmented.
  • Close-up of mouth: Notice the thin lips; the mouth is terminal; there are no barbels.
  • Body shape: Notice the rounded back without a clear hump; the depth is 30-42% of SL, the head is 28-38% of SL; the sides are dark.
  • Close-up of anal fin: Notice that the anal fin is darkly pigmented; there is no spine and 8-10 rays.
  • Close-up of head: The mouth is terminal.
  • Close-up of dorsal fin: Notice that there are 24-32 rays; spines are lacking.
  • Close-up of head: Notice the minute tubercles on head and scales.
  • Close-up of anal fin: Notice the minute tubercles on the anal fin.
  • Close-up of caudal peduncle: Notice the minute tubercles on anal fin, scales, and tail fin.
  • Side view of young-of-year: The young-of-year are relatively less deep bodied and have a larger eye than adults. They also show black spots (arneascus cysts).
  • Side view of yearling: The yearlings are similar to adults.
  • Alternate side view.
  • Alternate side view.
  • Alternate side view.
DescriptionSimilar Species
Family
Suckers (Catostomidae)
Body
Mouth and snout: inferior, no teeth on jaws. No barbels. Body patterning, color, and scales: Solid dolor. Body overall dark olive, dark gray, or dusky black, grading from darkest on the dorsal surface to lightest on the belly. Fins heavily and darkly pigmented. 34-39 cycloid lateral line scales. Body shape and size: Body somewhat laterally compressed and moderately deep; oval in cross section. Typically 400-500 mm (16-20 in) TL; maximum observed Wisconsin about 800 mm (32 in).
Fins
Tail, dorsal and other fins: Forked tail. Single dorsal with no spines and 24-32 rays; first few rays elongated (about 25-50% of dorsal fin base). Pelvic fins abdominal. Adipose fin absent. Anal fin with 8-10 rays.
Distinguishing Characteristics
The bigmouth buffalo can be distinguished by its lack of a serrated spine at the front of the dorsal and anal fins, its number of anal rays (8-10) and dorsal rays (24-32), by its lack of barbels, by the ratio of the distance from the eye to the ventro-posterior angle of the pre-opercle to the distance from the eye to dorso-posterior edge of the gill opening, which is distinctly less than one, by the presence of a fontanelle (hole) in the roof of the skull between the eyes, a paper-thin pharyngeal arch, linear in cross-section, and a helical (spiral) pattern of coiling of the intestine. See also similar species information.
Breeding Adults
Males minute tubercles on head, scales, and fin rays.
Juveniles
Very small specimens are less deep-bodied with a relatively larger eye.
Hybrids
Smallmouth buffalo X Bigmouth buffalo and Bigmouth buffalo X Black buffalo are plausible but unconfirmed from Wisconsin.
Compare Similar Species
Mouth
Buffalo, BigmouthTerminal; lips thin with shallow grooves
Buffalo, BlackSubterminal or inferior; lips thick with deep grooves
Buffalo, SmallmouthInferior; lips thick with deep grooves
Body Profile
Buffalo, BigmouthDeep bodied, but back more rounded and not as steeply arched as for smallmouth buffalo; BD 30-42% of SL; HL 28-38% of SL
Buffalo, BlackSomewhat deep-bodied, but less so and more elongated than other buffalos; back rounded without a distinctive arch or ridge; BD 29-38% of SL; HL 26-34% of SL; smallmouth buffalo are very difficult to distinguish, except at large sizes (>500mm TL)
Buffalo, SmallmouthVery deep-bodied, sharply arched/ridged back; steep profile from head to dorsal fin, giving a "humped" appearance in lateral view; body depth (BD) about 36-42% of standard length (SL); head length (HL) about 24-29% of SL
Similarity Index
Buffalo, BigmouthN/A
Buffalo, BlackModerately similar
Buffalo, SmallmouthVery similar
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