Western brook lamprey
Distinguished by the very blunt teeth, the lack of a distinct median tooth on the tongue and the lack of posterial teeth. Anterior dorsal fin lower than the posterior, arising well back on body; caudal fin joined to both dorsal and anal fins; anal fin small, represented in males by a low ridge. Females with a pointed 2nd dorsal fin and a conspicuous anal lobe. Back and sides dark gray to brown, ventral side of body whitish ; fins translucent olive-green and the caudal fin with diffuse black pigment.