Sexual dimorphism is exhibited by B. insignis. Males have the anus situated immediately in front of a genital papilla, which is located immediately posterior to the pelvic-fin base. The genital opening is situated at the tip of the papilla, covered by a fleshy flap. In females, the anus is situated more posteriorly and the genital opening is located at the tip of a short genital appendage. The pelvic fins of females are also more closely set.
