First record of monoclasper in the Banded guitarfish, Zapteryx exasperata in the Gulf of California, Mexico

A mature male of Zapteryx exasperata with the absence of a right clasper is reported for the first time from the Gulf of California. Direct observations on the reproductive system did not show abnormalities or evidence of recent scarring of the right pelvic fin. It is suggested that this condition could be generated by two possible causes: congenital malformation or accidental loss in an early stage of maturity (for example, the bite of a predator).