M. nigricans may refer to:Makaira nigricans, the Atlantic blue marlin, a fish species endemic to the Atlantic Ocean Mantella nigricans, the Guibé's mantella, a frog species endemic to Madagascar Melanogaster nigricans, a hoverfly species in the genus Melanogaster Melinda nigricans, a fly species in the genus Melinda Micropterus salmoides, the largemouth bass, a fish species found in the United States of America Milax nigricans, Philippi, 1836, a land slug species in the genus Milax Molossus nigricans, a bat species in the genus Molossus Myotis nigricans, the black myotis, a bat species from South and Central America Mucuna nigricans, a plant species in the genus Mucuna