[5] Megalocnus was first described based on an incomplete mandible first described by "D. M. F. de Castro", collected by him in April, 1860 in Pleistocene deposits of the thermal springs in Arriete-Ciego Montero in what is now Cienfuegos Province, Cuba, though the fossil now apparently is held in the Museo Nacional de Ciencias Naturales.

[7] The American Museum of Natural History and the notable Cuban scientist Dr. Carlos de la Torre y Huerta collected dozens of fossils of many partial skeletons from 1910 to 1918 at Arriete-Ciego Montero, which resulted in the discovery of enough fossils to mount 3 different skeletons for the AMNH, though only 2 are mounted today at the AMNH, and a skeleton for the Cuban Museum of Natural History.

[6] However, one of the skeletons mounted at the AMNH has since been revealed to bear the right femur of the closely related Parocnus browni.

Woods & co. from Quaternary deposits in Trou Gallery, Ile de la Tortue in the Departement du Nord-Oues, Haiti.

[11] Due to the large sample size of fossils and the number of well preserved skeletons of Megalocnus, the anatomy of the genus is well known, although the taxon has yet to receive any recent research.

[2] Megalocnus largely differs from Hapalops in skull and dental structure, especially in the orientation of the enlarged anterior teeth, and has a heavier body with a broader rib cage, more widely flaring ilium, and more elongate ungual phalanges.

[13] The larger size, relatively shorter tibia, broader rib cage, flared ilia, and other characters of Megalocnus may suggest more terrestrial habits than those of Hapalops or Acratocnus.