Megalomyrmex nocarina is a Neotropical species of ants in the subfamily Myrmicinae.

Megalomyrmex nocarina occurs in mature wet forest habitats of the Atlantic slope of Costa Rica.

It is known exclusively as isolated workers in Winkler samples of forest floor litter.

[1] Megalomyrmex nocarina is very easy to confuse with M. mondabora and M. mondaboroides, but the lack of a strong foraminal carina is reliably diagnostic.

Also, the basal mandibular teeth are slightly larger and fewer in number.