Mourasuchus is a unique species of prehistoric crocodile so far discovered. It is a filter-feeder and has shared its habitat with Gryposuchus and the more fearsome Purussaurus in the Miocene Era -- reptilian counterpart of the Whale shark and Basking shark.
The original description of the species was given in 1964 by Llewellyn Ivor Price in:
Price, L. I. (1964). "Sôbre o crânio de um grande crocodilídeo extinto do alto Rio Juruá, Estado do Acre". An. Acad. Brasileira Ciên. 36 (1): 59–66.
Fossil crocodilians from Colombia and the Cenozoic history of the Crocodilia in South America (Langston, 1965) has the original description of Mourasuchus, so that would be the definitive source and contain the etymology. Unfortunately, copies of that book appear to be rare and the text not available online.
But guessing that "moura" is Latin or greek in origin leads to a promising result. Moura is the feminine of mourus, which comes from the ancient Greek for "black," "dark," or "obscure."