[4] Unaware of Price's discovery, Langston described "Nettosuchus" atopus ("Absurd Duck Crocodile") only a year later based on fragmentary cranial, mandibular and postcranial remains from the middle Miocene La Venta Lagerstätte, a part of the Honda Group.

It wasn't long until the genus returned to four species however, with M. pattersoni (named after Anglo-American paleontologist Bryan Patterson) being described by Cidade et al. the following year.

[11] Mourasuchus is well known for its strange anatomy, its skull exceptionally dorsoventrally flattened, broad, and overall platyrostral in shape, differing greatly from any other caiman currently known, most closely resembling the enigmatic crocodyliform Stomatosuchus from the Late Cretaceous Bahariya Formation.

These results were achieved by specifically restricting the dataset to extant species of caimans, while calculations using measurements from all of Crocodilia generally rendered greater sizes but may be overestimates.

Some studies have proposed that Mourasuchus was closely related to the Eocene Orthogenysuchus from North America, and more distantly to the giant caiman Purussaurus which it shared its habitat with.

However, more recent papers indicate that ongoing preparation conducted on Orthogenysuchus significantly influences the scoring of this taxon's characters, leading to some authors removing the animal from analysis until further publications.

†Mourasuchus pattersoni Much like with the unrelated but morphologically similar Stomatosuchidae, the feeding ecology of Mourasuchus is enigmatic and poorly understood, with a variety of hypotheses having been proposed to make sense of its specialized anatomy.

[8] Langston also proposed a throat pouch based on comments Franz Nopsca made regarding Stomatosuchus, however there is no evidence for such a structure in Mourasuchus nor is its presence certain in stomatosuchids.

As the prey Mourasuchus would have fed on in accordance with the straining technique hypothesis would likely be found either in free water or substrate, the animal would have also captured inedible material during feeding.

Due to the absence of evidence for actual filtering, Cidade et al. instead favors the term "gulp feeding" for Mourasuchus hypothetical hunting behavior.

In the Peruvian Pebas Formation M. atopus was found alongside the large bodied Purussaurus neivensis, a medium-sized species of Gryposuchus, G. pachakamue and three distinct taxa of durophagous caimans.

The later species M. arendsi coexisted with an even greater host of contemporary crocodilians in the Urumaco Formation, sharing its habitat with the larger Purussaurus mirandai, several large-bodied gharials, multiple durophagous caimans and the true crocodile Charactosuchus.

[8] The great diversity of crocodylomorphs in these Miocene-age (Tortonian stage, 8 million years ago) wetlands suggests that niche partitioning was efficient, which would have limited interspecific competition.