The minhocao, like many purported cryptids, appears to be a mix of different species combined under one name. Heuvelmans postulates in On the Track of Unknown Animals that the name is applied to large water snakes (anacondas), an undiscovered primitive cetacean, as well as some relic species of amphibious glyptodont.
The identity of the minhocao as a glyptodont stems from observations of the creature being covered in scales with apparent burrowing habits. Lebino José de Santos was one of the first eyewitnesses of the animal and stated that its skin was thicker than pine bark and possessed scales similar to that of an armadillo. It is also described as an enormous worm-like animal. All observations describe the creature as a large serpentine beast covered in scales. It is important to note that these scales are similar to that of an armadillo rather than a snake, suggesting a mammalian identity for the animal. Heuvelmans suggests that the creature is some sort of glyptodont or armadillo but these animals are not serpentine, and are rather much more roundish in shape. In fact, the shape of a glyptodonts is more aptly compared to that of a tank than to the form of a snake. It appears more likely that the minhocao is a recently extinct of species of New World pangolin.
Although there are no extant pangolins in the New World, there is a fossil record describing such creatures. Record of these two families, Epoicotheriidae and Metacheiromyidae, has been found in the Midwestern United States where many fossils are discovered well preserved. These species are believed to be scansorial; adapted for an arboreal environment. However, not all pangolins are arboreous, as the extant giant pangolin (Manis gigantea) and the cape pangolin (M. temmencki) frequent the ground.
M. gigantea is a prolific digger and has been observed to burrow up to 5 metres deep and 40 metres long. The giant pangolin lives in rainforests similar to the minhocao so it is certainly possible that convergent evolution selected for the two species to be physically similar. Also, pangolins are well-adapted swimmers as the three-cusped pangolin (M. tricuspis) is known to fill its stomach up with air before swimming to improve buoyancy. Thus pangolins are both
powerful burrowers and adept swimmers as the minhocao allegedly is. However, the minhocao is noted for having prominent external ears or horns whereas the African species possess no external ear and in the Asiatic species only a small ridge is visible. An internet search of Metacheiromyidae revealed a sketch of a creature with prominent ears, whether this is pure conjecture or based on the fact that some fossilised ear-print was found is unknown. In the sketch the creature does not possess any type of scales, which seems odd as it belongs to the family Pholidota, meaning 'scaled animals.'
It is most likely that the scales were not preserved in the fossil record and thus not included in the sketch. Ultimately, it is certainly possible that the minhocao is indeed a recently extinct species of New World pangolin as the description fits with many details known about extant pangolins. Unfortunately, there is so little information and an abundance of conflicting reports surrounding the minhocao that a precise identification is impossible.
P., Walker, Ernest. Walker's Mammals of the world. Baltimore: Johns Hopkins UP, 1983.
Heuvelmans, Bernard. On the Track of Unknown Animals. New York: Hill and Wang, 1959.
The Paleobiology Database: http://paleobackup.nceas.ucsb.edu