The material documented so far consists mainly of limb bones but includes individual skulls and remains of jaws.

A possibly related Pseudoprepotherium tibia from the Middle Miocene Pebas Formation near Iquitos in the western Amazon Basin, about 23 cm long, shows more than 60 bite marks, the size and arrangement of which suggest that they were probably caused by a juvenile Purussaurus.

[6] In a classic system based on skeletal anatomical features, the Mylodontoidea form a sister group to the Megatherioidea and thus one of the two major lineages of sloths.

Characteristic features can be found in the high-crowned teeth, which, unlike those of the Megatherioidea and Megalocnoidea, have a rather flat ( lobate) possess chewing surface.

A relatively wide recognition usually only finds the late development lines with the Mylodontinae and Lestodontinae, as several studies have shown since 2004,  but they are sometimes also discussed negatively.

In principle, many researchers urge a revision for the entire family since many higher taxonomic units have no formal diagnosis.

Based on their characteristics, phylogenetic analyzes indicate that Pseudoprepotherium is more closely related to some more modern representatives, such as Thinobadistes, a form widely found in Central and North America.

Therefore, investigations on the little skull material see Pseudoprepotherium clearly more basally embedded in the mylodonts and move the form partly closer to Urumacotherium, but also to the Scelidotheriidae.

He mentioned them in a publication of a skeletal description of Planops, a member of the Megatheriidae from the Santa Cruz Formation of Patagonia's Early and Middle Miocene.

In 1961, Hoffstetter classified this femur as part of the Prepotherium genus based on anatomical differences and established a new one with Pseudoprepotherium .

The other two species, which are significantly larger with femur lengths of 56 to 59 cm, were recognized in 2006 by a work team led by Alfredo A. Carlini but were originally included in the genus Mirandabradys .

Carlini and colleagues had defined this using numerous finds from the Urumaco sequence in the Falcón Basin of north-western Venezuela, the chronological range of which includes the Middle and Upper Miocene.

Referring to deviations in the structure of the femur, Rincón and McDonald reclassified the 2020 form as the type species of the new genus Magdalenabradys.

The site contained a small collection of vertebrates, such as remains of fish and crocodilians; such as Purussaurus, which preyed on ground sloths like Pseudoprepotherium,[9] as well as armored Peltephilidae and South American ungulates.

It is composed of the lithostratigraphic units of the Socorro, Urumaco and Codore Formations, with remains of Pseudoprepotherium being limited to the two lower and first-mentioned sequences.

The main components are different layers of sand, clay, and/or silt and limestone in which individual coal seams are embedded, at least in the Urumaco Formation.

In addition, there are also reptiles such as turtles, crocodilians, and isolated snakes, as well as mammals appearing with rodents, South American ungulates, manatees, and minor jointed animals, among others.

The secondary articulated animals show a high diversity, almost reaching that of the contemporary fauna of southern South America in the Pampas region or Mesopotamia.

[11][12][13] Mainly in the late 20th and early 21st century, numerous new forms were described, such as Urumacocnus and Pattersonocnus from the family Megalonychidae, Urumaquia and Proeremotherium as representatives of the large Megatheriidae and Magdalenabradys, Bolivartherium, Eionaletherium and Urumacotherium from the lineage Mylodontidae and their immediate relatives.

As a special circumstance of taphonomy, the frequent tradition of limb elements in sloths is to be evaluated, however, from Pseudoprepotherium also documented remains of the skull.

[14][3][15][4] Finds possibly related to Pseudoprepotherium come from the western Amazon basin and date to the Middle to Upper Miocene.

These go back to a phase when the so-called "Proto-Amazon" existed, a landscape characterized by lakes, swamps and rivers connected to the Caribbean.