Upon its description in 1895, it was classified with the aardvark, but more recent molecular evidence instead suggests that it is most closely related to the tenrecs (a group extant on the island).

Knowledge of the skeletal anatomy is limited, as only limb, partial pelvis, and skull bones have been recovered to date.

French naturalist Henri Filhol first described Plesiorycteropus madagascariensis in 1895 on the basis of a partial skull found at the cave of Belo.

Charles Lamberton, who had access to a larger sample for his 1946 review of the genus, noted substantial variation, but did not attempt to differentiate multiple species.

[7] Remains of both Majoria rapeto and Hypogeomys boulei fall at the upper end of the size range of the genus, indicating that they are referable to P. madagascariensis.

[1] Another Plesiorycteropus innominate was mistakenly assigned to Daubentonia robusta, the extinct giant aye-aye,[8] and other material has been misidentified as of a dwarf lemur (Cheirogaleus).

In his 1946 review, Charles Lamberton was unable to provide a definitive allocation, confused by the various similarities he saw with aardvarks, pangolins, armadillos, and anteaters.

He believed it was most likely a primitive, isolated member of "Edentata", a group in which he included aardvarks, pangolins, and Xenarthra (sloths, armadillos, and anteaters).

He rejected some alternatives, such as a close affinity to aardvarks or the possibility that the material assigned to Plesiorycteropus did not in fact represent a single animal.

[10] Bryan Patterson, who revised tubulidentates (the order of which the aardvark is the only living representative) in the 1970s, accepted Plesiorycteropus as a member of the group, dismissing many similarities with pangolins and other animals as convergent.

[13] Reviewing Patterson's and Thewissen's contributions in 1994, Ross MacPhee found little support for the classification of Plesiorycteropus as a tubulidentate in their data.

[14] MacPhee used a cladistic analysis of eutherians to ascertain the relationships of the genus, but found that while different analytic variants supported different affinities—with aardvarks, hyraxes, ungulates (hooved mammals), and even lipotyphlans (shrews, moles, hedgehogs, and allies)—there was no compelling evidence linking it to any other eutherian group.

[17] He considered it possible but unlikely that a few fossil taxa, such as Palaeorycteropus and Leptomanis from the Paleogene of France, would eventually be found to be bibymalagasians.

[18] Various analyses published by Robert Asher and colleagues in 2003, 2005, and 2007, based on morphology combined with DNA sequence data in some analyses, produced different estimates of the relationships of Plesiorycteropus, some placing it within Afrotheria close to aardvarks or Afrosoricida, but others supporting a relationship with the hedgehog Erinaceus.

He found the animal was most closely related to the tenrecs, a family of insectivorous afrotherian mammals endemic to Madagascar.

[21] Tenrecs are believed to have diversified from a common ancestor that lived 29–37 million years (Ma) ago[22][23][24] after dispersing from Africa via a single rafting event.

[25] Buckley's analysis showed that Plesiorycteropus and the two members of subfamily Tenrecinae tested formed a monophyletic group, within a larger clade in which golden moles are the sister group;[26] he suggested that Plesiorycteropus should be placed in the order Tenrecoidea along with tenrecs as well as African otter shrews and golden moles (the latter two diverged from tenrecs about 47–53 Ma ago[22][23][24] and 59–69 Ma ago,[23][24] respectively).

[Note 3] This is consistent with the trend for larger members of the late Pleistocene and Holocene faunas of Madagascar[36][37] and elsewhere[38] to have been at higher risk of extinction.

Plesiorycteropus lacks notches above the foramen magnum (the opening that connects the brain to the spinal cord), which are present in aardvarks.

[51] The nuchal crest, a projection on the occiput, is straight in P. madagascariensis, but in P. germainepetterae it is interrupted in the middle, similar to the situation in armadillos and hyraxes.

[52] In their descriptions of Plesiorycteropus, Lamberton and Patterson posited different interpretations of the location of the mandibular fossa, where the mandible (lower jaw) articulates with the cranium.

MacPhee found problems with either interpretation and suggested that the true mandibular fossa was part of the area Lamberton identified as such, at the side of the braincase.

[59] A scapula (shoulder blade), only tentatively assigned to Plesiorycteropus, has the acromion, a process, present, but the structure is probably not as large as in aardvarks or armadillos.

[79] Its extinction is somewhat anomalous, as other recently extinct Madagascan animals—such as subfossil lemurs, Malagasy hippopotamuses, the giant fossa, and elephant birds—were generally larger and not exclusively insectivorous; also, some species with likely more specialized diets, such as the falanouc (Eupleres goudoti) and aye-aye (Daubentonia madagascariensis), did survive.