Remarkable association of a small infraorbital foramen, similar to that in recent Heterocephalus, and of a strong muscular print on the dorsal anterior part of the zygomatic plate and on the premaxillary. Several anatomical structures to be compared with those of Heterocephalus suggest relationships with this genus. Richardus supports the ancestrality of the hystricomorph character in the bathyergids 

The locality of Montredon has provided 8 species of camivores, often little documented, that are discribed and depicted. All the remains are fragmentary and generally badly preserved which lowers very much the possible precision of the taxonomic study; this one has however allowed the creation of a new subspecies. The most richlypdocumented forms are an ursid (Indarctos) and a felid (Machairodus). Issuing often from a westem Europe evolution, the carnivores are well inserted between those of the better known faunas of the "Classical Pontian" and of the lower Vallesian and this situation fits also well with their stratigraphic level, that cannot however be more accurately defined with them alone.
  

The Montredon site has yielded about hundred rhinoceros remains:
- twenty two of them, including 14 carpal and tarsal bones and 6 complete metapodials, belong to
Dicerorhinus schleiermacheri at its second evolutionary stage;
- fifty one remains including a nearby complete but crushed skull, a mandible, 26 isolated cheek-teeth, 10 carpals and tarsals, one metacarpal, are of Aceratherium incisivum, second evolutionary
stage;
- fifteen remains belong to Aceratherium (Alicornops) simorrense (among other an upper molar, 8 carpals and tarsals, one metatarsal);
- six remains are attributed to an undetermined species of what is probably the most recent Prosantorhinus ever found.
The evolution stages of the two first species allow us to date the deposit back to the Upper Vallesian, MN 10 zone; Montredon is one of the youngest sites in which Aceratherium simorrense was found. The four rhino species indicate a swampy forest biotope