It was endemic to Western Europe and had a temporal range exclusive to the middle Eocene, although its earliest appearance depends on whether C. argentonicum is truly a species of Catodontherium.

It also had cranial and dental morphologies typical of the Dacrytheriinae but had specific differences from Dacrytherium such as the position of the infraorbital foramen and forms of the premolars and molars.

According to him, the localities of Robiac in France and Mormont in Switzerland have abundant fossil remains of anthracotheres with molars lower in shape than those of the Oligocene-aged Brachyodus.

In 1910, Stehlin validated Catodontherium because its dentition differed from typical Oligocene anthracotheres by its extreme brachydonty (low crowns) and elongated premolars.

The exact evolutionary origins and dispersals of the anoplotheriids are uncertain, but they exclusively resided within the continent when it was an archipelago that was isolated by seaway barriers from other regions such as Balkanatolia and the rest of eastern Eurasia.

[8][13] Dacrytherium itself made its first undisputed appearance by MP13 as an artiodactyl leaning towards bunoselenodont (bunodont (rounded cusps) plus selenodont (crescent-shaped ridge form)) dentition.

After a significant gap of anoplotheriines in MP17a-MP17b, the derived anoplotheriids Anoplotherium and Diplobune made their first appearances in Western Europe by MP18, although their exact origins are unknown.

[15] In 2022 it was suggested that Dacrytheriinae is a paraphyletic subfamily based on dental morphology from which the Anoplotheriinae, Mixtotheriidae, and Cainotherioidea stemmed, but further research is required to confirm if this is true.

[15] The phylogenetic relations of the Anoplotheriidae as well as the Xiphodontidae, Mixtotheriidae, and Cainotheriidae have also been elusive due to the selenodont morphologies of the molars, which were convergent with tylopods or ruminants.

[16] Some researchers considered the selenodont families Anoplotheriidae, Xiphodontidae, and Cainotheriidae to be within Tylopoda due to postcranial features that were similar to the tylopods from North America in the Palaeogene.

[12][18] In an article published in 2019, Romain Weppe et al. conducted a phylogenetic analysis on the Cainotherioidea within the Artiodactyla based on mandibular and dental characteristics, specifically in terms of relationships with artiodactyls of the Palaeogene.

They determined that the Cainotheriidae, Robiacinidae, Anoplotheriidae (represented below by Anoplotherium and Dacrytherium), and Mixtotheriidae formed a clade that was the sister group to the Ruminantia while Tylopoda, along with the Amphimerycidae and Xiphodontidae split earlier in the tree.

[18] The phylogenetic tree published in the article and another work about the cainotherioids is outlined below:[11] Eurodexis russelli Dichobune leporina Amphimeryx murinus Xiphodon castrense Paratoceras coatesi Eotylopus reedi Parvitragulus priscus Lophiomeryx chalaniati Archaeomeryx optatus Mixtotherium cuspidatum Anoplotherium latipes Dacrytherium ovinum Robiacina lavergnesis Robiacina minuta Robiacina quercyi Palembertina deplasi Paroxacron bergeri Paroxacron valdense Oxacron courtoisii Cainotherium laticurvatum Caenomeryx filholi Caenomeryx procommunis Plesiomeryx cadurcensis Plesiomeryx huerzeleri In 2022, Weppe created a phylogenetic analysis in his academic thesis regarding Palaeogene artiodactyl lineages, focusing most specifically on the endemic European families.

The result, Weppe mentioned, matches up with previous phylogenetic analyses on the Cainotherioidea with other endemic European Palaeogene artiodactyls that support the families as a clade.

[16] He also proposed that Leptotheridium, previously relocated from the "Dacrytheriidae" to the Xiphodontidae, composes part of a paraphyletic anoplotheriid clade with the dacrytheriines Catodontherium and Dacrytherium.

The subfamily Anoplotheriinae differs from the Dacrytheriinae by the molariform premolars with crescent-shaped paraconules and the lower molars that lack a third cusp between the metaconid and entoconid.

[17] Alternatively in 1947, Jean Viret and J. Prudant described proximal ends of the radii bones that had typical anoplotheriid morphologies that correspond to unusual forelimb movement compared to other artiodactyls.

They designated one proximal radius end to C. robiacense on the basis that it was transversely enlarged and was primitive in appearance compared to that of Dacrytherium because it was not as differentiated anatomically.

Modern mammalian orders including the Perissodactyla, Artiodactyla, and Primates (or the suborder Euprimates) appeared already by the early Eocene, diversifying rapidly and developing dentitions specialized for folivory.

[29][14][30] The stratigraphic ranges of Catodontherium also overlapped with metatherians (Herpetotheriidae), cimolestans (Pantolestidae, Paroxyclaenidae), rodents (Ischyromyidae, Theridomyoidea, Gliridae), eulipotyphlans, bats, apatotherians, carnivoraformes (Miacidae), and hyaenodonts (Hyainailourinae, Proviverrinae).