Anoplotheriidae
Extinct Palaeogene artiodactyls endemic to western Europe.
Wikipedia / Wikimedia Commons
Anoplotheriidae is a family of extinct artiodactyls that existed only during the Palaeogene period. These animals were native to western Europe, appearing from the Middle Eocene through the Early Oligocene. The family splits into two subfamilies: Anoplotheriinae and Dacrytheriinae. The type genus for Anoplotheriinae is *Anoplotherium*, with other members including *Diplobune* and *Ephelcomenus*. Dacrytheriinae, meanwhile, contained only *Dacrytherium* and *Catodontherium*. The naming of *Anoplotherium* in 1804 kicked off the group’s taxonomic history, and the family Anoplotheriidae was formally established by British zoologist John Edward Gray in 1821. Additional genera were described between the late 1800s and early 2000s. Dacrytheriines were originally placed in their own family before later being reclassified as a subfamily within Anoplotheriidae. Taxonomists have sometimes used the superfamily "Anoplotherioidea," but its boundaries remain unclear. Anoplotheriids are thought to be closely related to other extinct artiodactyl families that lived in western Europe at the same time, though their broader evolutionary relationships are still unresolved.
In terms of size, these animals ranged from medium to large. Estimated weights go from about 13.2 kg (29 lb) in *Dacrytherium* up to roughly 266 kg (586 lb) in *Anoplotherium*. The various anoplotheriid species differ from one another, but they generally show some degree of selenodonty—crescent-shaped ridges on their teeth—pointing to a leaf-based diet. They also had a full set of 44 teeth with few gaps (diastemata) between them. Dacrytheriines can be told apart from anoplotheriines by a preorbital fossa (a depression in the skull bone in front of the eye) and several small dental differences. Their skulls are low and their muzzles elongated. Based on available postcranial fossils, some anoplotheriids had two toes (*Anoplotherium commune*), while others (like *Diplobune* and *Anoplotherium latipes*) had three toes—a trait not seen in any other artiodactyls. Because their limb shapes and movements have no clear modern parallels, researchers have proposed unusual behaviours for them: bipedalism in *Anoplotherium*, tree-climbing (arboreal locomotion) in *Diplobune*, and digging (fossorial) abilities in *Ephelcomenus*.
Anoplotheriidae was restricted to western Europe, which during the Eocene was a subtropical to
- Time range
- Middle Eocene to Early Oligocene
- Region
- Western Europe
- Subfamilies
- Anoplotheriinae, Dacrytheriinae
- Type genus
- Anoplotherium
- Estimated weight range
- 13.2 kg (Dacrytherium) to 266 kg (Anoplotherium)
- Dental formula
- 44 teeth, limited diastemata
- Toe count
- Two-toed (Anoplotherium commune) to three-toed (other taxa)
Lore & Background
The taxonomic history of Anoplotheriidae began in 1804 when Georges Cuvier erected the genus Anoplotherium based on fossils from the Paris Basin. The family name was established by John Edward Gray in 1821. Over the 19th and 20th centuries, many genera were assigned to the family, with dacrytheriines initially placed in their own family before being reclassified as a subfamily. The superfamily 'Anoplotherioidea' has sometimes been used, but its definition remains uncertain.
Anoplotheriids were medium to large, with selenodont teeth indicating leaf-eating diets. Their skulls were low with elongated muzzles. Postcranial evidence shows some were two-toed and others three-toed—the latter trait unknown among other artiodactyls. Researchers have theorized unusual behaviors such as bipedalism in Anoplotherium, tree-climbing in Diplobune, and digging in Ephelcomenus due to the lack of modern analogues.
Dacrytheriines appeared earlier, from the Middle to Late Eocene, while anoplotheriines lived from the Middle Eocene to Early Oligocene. After the Grande Coupure extinction event, diversity drastically reduced, with only Diplobune minor surviving into the late Early Oligocene.
Reader's Guide
Anoplotheriidae represents a key group for understanding Palaeogene artiodactyl evolution in western Europe. Their fossils, first described by Georges Cuvier in 1804, played a prominent role in 19th-century palaeontology, with Anoplotherium becoming iconic through sculptures in the Crystal Palace Dinosaurs attraction. The family's taxonomic history reflects shifting classifications, including the eventual inclusion of Dacrytheriinae as a subfamily. The unresolved broader-level relationships of anoplotheriids with other extinct artiodactyl families highlight ongoing debates in mammalian phylogeny. Their unusual limb morphologies—including three-toed forms unique among artiodactyls—and the diverse palaeobiological hypotheses (bipedalism, arboreality, fossoriality) underscore their importance for studying functional morphology and ecological niche partitioning in ancient island ecosystems. The Grande Coupure event dramatically reduced their diversity, with only one species persisting into the late Early Oligocene, illustrating the impact of climate change and faunal turnover on endemic lineages.
Did You Know?
- Anoplotheriidae is divided into two subfamilies: Anoplotheriinae and Dacrytheriinae.
- The type genus Anoplotherium was named by Georges Cuvier in 1804.
- Some anoplotheriids were three-toed, a trait unknown among other artiodactyls.
- Only one species, Diplobune minor, survived into the late Early Oligocene after the Grande Coupure.
Frequently Asked Questions
What is Anoplotheriidae?
Anoplotheriidae is an extinct family of even-toed (artiodactyl) mammals known only from the Palaeogene fossil record. The group is divided into two subfamilies, Anoplotheriinae and Dacrytheriinae, and is restricted to western Europe.
When and where did Anoplotheriidae live?
Members of this family appear in the fossil record from the Middle Eocene through the Early Oligocene. Their geographic range was confined to western Europe, where they occupied various ecological niches before going extinct.
What genera belong to Anoplotheriidae?
Anoplotheriinae includes the type genus Anoplotherium along with Diplobune and Ephelcomenus, while Dacrytheriinae is smaller, containing only Dacrytherium and Catodontherium. Anoplotherium, named back in 1804, anchors the family's taxonomic history.
How big were Anoplotheriidae?
The family spans a remarkable size range, from Dacrytherium at roughly 13.2 kg up to Anoplotherium at an estimated 266 kg. All members shared a dental formula of 44 teeth with limited diastemata (gaps between tooth groups).
Why is Anoplotheriidae significant to Cenozoic mammal evolution?
As a Palaeogene artiodactyl family that left no modern descendants, it offers a window into the diversity of even-toed ungulates before the lineages that dominate today's fauna took over. Its European restriction also helps paleontologists map the biogeographic patterns of early even-toed mammals.
More in Extinct Cenozoic Mammals 1-24
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