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Description
The Mesungulate Dryolestans were another unique component of South America's Cenozoic animal communities. Originating in the later Cretaceous, these were a lineage of mammals that began to specialize towards a herbivorous diet, with teeth superficially similar to those of basal ungulates from Our World. Due to the limitations of their reproductive systems, they were not able to develop hooves, instead possessing blunt claws. By the Eocene, Mesungulates had become rather diverse in terms of size and ecological niche. Overall there were three main lineages: the Xenohyracoids, Tropidostylopidans and the Vacadactylans. Xenohyracoids tended to be small, non-cursorial browsers that somewhat resembled hyraxes, guinea pigs or gundis and may have been semi-aquatic in some cases. Tropidostylopidans were more lightly built and cursorial, feeding on fruit, leaves and soft vegetation. In form they tended to resemble chevrotains and basal ungulates such as Diacodexis or Dichobunodon, being skittish animals that would run at the first sight of danger. Vacadactylans were significantly larger, being bulky and vaguely wombat-like herbivores equipped with powerful jaws and molars for crushing hard foods. Their limbs were stout, bearing curved, robust claws suitable for digging. The animal at the left of the image is Buskerotherium, a 60cm low browsing Tropidostylopidan of uncertain phylogenetic placement. It was a fairly derived member of the group for the Early Oligocene, with elongated limbs and rather high crowned molars, both features that would be further developed by its relatives later in the Oligocene. The animal to its right is Notoglirodon, a massive Vacadactylan belonging to the family Litonodontidae. Over a metre in length and weighing at least 30kg, this was one of the largest mammals ever discovered on the continent. It was an efficient digger and fed on roots, tubers and tough vegetation. The animal at the bottom of the image is Pepedon, a basal Tropidostylopidan that resembles ancestral forms of the lineage. It was a long bodied and weasel-like genus with a generalistic diet, lacking the cursorial adaptations of its more derived relatives.

Description
The Mesungulate Dryolestans were another unique component of South America's Cenozoic animal communities. Originating in the later Cretaceous, these were a lineage of mammals that began to specialize towards a herbivorous diet, with teeth superficially similar to those of basal ungulates from Our World. Due to the limitations of their reproductive systems, they were not able to develop hooves, instead possessing blunt claws. By the Eocene, Mesungulates had become rather diverse in terms of size and ecological niche. Overall there were three main lineages: the Xenohyracoids, Tropidostylopidans and the Vacadactylans. Xenohyracoids tended to be small, non-cursorial browsers that somewhat resembled hyraxes, guinea pigs or gundis and may have been semi-aquatic in some cases. Tropidostylopidans were more lightly built and cursorial, feeding on fruit, leaves and soft vegetation. In form they tended to resemble chevrotains and basal ungulates such as Diacodexis or Dichobunodon, being skittish animals that would run at the first sight of danger. Vacadactylans were significantly larger, being bulky and vaguely wombat-like herbivores equipped with powerful jaws and molars for crushing hard foods. Their limbs were stout, bearing curved, robust claws suitable for digging. The animal at the left of the image is Buskerotherium, a 60cm low browsing Tropidostylopidan of uncertain phylogenetic placement. It was a fairly derived member of the group for the Early Oligocene, with elongated limbs and rather high crowned molars, both features that would be further developed by its relatives later in the Oligocene. The animal to its right is Notoglirodon, a massive Vacadactylan belonging to the family Litonodontidae. Over a metre in length and weighing at least 30kg, this was one of the largest mammals ever discovered on the continent. It was an efficient digger and fed on roots, tubers and tough vegetation. The animal at the bottom of the image is Pepedon, a basal Tropidostylopidan that resembles ancestral forms of the lineage. It was a long bodied and weasel-like genus with a generalistic diet, lacking the cursorial adaptations of its more derived relatives.