Leptomerycidae

Leptomerycidae is an extinct family of ruminants endemic to North America during the middle Eocene to middle Miocene, making it the longest-living group of ruminants on the continent. Members of the group are medium sized mammals similar in shape to the modern mouse deer, a group which it has been suggested to have been related to, but there were a number of differences. These would mostly be present in the skull with these animals heavily reducing their canines, in contrast to the large canines seen in their relatives. Similar to their overall body shape, members of the family are generally compared to mouse deer in ecology with them also being suggested to be small nocturnal browsers.