Xenarthra

Part of speech: noun

Definitions

1. A group of mammals known for their unique joint structure, primarily consisting of anteaters, sloths, and armadillos
2. Characterized by their peculiar anatomical features, including a lack of teeth and a fusion of some vertebrae
3. These animals are primarily found in Central and South America, showcasing diverse adaptations to their environments

Etymology: Xenarthra is a New Latin coinage from the 1700s-era taxonomic tradition, built from Greek roots: "xenos," meaning "foreign" or "strange," and "arthron," meaning "joint." The name refers to the extra articulations found in the spine of these animals, small additional joints between the vertebrae of the lower back that most other mammals lack. Naturalists who studied these animals noticed the peculiarity and gave the group a name that highlights it. The term was introduced in its modern taxonomic sense by the English naturalist Frederick Cuvier's contemporaries and later systematists, who used it to group the anteaters, sloths, and armadillos. Modern classification has refined the boundaries of the group, and the name has been kept because it still describes a real anatomical feature shared by its members.