Metatherians

Part of speech: noun

Definitions

1. A group of mammals distinguished by giving birth to relatively undeveloped young that often continue developing in a pouch or on the mother's body; typically includes marsupials and their extinct relatives; recognized by their unique reproductive strategy and skeletal features
2. Mammals characterized by the birth of neonates that require further postnatal development external to the womb, often involving a pouch; this clade includes living marsupials and certain extinct species known for distinct dental and skeletal traits
3. A subclass of mammals known for producing offspring at an early developmental stage, which complete their growth outside the uterus, commonly in a maternal pouch; encompasses all marsupials and related extinct forms with distinct anatomical characteristics

Etymology: "Metatherians" is the plural of "metatherian," and the word is built from two pieces of Greek. The first, "meta-," means "after" or "beyond," and the second, "therion," means "wild beast" or "small animal." The name "Metatheria" was coined as a formal grouping name in the scientific naming of mammals, and the English suffix "-an" turns it into a noun for a member of that group. The "-an" ending is the ordinary English way of forming a noun or adjective meaning "relating to" or "a member of" a taxonomic group, so the plural simply names the members of the group. Scientists chose the Greek elements to suggest a position in the family tree, and the name is a coinage from classical roots rather than a term used by ancient Greeks, who had no concept of this classification.

Synonyms: marsupials, mammals, therians

Antonyms: placentals, monotremes