noun
metatherians
Zoological term for the clade Metatheria, which includes marsupials and their extinct relatives. Used in academic contexts.
後獣類にはカンガルーやコアラなどが含まれる。
Metatherians include kangaroos, koalas, and others.
有袋類 refers specifically to marsupials (order Marsupialia), a subgroup within Metatheria. 後獣類 is a broader clade that includes all metatherians, both living marsupials and extinct stem-metatherians.
From 後 (こう, 'after' or 'posterior') + 獣 (じゅう, 'beast') + 類 (るい, 'group' or 'category'), a calque of the taxonomic name Metatheria (meta- 'after' + theria 'beasts').