活化石 (huóhuàshí): living fossil

Often used metaphorically as well — for traditions, languages, or institutions that have survived nearly unchanged from ancient times. The species pairing 活 'living' + 化石 'fossil' is paradoxical on purpose: something that should only exist as a fossil is somehow still alive.

memory

Same construction as English: 'living + fossil.' Useful trio: 银杏 (yínxìng, ginkgo), 大熊猫 (dàxióngmāo, panda), 中华鲟 (Zhōnghuáxún, Chinese sturgeon) — China's three most-cited 活化石.