Phylum Crenarchaeota Phylum Euryarchaeota Halobacteria Methanobacteria Methanococci Methanopyri Archaeoglobi Thermoplasmata Thermococci Phylum Korarchaeota Phylum Nanoarchaeota
古細菌 (Kó͘-sè-khún) (古細菌; archaea) 是 (sī)現此時 (hiān-chhú-sî)生物 (seng-bu̍t)分類 (hun-lūi)3域 (he̍k)系統 (hē-thóng) (three-domain system) 上 (siāng)頂 (téng)層 (chân)的 (ê)1个 (ê)分類,另外 (lēng-goā)2个是細菌 (sè-khún)佮 (kap)真核生物 (chin-he̍k-seng-bu̍t)。古細菌甘 (ham)細菌仝款 (kāng-khoán),是無 (bô)細胞核 (sè-pau-he̍k) (cell nucleus) 的單細胞 (toaⁿ-sè-pau)生物,算 (sǹg)是1種 (chióng)原核生物 (goân-he̍k-seng-bu̍t) (prokaryote),往過 (éng-koè) "5介 (kài)系統" 的分類共 (kā)列 (lia̍t)做 (chò)Monera。頭起先 (Thaû-khí-seng)掠準 (lia̍h-chún)怹 (in)計 (kè)是極限生物 (ke̍k-hān-seng-bu̍t) (extremophile),尾仔 (boé--á)發現 (hoat-hiān)逐 (ta̍k)種環境 (khoân-kéng)攏 (lóng)有 (ū)古細菌佇咧 (tī--leh)。