palaeococcus palaeococcus in taxonomy, palaeococcus is a genus of the thermococcaceae. palaeococcus scientific classification domain: archaea kingdom: euryarchaeota phylum: euryarchaeota class: thermococci order: thermococcales family: thermococcaceae genus: palaeococcustakai et al. 2000 non cockerell 1894 type species palaeococcus ferrophilustakai et al. 2000 species p. ferrophilus p. helgesonii p. pacificus phylogeny 16s rrna based ltp_12_2021. 53 marker proteins based gtdb 07-rs207. palaeococcus p. pacificus zeng et al. 2013 p. ferrophilus takai et al. 2000 p. helgesonii amend et al. 2006 palaeococcus p. pacificus p. ferrophilus