TABLE 1.

Current families within the NCLDV superclade (proposed order Megavirales [85])^a

Family	Yr discovered	Host(s)	Replication site	Assembly site	Genome (kb)
Poxviridae	1798?	Vertebrates, insects	Cytoplasm	Cytoplasm	Linear (130–380)c
Asfarviridae	1921	Pigs, warthogs, insects	Cytoplasm	Cytoplasm	Linear (170–190)c
Iridoviridae	1966	Fish, frogs, snakes, insects	Nucleus	Cytoplasm	Linear (102–212)d
Ascoviridae	1983	Insects, moths	Nucleus	Cytoplasm	Circular (157–186)
Phycodnaviridae	1981	Algae	Nucleus	Cytoplasm	Linear (100–560)
Mimiviridae	2003	Amoebae, zooplankton	Cytoplasm	Cytoplasm	Linear (∼1,200)
Marseilleviridae	2009	Amoebae	Cytoplasm	Cytoplasm	Circular (368)
Megaviridae	2010	Amoebae	Cytoplasm	Cytoplasm	Linear (1,208–1,259)
Pandoraviridae	2013	Amoebae	Cytoplasm	Cytoplasm	Linear (1,900–2,500)
Pithoviridae	2014	Amoebae	Cytoplasm	Cytoplasm	Linear (610)d
Faustovirus	2015	Vermamoeba vermiformisb	Cytoplasm	Cytoplasm	Circular (455–470)e

^aThose families considered to be giant viruses, discovered starting in 2003, are shown in bold. Classification and tree topology are still developing, with, for example, the recently discovered Dinodinavirus, Faustovirus, Cedratvirus, Kaumoembavirus, and Mollivirus also being considered members of the NCLDV superclade.

^bA protist.

^cHas covalently cross-linked ends and inverted terminal repeats.

^dCircularly permuted and terminally redundant. The upper size limit is 303 kb if redundancy is included.

^eEight out of nine Faustovirus genomes were circular (129, 130).