There is only one genus, Bicaudavirus, and one species, Acidianus two-tailed virus, in this family.

[1][2][3] However, Sulfolobus tengchongensis spindle-shaped viruses 1 and 2 (STSV1 and STSV2) are regarded to belong to this family also.

[5] Virions of both viruses have helical symmetry, with continuous 7-start helices, composed of the single major capsid protein, forming both the tails and the spindle-shaped body.

The major capsid protein structure and virion organization of bicaudaviruses are similar to those of archaeal viruses from the families Fuselloviridae, Thaspiviridae, Halspiviridae and Clavaviridae.

Diverse species of hyperthermophilic archaea from the order Sulfolobales serve as the natural hosts.