Natura - nature actualia - actual entities Mundus Plinius - physical world naturalia - natural bodies [crown] Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020] ?"viruses" Order Ortervirales Family Retroviridae 1 Subfamily Orthoretrovirinae 1.0 [Subfamily Oncovirinae] 1.6.0 [Subfamily Lentivirinae] see Subfamily Orthoretrovirinae 2 Subfamily Spumaretrovirinae 2.0 [Subfamily Spumavirinae] see Subfamily Spumaretrovirinae