Set of four basal bodies found in Giardia species (trophozoite stage). It comprises the left lateral basal body pair and the left middle basal body pair (i.e. the anterior, ventral, caudal and posteriolateral basal bodies located to the right of the left nucleus of the trophozoite when viewed dorsally).
Comment:
Due to the asymmetric nature of the Giardia trophozoite, this term is defined spatially as the trophozoite is viewed from the dorsal side, with the two nuclei dorsal to the ventral disc, and the ventral disc toward the anterior.