 However, there are cases where the unusually small size of a sister group does indeed correlate with an unusual number of ancestral traits, as in "Amborella" (see below).Other famous examples of this phenomenon are the oviparous reproduction and nipple-less lactation of monotremes, a basal clade of mammals with just five species, and the archaic anatomy of the tuatara, a basal clade of lepidosaurian with a single species.The flowering plant family Amborellaceae, restricted to New Caledonia in the southwestern Pacific, is a basal clade of extant angiosperms, consisting of the most basal species, genus, family and order within the group (out of a total of about 250,000 angiosperm species).