Here we provide a detailed description and diagnosis of Apostolepis albicollaris Lema, 2002, a species known from Central Brazil. The species is easily diagnosable from all its congeners by the following combination of characters: a distinctive white nuchal collar (bordered by a narrow black collar), a very broad black lateral streak (from ventral border to 5th dorsal row), an almost entirely black ventral surface or black with lateral blotches, and 5th 6th supralabials in contact with the parietal (temporals 0 0). Apostolepis albicollaris inhabits interfluvial savannas and appears to be the most abundant species of Apostolepis in the region of the type-locality, located within the core area of the Cerrado domain of Central Brazil. Detected patterns of character state distribution supports the inclusion of A albicollaris in a distinct intrageneric assemblage, here named the dimidiata species-group, an inferred clade diagnosed by the following putative synapomorphies: prominent (to strongly pointed) rostral; slightly rounded terminal shield; snout mostly black with small (to indistinct) light spots; upper lip extensively white; and, in most species, absence of nuchal collars. Although superficially closest to A. dimidiata, no putative synapomorphy was found to support a sister-group relationship between these species. Instead, A albicollaris seems to have retained putatively plesiomorphic features suggestive of an ancient divergence relative to other members of the dimidiata species group.