It can be easily distinguished from all other trilobites by the combination of the absence of dorsal sutures in the head shield like all Olenellina (which in all other trilobite suborders assist in moulding by splitting open), and a distinctly bulbous frontal lobe (L4) of the raised axial area in the head (or cephalon) called glabella.
Bolbolenellus is the combination of Greek βολβός (bolbos, “plant with round swelling on underground stem”), and Olenellus, the rather distantly related genus to which all of the species were previously assigned.
Although most of the body is rather flat, the frontal lobe (L4) of the central area of the cephalon (or glabella) is prominent, bulbous (or subglobular), and may overlap the border at the front in dorsal view.
[1][2] Most other Biceratopsinae, i.e. Biceratops nevadensis, Emigrantia and Peachella and to a lesser extend Eopeachella have effaced cephalic features.
In Emigrantia the genal spines are longer than the cephalon and attach halfway down its side (or lateral margin).