cingulum

The oldest taxa belong to the Middle and Late Eocene group Herodotiinae, recognisable due to molariform upper fourth premolars, a wide mesial cingulum on the upper molars and other dental characters.

The term "shingles" comes from the Latin word "cingulum," which means belt or girdle; the rash of herpes zoster often appears in a band or belt-like pattern.

Diagnostic dental characters include: 3rd upper unicuspid smaller than 4th, and unicuspids, except 5th, with a pigmented ridge extending from near apex of each tooth medially to cingulum and sometimes ending as internal cusplet.

From B. minimus, B. sawrockensis differs in: incisor less procumbent; masseteric ridge extending farther anteriorly; anterior cingulum of m2 slightly larger.

Crowns of molars strong, conical, compressed, hollowed on the inner side, with a strongly-marked lobed cingulum, especially on the inner side, and slightly developed accessory cusps before and behind.