Blattabacterium is a genus of obligate mutualistic endosymbiont bacteria that are believed to inhabit all species of cockroach studied to date, with the exception of the genus Nocticola. The genus' presence in the termite Mastotermes darwiniensis led to speculation, later confirmed, that termites and cockroaches are evolutionarily linked. B. cuenoti was traditionally considered the only species in the genus Blattabacterium, which is in turn the only genus in the family Blattabacteriaceae; however, three new species have been described hosted by different species of cockroaches in the genus Cryptocercus: Blattabacterium relictus in Cryptocercus relictus, B. clevelandi in C. clevelandi and B. punctulatus in C. darwini, C. garciai, C. punctulatus and C. wrighti.