Blattodea systematics in the genomic age

We review Blattodea (cockroach and termite) systematics from its inception to the present day, when it has reached the phylogenomic age. Blattodea is a diverse clade approximately 250 million years old, which is important to tropical ecosystems, has an array of parental care behaviors, and includes the oldest eusocial organisms, termites. The classification of cockroaches has evolved significantly since the 18th century, with much work still to be done. Advances in molecular and morphological studies have resolved much of the Blattodea phylogeny, yet huge gaps remain with respect to more derived relationships and extinct lineages. Additionally, it is expected that most of their diversity is undescribed in most areas globally. Given the current knowledge, we present revised definitions of the major clades, with synapomorphies for them, a character matrix, and an illustration of their placement on the currently accepted tree. In all, we summarize what is known and where the biggest gaps are in the knowledge of Blattodea taxonomy, phylogenetics, and faunistic studies (biogeography). With this synthesis, we derive 5 recommendations for advancing Blattodea systematics.