Functional morphology and phylogenetic value of a scutal structure unique to the Ceratopogonidae (Diptera)

Examination of Culicoides species for potential synapomorphies of the genus yielded two smooth, cuticular structures (scutal areolae) on the scutum just anterior to the scutellum. Scutal areolae were documented in males and females of seven genera of Ceratopogonidae. The scutal areolae were a synapomorphy of the family, with independent losses in the Forcipomyiinae+Dasyheleinae and the Ceratopogonini. In Culicoides and Paradasyhelea, the scutal areolae were modified into raised nodules, supporting a sister group relationship of these taxa. No pores, muscles, or nerves were associated with the scutal areolae, but the structures had light-reflecting properties, indicating a possible role in intraspecific communication.