What is "microbrachius"

Microbrachius is an extinct genus of tiny, advanced antiarch placoderms closely related to the bothriolepids.

Although two of the three described species are known from Late Emsian-aged strata of Early Devonian China, the type and youngest species, M. dicki, is known from upper Givetian freshwater strata of Scotland. The various species have short thoracic armor, and large heads. There are patterns of small, but noticeable tubercles on the armor, with the arrangement varying from species to species.