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Temporal range: Emsian to Upper Givetian
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Class: Placodermi
Order: Antiarchi
Family: Microbrachiidae
Genus: Traquair, 1888
Type species
Microbrachius dicki
Traquair, 1888
  • M. dicki Traquair, 1888
  • M. sinensis Pan, 1984
  • M. chuandongensis Wang & Zhang 1999
  • Microbrachius stegmanni Hoffmann 1911

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.


M. dicki[edit]

The type species is from Upper Givetian freshwater strata of Scotland, including the John O'Groats sandstone of Caithness, and the Eday beds of the Orkney islands. Total armor length is an average of 3 centimeters..

M. sinensis[edit]

This species is from Emsian-aged freshwater strata of the Late Eifelian Qujing Formation in Middle Devonian Qujing, China, and predates M. dickii. M. sinensis differs from M. dickii in that the former has some of its tubercles arranged and fused together to form distinctive lines on its thoracic armor, and that the former is larger, with an estimated total armor length of about 3 to 4 centimeters.

M. chuandongensis[edit]

This species is endemic to the Late Emsian-aged Chuandong Formation in Qujing, China. It differs from M. sinensis primarily by having the tubercles arranged randomly.