The Aspinothoracidi were a clade

Clade

A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 of placoderms, armored fish most diverse during the Devonian

Devonian

The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...

. The gigantic apex predator

Apex predator

Apex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...

 Dinichthys

Dinichthys

Dinichthys herzeri is an extinct, giant, marine arthrodire placoderm from the Late Devonian of Ohio and Tennessee. It was comparable in size, shape and ecological role to the better known Dunkleosteus...

, is the most well-known member of this group. Many species were previously thought to be close relatives of Dinichthys and were grouped together in the family Dinichthyidae, though more recent studies have restricted that family to only its type species.

Genera

Presently accepted genera

Genera

Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...

 are:

• Bruntonichthys
  Bruntonichthys
  Bruntonichthys is an arthrodire placoderm from the Gogo Reef Formation. It was a small fish, having proportionately huge eyes, and small jaws. Researchers suggest it may have preyed on small mollusks....
  
  
• Bullerichthys
• Dinichthys
  Dinichthys
  Dinichthys herzeri is an extinct, giant, marine arthrodire placoderm from the Late Devonian of Ohio and Tennessee. It was comparable in size, shape and ecological role to the better known Dunkleosteus...
  
  
• Gorgonichthys
  Gorgonichthys
  Gorgonichthys is an extinct arthrodire placoderm genus of the order Dinichthyoidea....
  
  
• Hadrosteus
• Heintzichthys
  Heintzichthys
  Heintzichthys gouldii is an extinct arthrodire placoderm that lived what is now Europe and North America during the Late Devonian....
  
   (including Stenognathus)
• Holdenius
  Holdenius
  Holdenius is an extinct genus of placoderm fish which lived during the Devonian period....
  
  
• Hussakofia (including Brachygnathus
  Brachygnathus
  Brachygnathus is a genus of beetles in the family Carabidae, containing the following species:* Brachygnathus angusticollis Burmeister* Brachygnathus festivus Dejean* Brachygnathus muticus Perty* Brachygnathus oxygonus Perty...
  
  )
• Kianyousteus
• Squamatognathus