In Depth
Like with may early discovered prehistoric animals such as the dinosaur Megalosaurus, and the pterosaur Pterodactylus, Dinichthys suffered from the waste basket taxon effect. This is where sets of remains that look similar to the holotype are assigned to the genus, but upon closer inspection they turn out to actually represent different animals. This has resulted in the long list of Dinichthys species being split up into separate genera including Eastmanosteus, Titanicthys, and the increasingly famous Dunkleosteus. Today only the original type species of Dinichthys hertzeri (sometimes spelled as herzeri) remains valid for the genus.
As an armoured placoderm fish Dinichthys would have been an apex predator at the top of the food chain. Sharks were still very small in comparison, and the giant marine reptiles would not start appearing until the Triassic period. Many of the placoderm fish had hard bony plates and the sharp powerful jaws of Dinichthys were an effective counter to this armour. Biomechanical studies have revealed the related Dunkleosteus to have a multi-ton bite force, and it’s perfectly reasonable to expect the same proportional bite force in Dinichthys.
Dinichthys had the same kind of bony armour itself, although it appears that from fossil evidence of both Dinichthys and the predatory placoderm group in general that this armour was only present upon the head and jaws. It may be that instead of being there for protection, the bony plates provided rigid fixing and support for the powerful biting muscles.
Dinichthys is often confused with Dunkleosteus because of their similar appearance, and this is not helped by the fact that reproductions of Dinichthys were for a long time based upon D. terrelli, the species that was split from Dinichthys to form the Dunkleosteus genus.
Further Reading
– Notes on Dinichthys terrelli with a restoration – The Ohio Naturalist 8 (8): 363–369 – E. B. Benson – 1908. – Two new species of Dunkleosteus Lehman, 1956, from the Ohio Shale Formation (USA, Famennian) and the Kettle Point Formation (Canada, Upper Devonian), and a cladistic analysis of the Eubrachythoraci (Placodermi, Arthrodira) – Zoological Journal of the Linnean Society 159 (1): 195–222. – R. K. Carr & V. J. Hlavin – 2010.
