Friday, August 5, 2011


Groenlandaspis (green-lind-ASP-iss) is a genus of placoderm from the late Devonian Period. It had a dorsal fin-like armor plate on top of its head, like its relative Turrisaspis. Groenlandaspis means "Greenland shield," because it was first discovered in Greenland. Fossils have since been found all over the world. 

Like other arthrodires, Groenlandaspis's neck had a joint that would allow the mouth to open wider than other kinds of fish. But its armored "dorsal fin" would keep Groenlandaspis from opening its mouth as wide as most arthordires could. So it probably would not be able to eat very large prey and would have to eat small animals and detritus.

Groenlandaspis was about three inches long and probably had to avoid large predatory placoderms. But it would probably have protection against other predators, such as Rhizodonts, because of its armored dorsal fin. 


  1. Technically, the spine is not a dorsal fin: it's a dorsal spine derived from the armor.

  2. Technically, this kid is 7. Lay off.