Hemicyclaspis
| Hemicyclaspis Temporal range:  
 | |
|---|---|
 
 | |
| H. murchisoni and Thyestes | |
 
 | |
| Life reconstruction. | |
| Scientific classification  | |
| Kingdom: | Animalia | 
| Phylum: | Chordata | 
| Infraphylum: | Agnatha | 
| Class: | †Osteostraci | 
| Order: | †Atelaspidiformes | 
| Family: | †Ateleaspididae | 
| Genus: | † | 
Hemicyclaspis (lit. 'half-round shield' or 'semicircle plate') is an extinct genus of primitive jawless fish, closely related to Cephalaspis, that lived in the Late Silurian (Pridoli)[1] to Devonian period in what is now Europe and North America. A typical cephalaspid, Hemicyclaspis had a heavily armored, shovel-shaped headshield. It is thought to have been a better swimmer than most of its relatives because of its powerful tail, stabilizing dorsal fin and the keel-shaped hydrodynamic edges of its head shield. Hemicyclaspis probably foraged the ocean floor for food.[2]
Hemicyclaspis grew to a length of 5 inches (13 centimeters) and would most likely have fed on particles from the muddy sea bed.


1953 plaster reconstruction.
References
- Parker, Steve. Dinosaurus: the complete guide to dinosaurs. Firefly Books Inc, 2003. Pg. 58
 
- ^ Blieck, Alain; Elliott, David K. (2017-06-01). "Pteraspidomorphs (Vertebrata), the Old Red Sandstone, and the special case of the Brecon Beacons National Park, Wales, U.K.". Proceedings of the Geologists' Association. 128 (3): 438–446. doi:10.1016/j.pgeola.2016.07.003. ISSN 0016-7878.
 - ^ Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 25. ISBN 1-84028-152-9.
 


